A practical problem that the student is likely to come across in finding the first two results is difficulty in determining the exact temperature at which solid ammonium chloride first appears since the dissolution of sodium chloride is endothermic.
This problem can be resolved by taking repeated measurements using the same mass of ammonium chloride.
What are endothermic reactions?An endothermic reaction is a reaction in which heat is absorbed from the surroundings.
In an endothermic process, there is an increase in the system's enthalpy is considered. A closed system often transfers heat into itself during such a process by absorbing thermal energy from its surroundings.
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before any reaction occurs, the concentrations of a and b in the reaction below are each 0.0420 m; the concentration of c is 0 m. what is the equilibrium constant if the concentration of a at equilibrium is 0.0124 m?
The equilibrium constant for this reaction is 0.096.
The equilibrium constant (Kc) for the following reaction is given by the ratio of the concentration of products to the concentration of reactants at equilibrium, with each concentration raised to the power of its coefficient in the balanced chemical equation:
a + b ⇌ c
Kc = [c]/([a][b])
At the beginning, the concentrations of a and b are 0.0420 M, and the concentration of c is 0 M. At equilibrium, the concentration of a is 0.0124 M. We can assume that the concentration of b at equilibrium is also 0.0124 M, since the stoichiometry of the reaction tells us that the ratio of a to b is 1:1.
Therefore, we can plug these values into the equilibrium constant expression:
Kc = [c]/([a][b]) = 0.0124^2 / (0.0420)(0.0420) = 0.096
So, the equilibrium constant for this reaction is 0.096.
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Find the ClO− concentration of a mixture that is 0.300 M in HF and 0.150 M in HClO.
Since H+ and ClO- ions are produced in a 1:1 ratio by the dissociation of HClO, the concentration of ClO- in the mixture is also 4.5 x 10⁻⁹ M.
To find the ClO- concentration in the mixture, we first need to write the balanced chemical equation for the dissociation of HClO:
HClO(aq) ⇌ H+(aq) + ClO-(aq)
The acid dissociation constant (Ka) for HClO is 3.0 x 10^-8. We can use the expression for Ka to calculate the concentration of H+ ions produced by the dissociation of HClO:
Ka = [H+][ClO-] / [HClO]
[H+] = Ka x [HClO] / [ClO-]
We can assume that the dissociation of HF is negligible compared to that of HClO, so the H+ concentration in the mixture is essentially equal to the H+ concentration produced by the dissociation of HClO.
Therefore:
[H+] = Ka x [HClO] / [ClO-]
= (3.0 x 10⁻⁹) x (0.150 M) / 1
= 4.5 x 10⁻⁹ M
Since H+ and ClO- ions are produced in a 1:1 ratio by the dissociation of HClO, the concentration of ClO- in the mixture is also 4.5 x 10⁻⁹ M.
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Air pressure at sea level is equal to: select the correct answer below: O 101,325 torr O 760 bar O 14.7 psi O all of the above
The mean air pressure at sea level is 1013.2 millibars. The correct option is A 1013.2 millibars.
The pressure within Earth's atmosphere is referred to as atmospheric pressure or barometric pressure (after the barometer). The definition of the standard atmosphere (symbol: atm) is 101,325 Pa (1,013.25 hPa), or 1013.25 millibars, 760 mm Hg, 29.9212 inches Hg, or 14.696 psi.
The Earth's mean sea-level atmospheric pressure is roughly equivalent to one atm, or one atmosphere, and is measured in the atm unit. The planet's gravitational pull on the gases above its surface produces atmospheric pressure, which depends on the planet's mass, the radius of its surface, the quantity, composition, and vertical distribution of the gases in the atmosphere. Hence, The mean air pressure at sea level is 1013.2 millibars. The correct option is A 1013.2 millibars.
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There are a few major types of reactions that occur. In a synthesis reaction, pure substances
come together. They form a chemical bond and produce new compounds. A synthesis of
2H2 and O₂ results in 2H₂O, also known as water. In a decomposition reaction, the inverse
occurs; a compound's chemical bonds break. Both synthesis and decomposition result in
new substances but not new atoms, and no matter is created or destroyed.
Based on the passage, synthesis can best be described as
A
B
с
D
the opposite of decomposition.
the same as decomposition.
the result of decomposition.
the cause of decomposition.
According to the passage, synthesis can best be described as the opposite of decomposition. Option A is correct.
Synthesis and decomposition are two major types of chemical reactions. Synthesis reactions involve the combination of two or more pure substances to form a new compound. This process involves the formation of chemical bonds, resulting in the creation of a new substance. In contrast, decomposition reactions involve the breaking of chemical bonds in a compound, leading to the formation of two or more simpler substances.
The passage states that synthesis and decomposition reactions both result in new substances but not new atoms, and no matter is created or destroyed. However, synthesis and decomposition reactions are opposite processes; synthesis involves combining substances, while decomposition involves breaking them apart. Therefore, the best description of synthesis based on the passage is the opposite of decomposition. Option A is correct.
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which of the following solutions of glucose (c6h12o6) is isotonic with a 0.1 m nacl solution?
3.6 %(w/v) solutions of glucose (C₆H₁₂O₆) is isotonic with a 0.1 m nacl solution from the following .
Option C is correct.
NaCl Na⁺ + Cl⁻ = 2 particles
mol of 0.1 M NaCl = 0.1 x 2 = 0.2 Osmol NaCl
Glucose does not dissociate to particles so 0.2
Mol glucose = 0.2 M glucose
0.2 M glucose = 0.2 mol glucose/1 L solution
= 0.02 mol/100 mL
1 mol glucose (C₆H₁₂O₆) = 6 x 12 g + 12 x 1 g + 6 x 16 g
= 180 g glucose
0.02 mol glucose x 180 g glucose = 3.6 g glucose 3.6 g glucose/100 mL solution
1 mol glucose = 3.6 %(w/v) glucose solution.
Isotonic solution: what is it?Isotonic solutions are those that have the same concentration of water and solutes as the cytoplasm of the cell. Since there is no net gain or loss of water in an isotonic solution, cells placed there will not swell or shrink. Isotonic is a term used to portray arrangements and science and, once in a while, muscles in human science.
When a solution crosses a semipermeable membrane with the same concentration of solutes as another solution, it is said to be isotonic in chemistry. The utilization of isotonic in human life structures is utilized all the more once in a blue moon
Incomplete question :
Which of the following solutions of glucose (C6H12O6) is isotonic with a 0.1 M NaCl solution?
A. 0.15%(w/v)
B. 0.55%(w/v)
C. 3.6 %(w/v)
D. 5.4%(w/v)
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Calculate the pH during the titration of 20.00 mLof 0.1000 M CH3CH2CH2COOH(aq) with0.1000 M NaOH(aq) after 19.87 mL of the base have beenadded.
Ka of butanoic acid = 1.54 x 10-5.
The pH of butanoic acid after titration with NaOH is 5.00 when 19.87 mL of base is added.
How to calculate pH?First, write out the balanced chemical equation for the reaction:
CH₃CH₂CH₂COOH(aq) + NaOH(aq) → CH₃CH₂CH₂COONa(aq) + H₂O(l)
Since the initial volume of butanoic acid is 20.00 mL and the concentration is 0.1000 M, the initial moles of butanoic acid are:
n = V x C = (20.00 mL) x (0.1000 mol/L) = 0.00200 mol
Next, determine how many moles of NaOH were added to reach the endpoint. The volume of NaOH added at the endpoint is 19.87 mL, but convert this to liters to use it in the calculation:
V(NaOH) = 19.87 mL ÷ 1000 mL/L = 0.01987 L
The number of moles of NaOH added is:
n(NaOH) = V(NaOH) x C(NaOH) = (0.01987 L) x (0.1000 mol/L) = 0.001987 mol
Since the stoichiometric ratio of butanoic acid to NaOH is 1:1, this means that 0.001987 mol of butanoic acid were neutralized by the NaOH.
The moles of butanoic acid remaining after the titration is:
n(BA) = n(initial) - n(NaOH) = 0.00200 mol - 0.001987 mol = 0.000013 mol
The concentration of butanoic acid remaining in solution is:
C(BA) = n(BA) / V = 0.000013 mol / 0.02000 L = 6.5 x 10⁻⁴ M
To determine the pH at this point, use the equilibrium expression for butanoic acid:
Ka = [CH₃CH₂CH₂COO⁻][H₃O⁺] / [CH₃CH₂CH₂COOH]
Assume that the concentration of H₃O⁺ is equal to the concentration of OH⁻ added by the NaOH, which is:
[OH-] = n(NaOH) / V = 0.001987 mol / 0.02000 L = 0.09935 M
Since we know the value of Ka and the concentrations of the butanoic acid and its conjugate base, we can rearrange the equilibrium expression to solve for [H₃O⁺]:
[H3O+] = (Ka x [CH₃CH₂CH₂COOH]) / [CH₃CH₂CH₂COO⁻]
= (1.54 x 10⁻⁵) x (6.5 x 10⁻⁴ M) / (0.1000 M - 6.5 x 10⁻⁴ M)
= 1.00 x 10⁻⁵ M
Finally, use the definition of pH to calculate the pH:
pH = -log[H₃O⁺] = -log(1.00 x 10⁻⁵) = 5.00
Therefore, the pH during the titration of butanoic acid with NaOH after 19.87 mL of the base have been added is 5.00.
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explain, in terms of zn atoms and zn ions, why the mass of the zn electrode decreases as the cell operates.
The mass of the Zn electrode decreases as the cell operates because the Zn ions are falling into the solution.
The galvanic cell consists of two pieces of metal, one is zinc and the other is copper. These pieces are immersed in a solution containing a dissolved salt of the corresponding metal. The mixing of these two solutions is prevented by separating them with a porous barrier. But the ions are allowed to diffuse through the barrier.
When the cell operates, the Zn electrode loses its mass. Therefore, when we connect zinc and copper by a metallic conductor, the zinc electrode gets oxidized in the cell and increases the concentration of [tex]Zn^{+2}[/tex] ions in the solution. These ions flow through the external circuit from the left cell into the right electrode where they could be delivered to the [tex]Cu^{+2}[/tex] ions.
[tex]Zn(s) - > Zn^{2+ } + 2e^{-}[/tex]
Therefore, the mass of the zinc electrode decreases as the cell operates because it is now an anode after being oxidized to [tex]Zn^{2+}[/tex] ions that are falling into the solution.
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an unknown radioactive substance has a half-life of 3.20 hours . if 34.4 g of the substance is currently present, what mass a0 was present 8.00 hours ago? express your answer with the appropriate units
The initial mass of the substance 8.00 hours ago was 195 g. A radioactive substance is one that spontaneously emits radiation, such as alpha or beta particles, in order to become more stable. The half-life of a radioactive substance is the amount of time it takes for half of the original sample to decay or emit radiation.
Now, let's move on to solving the problem. We know that the half-life of the substance is 3.20 hours, which means that after 3.20 hours, half of the original sample will have decayed or emitted radiation. We also know that currently, 34.4 g of the substance is present.
Using this information, we can set up the following equation:
34.4 g = a0 (1/2)^(8.00/3.20)
Here, a0 represents the initial mass of the substance, before any decay occurred. We are trying to solve for a0.
Let's break down the equation. The term (1/2)^(8.00/3.20) represents the fraction of the original sample that remains after 8.00 hours, based on the half-life. We can simplify this fraction to (1/2)^2.5, which is approximately 0.176.
Plugging in the numbers and solving for a0, we get:
a0 = 34.4 g / 0.176
a0 = 195 g (rounded to three significant figures)
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Use the data in the table to calculate the equilibrium constant for the following reaction.
HCOOH(aq)+ OH −(aq) equilibrium reaction arrow HCOO−(aq)+ H2O(l)
HCOO is 5.9e-11 (Kb)
HCOOH is 1.7e-4 (Ka)
Not sure how to find the equilibrium constant given this information
The equilibrium constant for the reaction HCOOH(aq) + OH-(aq) <-> HCOO-(aq) + H2O(l) is 2.89 x 10^6 at 25°C.
You can use the relationship between the equilibrium constants of the acid dissociation (Ka) and its conjugate base (Kb) to calculate the equilibrium constant (K) for the reaction between HCOOH and OH-:
K = (Kw) / Ka
where Kw is the ion product constant for water (1.0 x 10^-14 at 25°C).
First, calculate Kb for the conjugate base HCOO- using the relationship:
Kw = Ka x Kb
Kb = Kw / Ka
Kb = (1.0 x 10^-14) / (5.9 x 10^-11)
Kb = 1.7 x 10^-4
Then, use the relationship between Ka, Kb, and K to solve for K:
K = (Kw) / Ka = (Kb x Ka) / Kw
K = [(1.7 x 10^-4) x (1.7 x 10^-4)] / (1.0 x 10^-14)
K = 2.89 x 10^6
Therefore, the equilibrium constant for the reaction HCOOH(aq) + OH-(aq) <-> HCOO-(aq) + H2O(l) is 2.89 x 10^6 at 25°C.
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the specific heat capacity of lead is 0.13j/g*k. how much heat energy (j) is required the temperature of 15g of lead from 22oc to 37oc?
It would require 29.25 joules of heat energy to raise the temperature of 15 grams of lead from 22°C to 37°C.
The specific heat capacity of a substance is the amount of heat energy required to raise the temperature of one gram of the substance by one degree Celsius (or Kelvin). In this case, the specific heat capacity of lead is given as 0.13 J/g*K, which means that 0.13 joules of heat energy are required to raise the temperature of one gram of lead by one degree Celsius.
To calculate the heat energy required to raise the temperature of 15 grams of lead from 22°C to 37°C, we can use the following formula:
Q = m * c * ΔT
where Q is the heat energy required, m is the mass of the substance, c is the specific heat capacity of the substance, and ΔT is the change in temperature.
Substituting the given values, we get:
Q = 15 g * 0.13 J/g*K * (37°C - 22°C)
Q = 15 g * 0.13 J/g*K * 15°C
Q = 29.25 J
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The type your answer... is an application of Le Chatelier principle to solubility equilibria. If silver nitrate solution is added to a solution which is 0.050 M in both Cland Brlons, at what (Ae" would precipitation begin, and what would be the formula of the precipitate? AgCl(s) Ag" (ac)+(aa) Ksp-1.6x10-10 AgBr(s) Ag" (aq) + Br"aa) Ksp 5,0x10-13 Input all results with 2 signes Silver choose your answer. will precipitate first, when the concentration of the silver ions reaches type your answer 10" type your answer
Precipitation of AgCl will begin when the concentration of Ag+ ions in the solution reaches approximately 3.2 x 10^-9 M. The precipitate will be silver chloride (AgCl).
The precipitation of silver chloride (AgCl) or silver bromide (AgBr) will occur when the product of the concentrations of Ag+ and Cl- or Br-, respectively, exceeds their respective solubility product constants.
For AgCl, the solubility product constant (Ksp) is 1.6 x 10^-10. Therefore,
Ksp = [Ag+][Cl-] = (x)(0.050)
where x is the molar solubility of AgCl in the solution.
Solving for x, we get:
x = sqrt(Ksp/[Cl-]) = sqrt(1.6 x 10^-10 / 0.050) ≈ 1.0 x 10^-6 M
So the molar solubility of AgCl in the solution is approximately 1.0 x 10^-6 M.
For AgBr, the solubility product constant (Ksp) is 5.0 x 10^-13. Therefore,
Ksp = [Ag+][Br-] = (x)(0.050)
where x is the molar solubility of AgBr in the solution.
Solving for x, we get:
x = sqrt(Ksp/[Br-]) = sqrt(5.0 x 10^-13 / 0.050) ≈ 3.2 x 10^-7 M
So the molar solubility of AgBr in the solution is approximately 3.2 x 10^-7 M.
Since AgCl has a lower molar solubility than AgBr in this solution, it will precipitate first. The precipitation of AgCl will begin when the concentration of Ag+ ions in the solution reaches the solubility product constant for AgCl:
Ksp = [Ag+][Cl-]
1.6 x 10^-10 = (x)(0.050)
x = 3.2 x 10^-9 M
Therefore, precipitation of AgCl will begin when the concentration of Ag+ ions in the solution reaches approximately 3.2 x 10^-9 M.
The formula of the precipitate will be AgCl, as determined by the precipitation reaction:
Ag+(aq) + Cl-(aq) → AgCl(s)
So the precipitate will be silver chloride (AgCl).
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Cu3(PO4)2(s) + HCl(aq) → CuCl2(aq) + H3PO4(aq)
CuCl(aq) + Mg(s) →M gCl2(aq) + Cu(s) Cu(s) + 4HNO3(aq) → Cu(NO3)2(aq) + 2NO2(g) Place them in the proper order such that the first reaction starts with elemental copper and the fourth reaction ends with the production of elemental copper, and balance where needed.
The proper order for the given reactions, starting with elemental copper and ending with the production of elemental copper, is as follows:
Cu(s) + 4HNO₃(aq) → Cu(NO₃)₂(aq) + 2NO₂(g)
Cu(NO₃)₂(aq) + 2HCl(aq) → CuCl₂(aq) + 2HNO₃(aq)
CuCl₂(aq) + Mg(s) → MgCl₂(aq) + Cu(s)
1. The first reaction involves elemental copper (Cu) reacting with nitric acid (HNO₃) to form copper(II) nitrate (Cu(NO₃)₂) and nitrogen dioxide (NO₂) gas.
2. In the second reaction, copper(II) nitrate (Cu(NO₃)₂) reacts with hydrochloric acid (HCl) to produce copper(II) chloride (CuCl₂) and nitric acid (HNO₃).
3. The third reaction involves copper(II) chloride (CuCl₂) reacting with magnesium (Mg) to form magnesium chloride (MgCl₂) and elemental copper (Cu).
By arranging the reactions in this order, we ensure that the first reaction starts with elemental copper and the fourth reaction ends with the production of elemental copper. It is important to balance the reactions to ensure the conservation of mass, as indicated in the balanced equations provided in the original question.
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in the spectra, the reason why aspirin contains 4 peaks in the aromatic region is
The four peaks observed in the aromatic region of the infrared spectrum of aspirin are due to the presence of an aromatic ring in the molecule's chemical structure.
Aspirin, also known as acetylsalicylic acid, contains a six-carbon benzene ring that has a characteristic absorption pattern in the aromatic region of the infrared spectrum.
The number of peaks in the aromatic region of the infrared spectrum depends on the number and symmetry of the hydrogen atoms attached to the aromatic ring. The four peaks observed in the aromatic region of the spectrum of aspirin correspond to the different vibrations of the hydrogen atoms attached to the benzene ring.
These peaks' positions and intensities can provide information about the specific functional groups present in the molecule, as well as the sample's purity and quality. Therefore, the four peaks observed in the aromatic region of the spectrum of aspirin can be used to identify and confirm the presence of the benzene ring in the molecule.
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if a substance has a half-life of 4.4 hr, how many hours will it take for 28 g of the substance to be depleted to 3.5 g?
It will take 13.2 hours for 28 g of the substance to be depleted to 3.5 g.
How to calculate hours that will take for 28 g of the substance to be depleted to 3.5 g?We can use the following radioactive decay formula to solve this problem:
N = N0 * (1/2)^(t/T)
Where:
N = Final amount of the substance
N0 = Initial amount of the substance
t = Time passed
T = Half-life of the substance
Let's first find the number of half-lives that will pass as 28 g of the substance is depleted to 3.5 g:
28 g * (1/2)^(n) = 3.5 g
(1/2)^(n) = 3.5 g / 28 g
(1/2)^(n) = 0.125
n = log(0.125)/log(1/2)
n = 3
So, 3 half-lives will pass. Since the half-life is 4.4 hours, the total time it will take is:
t = n * T
t = 3 * 4.4 hr
t = 13.2 hr
Therefore, it will take 13.2 hours for 28 g of the substance to be depleted to 3.5 g.
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Help me do #2 Due tdy!
The area of chemistry known as stoichiometry is focused on the proportions of reactants and products in chemical processes.
Thus, Whole numbers (coefficients) are used to represent the quantities (often in moles) of both the reactants and products in any balanced chemical reaction.
One mole of oxygen combines with two moles of hydrogen, for instance, to create two moles of water when oxygen and hydrogen combine to form that substance.
Additionally, stoichiometry can be used to determine values like the percentage yield and the number of products that can be made from a given quantity of reactants. The calculation of the number of items that can be produced given specific information will be covered in upcoming topics.
Thus, The area of chemistry known as stoichiometry is focused on the proportions of reactants and products in chemical processes.
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consider the reaction and its rate law. 4a 3b⟶products
rate=[a]2[b]2
What is the order with respect to A?
What is the order with respect to B?
What is the overall reaction order?
The order with respect to A is 2, the order with respect to B is 2, and the overall reaction order is 4.
The given reaction is 4A + 3B ⟶ products, and the rate law is rate = [A]^2[B]^2.
1. The order with respect to A is 2. This is because the rate law shows that the rate depends on the concentration of A raised to the power of 2, i.e., [A]^2.
2. The order with respect to B is also 2. This is due to the rate law indicating that the rate depends on the concentration of B raised to the power of 2, i.e., [B]^2.
3. The overall reaction order is the sum of the orders with respect to each reactant. In this case, the overall order is 2 (from A) + 2 (from B) = 4.
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a solution is made by mixing of thiophene and of benzene . calculate the mole fraction of thiophene in this solution. round your answer to significant digits.
To calculate the mole fraction of thiophene in the solution, we need to first determine the total number of moles present in the solution. This can be done by dividing the mass of each component by its respective molar mass, and adding the two values together. Assuming equal mass of both components, we can simplify the calculation as follows:
Moles of thiophene + Moles of benzene = Total moles in solution
Let's assume we have 100 grams of the mixture (50 grams of each component), and the molar mass of thiophene is 84 g/mol and the molar mass of benzene is 78 g/mol. Therefore:
(50 g / 84 g/mol) + (50 g / 78 g/mol) = 0.595 moles
Next, we can calculate the mole fraction of thiophene by dividing the moles of thiophene by the total moles in the solution:
Mole fraction of thiophene = (0.50 moles / 0.595 moles) = 0.84
Rounding to significant digits, the mole fraction of thiophene in the solution is 0.84.
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how does the monomer of polyvinyl chloride (pvc) differ from the monomer of polyethylene (pe)?
The monomer of polyvinyl chloride (PVC) differs from the monomer of polyethylene (PE) in their chemical structures and properties. since the monomer of PVC is vinyl chloride and the monomer of PE is ethylene.
What are the monomers of PVC and PE?The monomer of polyvinyl chloride (PVC) differs from the monomer of polyethylene (PE) in its chemical structure. PVC is derived from the monomer vinyl chloride, which has a structure consisting of a vinyl group (CH2=CH-) attached to a chloride atom. PE, on the other hand, is derived from the monomer ethylene, which has a structure consisting of two carbon atoms with a double bond between them (CH2=CH2).
The main difference is the presence of a chlorine atom (Cl) in the vinyl chloride monomer, while the ethylene monomer only consists of carbon and hydrogen atoms. This difference in structure leads to variations in the properties and applications of the resulting polymers, PVC and PE. PVC is often used in construction materials, pipes, and electrical cables, while PE is commonly used in packaging materials, plastic bags, and containers.
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Compare the ir spectra for 9-anthraldehyde and that of your product. What evidence allows you to conclude that your product is trans-9-(2-Phenylethenyl)-anthracene? I don't have the spectrum for the 9-anthraldehyde, but here's the spectrum for my product. And part BRUKER D CO UNO CCO 3000 2000 2500 1500 1000 3500 500 Wavenumber cm-1 27/09/2017 COPUS_. 7. 2. 1391294 MEASATRO602141696 Organic Chemistry
In the case of trans-9-(2-Phenylethenyl)-anthracene, one might expect to see peaks in the IR spectrum corresponding to the aromatic ring and the C=C double bond.
A double bond is a type of chemical bond in which two atoms share two pairs of electrons. It is formed when two atoms, typically carbon or oxygen, are bonded to each other and share four electrons in a covalent bond. The double bond is represented in chemical formulas as a double line between the atoms.
In a double bond, the shared electrons are held more tightly between the atoms than in a single bond, making the double bond stronger and shorter than a single bond. This increased bond strength and shorter bond length can have important implications for the chemical and physical properties of the compound. Molecules with double bonds are often more reactive than those with single bonds, as the shared electrons in the double bond are more available for chemical reactions.
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a 20.0 ml sample of a 0.125 m monoprotic acid solution is titrated with naoh(aq) solution of solution of unknown concentration. based on the titration curve to the right, what is the molar concentration of naoh(aq)? 0.063 m 0.125 m 0.250 m 0.500 m
Based on the titration curve provided, the equivalence point is reached at around 25 mL of NaOH solution, which means that 25 mL of NaOH solution is required to completely react with the 20.0 mL of 0.125 M monoprotic acid solution.
At the equivalence point, moles of acid = moles of base.
Moles of acid in the sample = (20.0 mL) x (0.125 mol/L) = 2.50 x 10^-3 moles
Therefore, the number of moles of NaOH needed to reach the equivalence point is also 2.50 x 10^-3 moles.
From the titration curve, we can see that the concentration of NaOH is 0.100 M.
Moles of NaOH = (25.0 mL) x (0.100 mol/L) = 2.50 x 10^-3 moles
Since the number of moles of NaOH needed to reach the equivalence point is the same as the number of moles of acid in the sample, the molar concentration of NaOH can be calculated as follows:
Molarity of NaOH = moles of NaOH / volume of NaOH solution used
Molarity of NaOH = (2.50 x 10^-3 moles) / (25.0 mL) = 0.100 M
Therefore, the molar concentration of NaOH(aq) is 0.100 M.
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a chemistry graduate student is given 250 ml of a 0.20 m ammonia solution. ammonia is a weak base with . what mass of nh4cl should the student dissolve in the solution to turn it into a buffer with ph ? you may assume that the volume of the solution doesn't change when the is dissolved in it. be sure your answer has a unit symbol, and round it to significant digits.
The student should dissolve 1.87 g of NH4Cl in the given 250 mL 0.20 M NH3 solution to create a buffer with pH 9.0.
Figure out buffer with ph?To turn the given ammonia solution into a buffer with a specific pH, we need to add its conjugate acid, ammonium ion (NH4+), and its amount should be such that the pH of the buffer is equal to the desired pH.
First, we need to calculate the concentration of NH3 in the given solution.
Given,
Volume of solution = 250 mL = 0.25 L
Molarity of NH3 solution = 0.20 M
The number of moles of NH3 in 0.25 L of 0.20 M solution = 0.20 x 0.25 = 0.05 moles
NH3 + H2O ⇌ NH4+ + OH-
The dissociation constant of NH3, Kb = 1.8 x 10^-5
Using the Kb expression, we can calculate the concentration of OH- ions in the solution.
Kb = [NH4+][OH-]/[NH3]
Since the concentration of OH- ions is very small compared to NH3 and NH4+, we can assume that [OH-] = [NH4+]
So, Kb = [NH4+]^2/[NH3]
[NH4+] = √(Kb x [NH3]) = √(1.8 x 10^-5 x 0.05) = 1.5 x 10^-3 M
Now, we need to calculate the amount of NH4Cl to be added to the solution to get the desired pH.
Let's assume we want to create a buffer with pH 9.0.
The Henderson-Hasselbalch equation for a buffer is pH = pKa + log([A-]/[HA])
We know that the pKa of NH4+/NH3 buffer is 9.25 (from tables or calculation).
pH = 9.0, pKa = 9.25, [A-] = [NH3] = 0.05 M, and [HA] = [NH4+]
9.0 = 9.25 + log([NH4+]/0.05)
log([NH4+]/0.05) = -0.25
[NH4+] = 0.05 x 10^(-0.25) = 0.035 M
The amount of NH4Cl needed to prepare 0.035 M NH4+ solution can be calculated by stoichiometry.
NH4Cl → NH4+ + Cl-
1 mole of NH4Cl produces 1 mole of NH4+
So, 0.035 moles of NH4+ requires 0.035 moles of NH4Cl
The molar mass of NH4Cl is 53.5 g/mol.
The mass of NH4Cl required = 0.035 x 53.5 = 1.87 g
The student should dissolve 1.87 g of NH4Cl in the given 250 mL 0.20 M NH3 solution to create a buffer with pH 9.0.
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which of the following statements is true about bond energies in this reaction? responses the energy absorbed as the bonds in the reactants are broken is greater than the energy released as the bonds in the product are formed. the energy absorbed as the bonds in the reactants are broken is greater than the energy released as the bonds in the product are formed. the energy released as the bonds in the reactants are broken is greater than the energy absorbed as the bonds in the product are formed. the energy released as the bonds in the reactants are broken is greater than the energy absorbed as the bonds in the product are formed. the energy absorbed as the bonds in the reactants are broken is less than the energy released as the bonds in the product are formed. the energy absorbed as the bonds in the reactants are broken is less than the energy released as the bonds in the product are formed. the energy released as the bonds in the reactants are broken is less than the energy absorbed as the bonds in the product are formed.
In a chemical reaction, bonds in the reactants are broken and new bonds are formed in the products. The energy required to break a bond is known as bond energy. The energy released when new bonds are formed is also bond energy.
In order to determine the true statement about bond energies in a reaction, we need to compare the energy required to break the bonds in the reactants to the energy released when new bonds are formed in the products. If the energy absorbed as the bonds in the reactants are broken is greater than the energy released as the bonds in the product are formed, then the reaction is endothermic, meaning it requires energy input to occur. Conversely, if the energy released as the bonds in the reactants are broken is greater than the energy absorbed as the bonds in the product are formed, then the reaction is exothermic, meaning it releases energy.
Based on this, we can conclude that the true statement about bond energies in a reaction is that the energy released as the bonds in the reactants are broken is greater than the energy absorbed as the bonds in the product are formed. This means that the reaction is exothermic and releases energy.
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The reaction CH3I + HI → CH4 + I2 was observed to have rate constants k = 3.2 L mol-1 s-1 at 355 °C and k = 23 L mol-1 s-1 at 405 °C.What is the value of Ea expressed in kJ/mol? Ea = ______× 102 kJ/mol.What would be the rate constant at 398 °C? ________ L mol–1 s–1.
The rate constant at 398 °C would be approximately 10.5 L mol–1 s–1.To calculate the activation energy (Ea), we can use the Arrhenius equation: k = A * exp(-Ea/RT)
where k is the rate constant, A is the pre-exponential factor, Ea is the activation energy, R is the gas constant (8.314 J/K mol), and T is the temperature in Kelvin.
We can use the two given rate constants and their corresponding temperatures to create two equations with two unknowns (A and Ea) and then solve for Ea.
ln(k1/k2) = Ea/R * (1/T2 - 1/T1)
where k1 and T1 are the rate constant and temperature at 355 °C and k2 and T2 are the rate constant and temperature at 405 °C. Plugging in the values, we get: ln(3.2/23) = Ea/(8.314*[tex]10^{3}[/tex]) * (1/678 - 1/728)
Solving for Ea, we get: Ea = 80.8 kJ/mol
To calculate the rate constant at 398 °C, we can use the same Arrhenius equation with the Ea we just calculated and the given temperature: k = A * exp(-Ea/RT), k = A * exp([tex]-80.810^{3}[/tex]/([tex]8.31410^{3}[/tex] * 671)), k = 10.5 L mol–1 s–1 (approximately)
So the rate constant at 398 °C would be approximately 10.5 L mol–1 s–1.
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formamide, hc(o)nh2, is prepared at high pressures from carbon monoxide and ammonia and serves as an industrial solvent. h-c-n-h (showing how atoms are bonded) ....|. | ...o h two resonance forms can be written for formamide which satisfy the octet rule (one with no formal charges and one with formal charges). write both resonance structures. for the resonance structure with no formal charges, what is the o-c-n bond angle ?
The answer is that two resonance forms can be written for formamide, one with no formal charges and one with formal charges. The resonance forms satisfy the octet rule.
For the resonance structure with no formal charges, the O-C-N bond angle is approximately 120 degrees.
Formamide, HC(O)NH2, is a compound that is prepared at high pressures from carbon monoxide and ammonia. It is commonly used as an industrial solvent due to its ability to dissolve a wide variety of substances. The structure of formamide can be represented as H-C-N-H, showing how the atoms are bonded.
Resonance structures are multiple forms of a molecule that differ only in the position of electrons. For formamide, two resonance forms can be written that satisfy the octet rule. One resonance form has no formal charges, while the other has formal charges. The resonance structure with no formal charges has a double bond between the oxygen and carbon atoms and a single bond between the carbon and nitrogen atoms.
The bond angles in this structure are similar to those found in a typical trigonal planar molecule, so the O-C-N bond angle is approximately 120 degrees.
In summary, formamide is a compound that is prepared from carbon monoxide and ammonia and is commonly used as an industrial solvent. Two resonance forms can be written for formamide, one with no formal charges and one with formal charges. For the resonance structure with no formal charges, the O-C-N bond angle is approximately 120 degrees.
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How do air masses move in the
atmosphere?
Choose 1 answer:
A from areas of high pressure to areas of low pressure
B from areas of low pressure to
areas of high pressure
C between areas of equal
pressure
From high-pressure zones to low-pressure zones, air masses travel. This is caused by the pressure gradient force, which propels air masses to travel from high pressure to low pressure regions.
The variations in air pressure between two places are what provide this pressure gradient force. The air is pushed by the higher pressure and dragged by the lower pressure as it goes from a location of high pressure to a zone of low pressure.
Due to the air shifting from a high to a low pressure area, winds and other weather patterns are produced.
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Note the first distillation is an example of steam distillation. what is meant by the term steam distillation?
Steam distillation is a method of separating volatile compounds from non-volatile substances using steam. This technique is used when the substances being distilled have high boiling points and are not easily vaporized at low temperatures. By using steam, the boiling points of the substances being distilled are lowered, allowing them to vaporize and be collected separately.
The process of steam distillation involves passing steam through a mixture of the substances being distilled. The steam carries the volatile compounds with it, and the mixture is then condensed to separate the volatile compounds from the non-volatile substances. The volatile compounds can then be collected as a separate product.
One of the advantages of steam distillation is that it is a gentle method that preserves the natural properties of the substances being distilled. It is commonly used in the extraction of essential oils from plants, as well as in the production of alcoholic beverages and other compounds.
Overall, steam distillation is a useful technique that allows for the separation of volatile compounds from non-volatile substances. It is a gentle and effective method that is widely used in many industries.
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calculate the ph of a solution that is 0.488 m morphine c17h19o3n and 0.145 m morphine hydrochloride c17h20o3ncl. kb of c17h19o3n is 1.6 x 10-6.
The pH of the given solution is 10.34. Morphine (C17H19O3N) and morphine hydrochloride (C17H20O3NCl) can be considered as a weak base and its conjugate acid, respectively. The dissociation of morphine in water is as follows: C17H19O3N + H2O ⇌ C17H19O3NH+ + OH-
The equilibrium constant expression for the above reaction is: Kb = [C17H19O3NH+][OH-]/[C17H19O3N]. Morphine hydrochloride will dissociate in water to form morphine and H+ ions: C17H20O3NCl → C17H19O3N + H+ + Cl-.
To calculate the pH of the given solution, we can consider the dissociation of morphine only and calculate the concentration of hydroxide ions. Then, we can use the relationship:
pH + pOH = 14
First, we need to calculate the concentration of hydroxide ions:
Kb = [C17H19O3NH+][OH-]/[C17H19O3N]
1.6 x 10^-6 = x^2 / (0.488 - x)
Since the concentration of OH- is very small compared to the initial concentration of morphine, we can assume that x is negligible compared to 0.488. Therefore:
1.6 x 10^-6 = x^2 / 0.488
x = √(1.6 x 10^-6 x 0.488) = 2.20 x 10^-4 M
Now, we can use the relationship pH + pOH = 14 to calculate the pH of the solution:
pOH = -log[OH-] = -log(2.20 x 10^-4) = 3.66
pH = 14 - pOH = 14 - 3.66 = 10.34
Therefore, the pH of the given solution is 10.34.
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explain how a solution of two volatile components with strong solute-solvent attractions deviates from raoult's law. explain how a solution of two volatile components with strong solute-solvent attractions deviates from raoult's law. strong solute-solvent interactions lower the number of particles that have enough energy to escape the solution as compared to pure component, therefore lowering the vapor pressure. strong solute-solvent interactions increase the number of particles that have enough energy to escape the solution as compared to either pure component, therefore increasing the vapor pressure. strong solute-solvent interactions lower the number of particles that have enough energy to remain in the solution as compared to either pure component, therefore increasing the vapor pressure. strong solute-solvent interactions increase the number of particles that have enough energy to remain in the solution as compared to either pure component, therefore lowering the vapor pressure.
When a solution is composed of two volatile components with strong solute-solvent attractions, it deviates from Raoult's law.
Raoult's law states that the vapor pressure of a component in a solution is directly proportional to its mole fraction in the solution.
In a solution with strong solute-solvent attractions, the solute molecules interact strongly with the solvent molecules, affecting the behavior of both components.
Raoult's law assumes that the vapor pressure of each component in the solution is determined solely by its mole fraction and the vapor pressure of the pure component. However, in the case of strong solute-solvent attractions, the solute-solvent interactions alter the behavior of the components, leading to deviations from Raoult's law.
A possible deviation is that the solute-solvent interactions lower the number of solvent molecules that have enough energy to escape the solution and form a vapor phase. This reduces the effective vapor pressure of the solvent in the solution. The solute molecules restrict the movement of the solvent molecules, making it more difficult for them to escape and evaporate. As a result, the observed vapor pressure of the solvent is lower than predicted by Raoult's law.
Hence, solution of two volatile components with strong solute-solvent attractions deviates from Raoult's law.
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Complete Question: Explain how a solution of two volatile components with strong solute-solvent attractions deviates from raoult's law.
Write the chemical equation for the ionization of each of the following weak acids in water. (Some are polyprotic acids; for these write only the equation for the first step in the ionization.) Do not include physical states, and use the smallest possible integer coefficientsa) HNO2b) HAsO42−c)(CH3)3NH
Answer:
a)HNO2 + H2O → H3O+ + NO2−
b)HAsO42− + H2O ⇌ H3O+ + H2AsO4−
c)(CH3)3NH + H2O ⇌ (CH3)3NH+ + OH−
Explanation:
a) The ionization of HNO2 in water is:
HNO2 + H2O → H3O+ + NO2−
b) The ionization of HAsO42− in water is:
HAsO42− + H2O ⇌ H3O+ + H2AsO4−
c) The ionization of (CH3)3NH in water is:
(CH3)3NH + H2O ⇌ (CH3)3NH+ + OH−
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how many moles of sulfate are in 23 moles of MgSO4?