Answer:
Explanation:
Mass of Erlenmeyer flask + KHP = 84.847 g
Mass of Erlenmeyer flask = 84.347 g
Mass of KHP = .5 g
moles of KHP = .5 / 204.23
= 2.448 x 10⁻³ moles
moles of NaOH reacted = 2.448 x 10⁻³
Final buret reading = 12.25 mL
Initial buret reading = 0.50 mL
Volume of NaOH added=
Calculate the standard enthalpy change for the reaction at 25 ∘ C. Standard enthalpy of formation values can be found in this list of thermodynamic properties.HCl(g)+NaOH(s)⟶NaCl(s)+H2O(l)
Answer:
-179.06 kJ
Explanation:
Let's consider the following balanced reaction.
HCl(g) + NaOH(s) ⟶ NaCl(s) + H₂O(l)
We can calculate the standard enthalpy change for the reaction (ΔH°r) using the following expression.
ΔH°r = 1 mol × ΔH°f(NaCl(s)) + 1 mol × ΔH°f(H₂O(l)) - 1 mol × ΔH°f(HCl(g)) - 1 mol × ΔH°f(NaOH(s))
ΔH°r = 1 mol × (-411.15 kJ/mol) + 1 mol × (-285.83 kJ/mol) - 1 mol × (-92.31 kJ/mol) - 1 mol × (-425.61 kJ/mol)
ΔH°r = -179.06 kJ
A certain radioactive nuclide has a half life of 1.00 hour(s). Calculate the rate constant for this nuclide. s-1 Calculate the decay rate for 1.000 mole of this nuclide. decays s-1
Answer:
k= 1.925×10^-4 s^-1
1.2 ×10^20 atoms/s
Explanation:
From the information provided;
t1/2=Half life= 1.00 hour or 3600 seconds
Then;
t1/2= 0.693/k
Where k= rate constant
k= 0.693/t1/2 = 0.693/3600
k= 1.925×10^-4 s^-1
Since 1 mole of the nuclide contains 6.02×10^23 atoms
Rate of decay= rate constant × number of atoms
Rate of decay = 1.925×10^-4 s^-1 ×6.02×10^23 atoms
Rate of decay= 1.2 ×10^20 atoms/s
A chemistry student weighs out of lactic acid into a volumetric flask and dilutes to the mark with distilled water. He plans to titrate the acid with solution. Calculate the volume of solution the student will need to add to reach the equivalence point. Round your answer to significant digits
Answer:
28.0mL of the 0.0500M NaOH solution
Explanation:
0.126g of lactic acid diluted to 250mL. Titrated with 0.0500M NaOH solution.
The reaction of lactic acid, H₃C-CH(OH)-COOH (Molar mass: 90.08g/mol) with NaOH is:
H₃C-CH(OH)-COOH + NaOH → H₃C-CH(OH)-COO⁻ + Na⁺ + H₂O
Where 1 mole of the acid reacts per mole of the base.
You must know the student will reach equivalence point when moles of lactic acid = moles NaOH.
the student will titrate the 0.126g of H₃C-CH(OH)-COOH. In moles (Using molar mass) are:
0.126g ₓ (1mol / 90.08g) = 1.40x10⁻³ moles of H₃C-CH(OH)-COOH
To reach equivalence point, the student must add 1.40x10⁻³ moles of NaOH. These moles comes from:
1.40x10⁻³ moles of NaOH ₓ (1L / 0.0500moles NaOH) = 0.0280L of the 0.0500M NaOH =
28.0mL of the 0.0500M NaOH solutionwhat is the name of this molecule?
In movies about space, there is frequently a space battle scene where ships
explode in big fireballs. Why are these scenes unscientific?
O
A. The explosion would not be a fireball, but would point towards the closest gravity
source, a planet or star. They are only fireballs on Earth because we are already on a
gravity source.
B. None of these
C. There is no oxygen in space, so there can be no combustion.
OD. Space is very cold, there would not be enough heat energy for an explosion to occur.
-
The correct answer is C. There is no oxygen in space, so there can be no combustion.
Explanation:
Fire and flames are the result of a chemical process known as combustion. Moreover, for combustion to occur there are two essential elements. The first one is a fuel or a substance that releases energy and ignites, and the second one is an oxidant, which accepts electrons. This mix and reaction causes high temperatures and release of heat in the form of fire and flames.
This implies, that for fireballs or any other form of fire to exist there must be oxygen or any substance that replaces it. This does not occur in space because the levels of oxygen are extremely low, this means, at least oxygen is added fireballs are not possible in this context as there is no oxygen, and therefore no combustion (Option C).
Answer:
C.) There is no oxygen in space, so there can be no combustion.
Explanation:
I got it correct on founders edtell
Which of the choices is not a statement or direct application of the second law of thermodynamics? There are no 100% efficient heat engines. The change in internal energy of a system can be found by combining the heat energy added to a system minus the work done by the system. Heat energy naturally transfers from a high temperature substance to a low temperature substance. All natural processes tend toward states of increased entropy.
Answer:
The change in internal energy of a system can be found by combining the heat energy added to a system minus the work done by the system is not a direct application of second law of thermodynamics.
Explanation:
Second law of thermodynamics states that heat can be transfer spontaneously from high temperature to low temperature only.
The change in internal energy of a system can be found by combining the heat energy added to a system minus the work done by the system is not a direct application of second law of thermodynamics because according to the second law of thermodynamics it is impossible in any system for heat transfer from a source to completely convert to work done in a cyclical process( bring the system to its original stage after each cycle) in which the system then return to it's original stage.
One kilogram of butane (C4H10) is burned with 25 kg of air that is at 308C and 90 kPa. Assuming that the combustion is complete and the pressure of the products is 90 kPa, determine (a) the percentage of theoretical air used and (b) the dew-point temperature of the products.
Explanation:
Combustion of butane gives following reaction
C4H10 + 13/2 O2 → 5H20 + 4CO2
Therefore, One Kg of Butane consists of 1000/58 moles . That is 17.24 moles.
17.24 moles of butane reacts with (6.5×17.24) moles of O2 = 112.06 moles = 3.586 Kg O2.
Weight % of O2 in Air = 20 %
Mass of theoretical air used is 3.586×5 = 17.93 Kg = 71.72 %
The dew point temperature of H2O is :
D = (237.3×B)/(1-B)
B = ln(E/6.108)/17.27
E is vapor pressure at given temp.
At T = 30° C , E = 31.8 mm of Hg = 41.84 Milli Bars
B = 0.1114
D = 29.74°C
What products result from mixing aqueous solutions of Cr(NO3)2(aq) and NaOH(aq)? Question 10 options: Cr(OH)2(s), Na+(aq), and NO3−(aq) Cr(OH)2(s) and NaNO3(s) Cr2(OH)2(aq) and NaNO3(aq) Cr(OH)2(aq) and NaNO3(s) Cr(OH)2(s), N2(g), and H2O(l)
Answer:
Cr(OH)2(s), Na+(aq), and NO3−(aq)
Explanation:
Let is consider the molecular equation;
2NaOH(aq) + Cr(NO3)2(aq) -----> 2NaNO3(aq) + Cr(OH)2(s)
This is a double displacement or double replacement reaction. The reacting species exchange their partners. We can see here that both the sodium ion and chromium II ion both exchanged partners and picked up each others partners in the product.
Sodium ions and nitrate ions now remain in the solution while chromium II hydroxide which is insoluble is precipitated out of the solution as a solid hence the answer.
What mass of Si, in grams, can be produced from the reaction below starting with 225 g SiCl4 and 101 g Mg? SiCl4 + Mg Si + MgCl2 Given: 1 mol SiCl4 = 169.8963 g SiCl4 1 mol Mg = 24.3050 g Mg 1 mol Si = 28.0855 g Si
Answer:
[tex]m_{Si}=37.2gSi[/tex]
Explanation:
Hello,
In this case, for the undergoing balanced chemical reaction:
[tex]SiCl_4 + 2Mg \rightarrow Si + 2MgCl_2[/tex]
We must first identify the limiting reactant given the 225 g of SiCl4 and 101 g of Mg. Thus, we compute the available moles of SiCl4:
[tex]n_{SiCl_4}=225gSiCl_4*\frac{1molSiCl_4}{169.8963gSiCl_4}=1.324molSiCl_4[/tex]
Next, by using the 1:2 mole ratio between SiCl4 and Mg, we compute the moles of SiCl4 consumed by 101 g of Mg:
[tex]n_{SiCl_4}^{consumed}=101gMg*\frac{1molMg}{24.3050gMg} *\frac{1molSiCl_4}{2molMg} =2.08molSiCl_4[/tex]
Thus, since less moles of SiCl4 are available, we can infer it is the limiting reactant whereas the Mg is in excess. In such a way, the produced grams of Si are computed considering the 1:1 molar ratio between SiCl4 and Si:
[tex]m_{Si}=1.324molSiCl_4*\frac{1molSi}{1molSiCl_4} *\frac{28.0855gSi}{1molSi} \\\\m_{Si}=37.2gSi[/tex]
Best regards.
One of the nuclides in spent nuclear fuel is U-235, an alpha emitter with a half-life of 703 million years. How long will it take for an amount of U-235 to reach 24.0% of its initial amount? Express your answer in years to three significant figures. View Available Hint(s)
Answer:
1447584654 years or 1.44 billion years
Explanation:
From the formula;
0.693/t1/2=2.303/t log No/N
Where;
t1/2 = half life of the U-235 nuclides
No= amount of U-235 initially present
N= amount of U-235 present after a time t
t= time taken for N amount of U-235 to remain
Since N= 0.24No
Substituting values
0.693/703×10^6 = 2.303/t log No/0.24No
9.8578×10^-10 = 2.303/t log 1/0.24
9.8578×10^-10 = 1.427/t
t= 1.427/9.8578×10^-10
t= 1447584654 years
A cannonball made of iron has a volume of 121 cm3. What is the mass, in kilograms, of the cannonball? Express your answer to three significant figures and include the appropriate units.
Answer:the mass is 35456
Explanation:
because it works
The density has been the division of the mass to the volume of the substance. The mass of an iron cannonball of density 7.86 grams/cm³ is estimated to be 0.951 kilograms.
What is the relationship between mass and density?The mass (m) has been calculated by multiplying the density (D or ρ) and volume (V) of the iron cannonball. The measurement of the amount is called mass whereas the measurement of the space occupied by the substance volume is given as density.
The amount of the substance contained in a volume (milliliters, liters, and cubic centimeters) along with the density of the substance has been used to give mass. The mass can be estimated in kilograms, grams, milligrams, etc.
Given,
Density of iron cannonball (D) = 7.86 grams/cm³
Volume of cannonball (V) = 121 cm³
The formula to calculate mass is given as:
Density = mass ÷ volume
Mass = density × volume
Substituting values in the above formula, the mass of the iron cannonball in grams is calculated as:
mass = 7.86 grams/cm³ × 121 cm³
mass = 951.06 grams
Therefore, the iron cannonball with a density of 7.86 grams/cm³ has a mass of 0.951 kilograms.
Learn more about mass and density, here:
https://brainly.com/question/13799762
#SPJ2
Your question is incomplete, but most probably your full question was, A cannonball made of iron has a volume of 121 cm³. if the iron has a density of 7.86 g/cm³, what is the mass, in kilograms, of the cannonball?
AB2AB2 has a molar solubility of 3.72×10−4 M3.72×10−4 M. What is the value of the solubility product constant for AB2AB2? Express your answer numerically.
Answer:
Ksp = 2.06x10⁻¹⁰
Explanation:
For AB₂. solubility product constant, Ksp, is written as follows:
AB₂(s) ⇄ A²⁺ + 2Br⁻
Ksp = [A²⁺] [Br⁻]²
Molar solubility represents how many moles of AB₂ are soluble per liter of solution. and is obtained from Ksp:
AB₂(s) ⇄ A²⁺ + 2Br⁻
AB₂(s) ⇄ X + 2X
where X are moles that are soluble (Molar solubility)
Ksp = [X] [2X]²
Ksp = 4X³As molar solubility of the salt is 3.72x10⁻⁴M:
Ksp = 4X³
Ksp = 4(3.72x10⁻⁴)³
Ksp = 2.06x10⁻¹⁰True or False
1. Density is considered a chemical (i.e., not a physical) property. TRUE FALSE
2. When naming an ionic compound containing a transition element such as iron (Fe), the name must include a Roman numeral to indicate the charge of the metal ion. TRUE FALSE
3. The neutron was discovered about 20 years after the electron and proton because it has no charge (in order for it to be detected). TRUE FALSE
4. When we balance a chemical equation, we are observing the law of conservation of mass as well as the part of Dalton’s theory that atoms are neither created or destroyed in a chemical reaction TRUE FALSE
5. When a gas is heated up in a closed container, the kinetic energy of the molecules or atoms of the gas increase, which leads to a decrease in the pressure of the gas. TRUE FALSE
6. The amount of enthalpy (heat energy) for a reaction is directly proportional to the amount (number of moles or grams) of the reactants. TRUE FALSE
7. The combined gas law works for any gas (i.e., you do not need to know the chemical formula). TRUE FALSE
8. A balloon with 10.0 g of CO2 gas will have more molecules than a 10.0 g sample of NO gas. TRUE FALSE
9. Unless a sample is at absolute zero (kelvins), the particles in the sample will have kinetic energy and have some kind of motion. TRUE FALSE
Answer:
1. False
2. True
3. True
4. True
5. True
6. True
7. True
8. False
9. True
Explanation:
Density is a physical property since its measurement does not involve any chemical process.
Since transition elements exhibit variable oxidation states, the actual oxidation state of the transition element must be specified in the compound.
Due to the fact that neutron has no charge, it was discovered by Chadwick long after the electron and proton were discovered.
The balancing of chemical reaction equations is a demonstration that atoms are neither created no destroyed. It also shows that mass is neither created nor destroyed in chemical reactions.
When a gas is heated, it expands. Its volume and its kinetic energy increases. Since volume and pressure are inversely proportional (Boyle's law) the pressure decreases.
Enthalpy is said to be an extensive property. This implies that the magnitude of change in enthalpy is known to depend on the amount of reactants that is actually reacted.
The combined gas law is applicable to all ideal gas systems irrespective of their individual chemical formulas.
10g of CO2 contains 0.227 moles of CO2 while 10g of NO contains 0.33 moles of NO hence 10.0 g of NO will contain more molecules than 10.0g of CO2.
If a sample is not at absolute zero, the particles are known to possess kinetic energy which decreases continuously until absolute zero is attained.
A chemist adds of a M sodium carbonate solution to a reaction flask. Calculate the millimoles of sodium carbonate the chemist has added to the flask. Round your answer to significant digits.
Answer:
256 milimoles of Sodium Carbonate are in the flask
Explanation:
The chemist adds 180mL of a 1.42M sodium carbonate solution.
Molarity is an unit of concentration in chemistry defined as the ratio between moles of solute (Sodium Carbonate, in this case) per liter of solution.
A 1.42M solution contains 1.42 moles of Sodium carbonate in 1L of the solution.
As you have 180mL = 0.180L, moles of sodium carbonate you have are:
0.180L × (1.42 moles Sodium Carbonate / 1L) = 0.2556 moles of sodium carbonate
1000milimoles are equal to 1mole. 0.2556 moles are:
0.2556 moles × (1000 milimoles / 1 mole) =
256 milimoles of Sodium Carbonate are in the flaskWhy are antiparallel beta sheets more stable than parallel beta sheets?
Answer:
The side chains of the amino acids alternate above and below the sheet
Explanation:
Hydrogen bonds are formed between the amine and carbonyl groups across strands. ... Antiparallel ß sheets are slightly more stable than parallel ß sheets because the hydrogen bonding pattern is more optimal.
An energy of 13.6 eV is needed to ionize an electron from the ground state of a hydrogen atom. Selecting the longest wavelength that will work from the those given below, what wavelength is needed if a photon accomplishes this task
Answer:
The wavelength is [tex]\lambda = 91nm[/tex]
Explanation:
From the question we are told that
The energy required is [tex]E = 13.6 \ eV[/tex]
This energy needed in form of a photon can be mathematically represented as
[tex]E = \frac{h * c }{\lambda }[/tex]
where h is the Planck constant with a value [tex]h = 4.1357 * 10{-15} eV \cdot sec[/tex]
and c is the speed of light which is
substituting values
[tex]13.6 eV = \frac{ 4.1357 * 10^{-15} eV * 3.0*10^8 }{\lambda }[/tex]
= > [tex]\lambda = 9.1*10^{-8}[/tex]
[tex]\lambda = 91nm[/tex]
In the laboratory you are asked to make a 0.694 m copper(II) iodide solution using 455 grams of water. How many grams of copper(II) iodide should you add
Answer:
100.2g of CuI₂ you must add
Explanation:
Molality, m, is defined as the ratio between moles of solute and kg of solvent.
In the problem, you have a 0.694m of copper (II) iodide -CuI₂, molar mass: 317.35 g/mol-. That means there are 0.694 moles of CuI₂ per kg of water.
As you have 455g = 0.455kg of water -solvent-, moles of CuI₂ are:
0.455kg ₓ (0.694 moles CuI₂ / kg) = 0.316 moles of CuI₂
Using molar mass, grams of CuI₂ in the solution are:
0.316moles CuI₂ ₓ (317.35g / mol) =
100.2g of CuI₂ you must addWhat is the empirical formula for the compound: C8H8S2?
Answer:
Empirical formula = C4H4SExplanation:
The subscripts in a formula determine the ratio of the moles of each element in the compound. To convert this formula to the empirical formula, divide each subscript by 2. This is similar to reducing a fraction to its lowest denominator.
Solid sodium oxide and gaseous water are formed by the decomposition of solid sodium hydroxide (NaOH) .
Write a balanced chemical equation for this reaction.
Answer:
2NaOH(s) → Na₂O(s) + H₂O(g)
Hope that helps.
Calculate the amount of heat energy, in kJ, needed to increase the temperature of 200g of water by 300 C.
Answer:
Q = 246 kJ
Explanation:
It is given that,
Mass of water, m = 200 g
Let initial temperature, [tex]T_i=5^{\circ}[/tex]
Final temperature of water, [tex]T_f=300^{\circ} C[/tex]
We know that the specific heat capacity of water, [tex]c=4.18\ J/g-^{\circ} C[/tex]
So, the heat energy needed to raise the temperature is given by :
[tex]Q=mc\Delta T\\\\Q=200\times 4.18\times (300-5)\\\\Q=246620\ J[/tex]
or
Q = 246 kJ
So, the heat energy of 246 kJ is needed.
Determine the cell notation for the redox reaction given below.
Sn(s) + 2H+(aq) ⟶ Sn2+(aq) + H2(g)
a. H+(aq) | H2(g) | Pt ∥ Sn(s) | Sn2+(aq)
b. H2(g) | H+(aq) | Pt ∥ Sn2+(aq) | Sn(s)
c. Sn2+(aq) | Sn(s) ∥ H2(g) | H+(aq) | Pt
d. Sn(s) | Sn2+(aq) ∥ H+(aq) | H2(g) | Pt
e. Sn(s) | H2(g) ∥ Sn2+(aq) | H+(aq) | Pt
Answer:
The correct answer is d. Sn(s) | Sn²⁺(aq) ∥ H⁺(aq) | H₂(g) | Pt
Explanation:
The half reactions are:
2H⁺(aq) + 2 e- ⟶ H₂(g) (reduction)
Sn(s) ⟶ Sn²⁺(aq) + 2 e- (oxidation)
In the cell notation, there are two electrodes in which are separated the reduction reaction from the oxidation reaction. In the left electrode occurs the oxidation reaction (anode) while in the right electrode occurs the reduction reaction (cathode). The general form of the cell notation is the following:
anode reaction∥ cathode reaction
where the two bars ( ∥ ) represent the physical barrier between the electrodes. A single bar ( | ) is used to represent a phase separation.
In this redox reaction, the half reaction of the anode is Sn(s) ⟶ Sn²⁺(aq) + 2 e-; whereas the half reaction of the cathode is 2H⁺(aq) + 2 e- ⟶ H₂(g).
The componens are written in order according to the half reaction. Since Sn²⁺ and H⁺ ions are in solution, a platinum electrode is used and represented as Pt. Thus, the cell notation is:
Sn(s) | Sn²⁺(aq) ∥ H⁺(aq) | H₂(g) | Pt
Draw the structural formula of the principal organic product formed when ethyl benzoate is treated with C6H5MgBr (two equivalents), then HCl/H2O.
Answer:
Ph3OH
Explanation:
The reaction is between ethyl benzoate (PhCOOC2H5) and a Grignard reagent PhMgBr(C6H5MgBr).
The first step in the reaction mechanism is that the ethyl benzoate is converted to PhCOPh by the first molecule of Grignard reagent.
The second molecule of Grignard reagent now converts PhCOPh to Ph3O^-. In the presence of acid, Ph3O^- is now protonated to yield Ph3OH which is the major organic product of the reaction.
See image attached for more details.
Does the number of moles of products increase, decrease, or remain the same when each of the following equilibria is subjected to an increase in pressure by decreasing the volume?
1- CO(g)+H2O(g)⇌CO2(g)+H2(g)
2- 2CO(g)⇌C(s)+CO2(g)
3- N2O4(g)⇌2NO2(g)
_______________________________________________
Ethyl acetate, a solvent used in many fingernail-polish removers, is made by the reaction of acetic acid with ethanol:
CH3CO2H(soln)Aceticacid +C2H5OH(soln)Ethanol⇌CH3CO2H(soln)Ethylacetate+H2O(soln)ΔH∘=−2.9kJ
Part A
Does the amount of ethyl acetate in an equilibrium mixture increase or decrease when the temperature is increased?
increase
decrease
Part B
How does Kc change when the temperature is decreased? Justify your answers using Le Chatelier's principle.
How does change when the temperature is decreased? Justify your answers using Le Chatelier's principle.
As the temperature is decreased, the reaction shifts from left to right. The product concentrations increase, and the reactant concentrations decrease. This corresponds to an increase in Kc.
As the temperature is decreased, the reaction shifts from right to left. The product concentrations decrease, and the reactant concentrations increase. This corresponds to an decrease in Kc.
As there is neither products no reactants in gas state the temperature does not shift the reaction. So decrease in temperature does not change Kc.
________________________________________________________
A platinum catalyst is used in automobile catalytic converters to hasten the oxidation of carbon monoxide:
2CO(g)+O2(g)⇌Pt2CO2(g)ΔH∘=−566kJ
Suppose that you have a reaction vessel containing an equilibrium mixture of CO(g), O2(g), and CO2(g). Under the following conditions, will the amount of CO increase, decrease, or remain the same after each of the following changes?
A platinum catalyst is added.
increase
decrease
remain the same
The temperature is increased.
increase
decrease
remain the same
The pressure is increased by decreasing the volume.
increase
decrease
remain the same
The pressure is increased by adding argon gas.
increase
decrease
remain the same
The pressure is increased by adding gas.
increase
decrease
remain the same
Answer:
1-remain the same
2- remain the same
3-decrease
--------------------------
- decrease
- As the temperature is decreased, the reaction shifts from left to right. The product concentrations increase, and the reactant concentrations decrease. This corresponds to an increase in Kc.
--------------------------------
1- decrease
2-increase
3-decrease
4-remain the same
5-decrease
Explanation:
According to Le Chateliers principle, an increase in the volume of a gaseous system at equilibrium will shift the equilibrium position towards the side in which there are less volumes. Hence the answers written. When there is no change in volume, the number of moles of products remain the same.
-------------------------------
For an exothermic reaction, increasing the temperature shifts the equilibrium to the lefthand side.
When temperature is decreased, the equilibrium position will shift towards the right according to Le Chateliers principle
---------------------
Addition of a catalyst aids the reaction in which CO is consumed to proceed faster hence CO decreases in the system.
Since the reaction is exothermic, according to Le Chateliers principle, when the temperature is increased, the equilibrium position shifts towards the lefthand side and more CO is now present in the system.
When the pressure of the system is increased, the equilibrium position will shift towards the right hand side and more CO is converted to products hence its concentration in the system decreases.
Addition of argon gas has no effect on the equilibrium position since it does not participate in the reaction. However, addition of the reactant gases increases the rate of reaction and shifts the equilibrium position towards the right hand side thus decreasing the concentration of CO in the system.
Which, if any, of the two molecular geometries is likely to be polar if the outer atoms are identical and there is a difference in electronegativity between the central atom and the outer atoms
Answer:
Polar molecules are not symmetrical
Explanation:
Even though the structures of the molecules involved were not shown in the question, but I will proceed to give a general explanation of the conditions that describe a polar molecule.
First of all, symmetrical molecules are non-polar and asymmetrical molecules are polar. This is the reason why CF4 will be a nonpolar molecule but H2O will be a polar molecule. Some symmetrical molecules may may posses polar bonds or dipoles but these dipoles eventually cancel out since the molecule is symmetrical in nature.
Summarily, if a molecule possess the same type of atoms attached to the central atom with some symmetry axes, like C3, C4 etc., we will end up with a non polar molecule but if we have a nonplanar molecule, then we will end up finding it to be polar.
Question 4
1 points
Save Answer
A solution is prepared at 25°C that is initially 0.42 M in an "X" base, a weak base with Kb=7.4X10^-4, and 0.42 M in conjugate acid "HX". Calculate the pH of the
solution. Round your answer to 2 decimal places.
(Hint: pkw=pka + pkb)
A Moving to another question will save this response.
< Question 4 of 12>
Answer:
pH = 10.87
Explanation:
You can find pH of a buffer (Mixture of a weak base, X, and its conjugate acid, HX) by using H-H equation:
pH = pKa + log [X] / [HX]
pKb is -log Kb = 3.13
Using Hint pKw = pKa + pKb (pKw = 14)
pKw = pKa + pKb
14 - 3.13 = pKa
10.87 = pKa
Replacing in H-H equation:
pH = 10.87 + log [0.42M] / [0.42]
pH = 10.87 + log 1
pH = 10.87A civil engineer designs mostly:
A. building structures.
B. computer parts.
C. new foods.
D. technology that flies.
The height of a column of mercury in a closed-end manometer is 13.2 cm. What is the pressure of the gas in torr
Answer:
[tex]P_{gas}=131.96torr[/tex]
Explanation:
Helo,
In this case, the pressure must be computed as follows:
[tex]P_{gas}=gh\rho _{Hg}[/tex]
Which is using the density of mercury (13.6 g/mL) and its height, thus, we obtain (using the proper units):
[tex]P_{gas}=9.8\frac{m}{s^2}*(13.2cm *\frac{1m}{100cm} )*(13.6\frac{g}{cm^3}*\frac{1kg}{1000g}*\frac{1x10^6cm^3}{1m^3} )\\\\P_{gas}=17592.96Pa*\frac{760torr}{101325Pa} \\\\P_{gas}=131.96torr[/tex]
Best regards.
Balance the following skeleton reaction and identify the oxidizing and reducing agents: Include the states of all reactants and products in your balanced equation. You do not need to include the states with the identities of the oxidizing and reducing agents.
CrO_4^2- (aq) + N_2O(g) rightarrow Cr^3+ (aq) + NO(g) [acidic]
The oxidizing agent is:_______.
The reducing agent is:_______.
Answer:
Oxidizing agent - CrO4^2-
Reducing agent- N2O
Explanation:
Let us look at the equation closely;
CrO4^2- (aq) + 3N2O(g) ------------> Cr^3+ (aq) + 3NO(g) [acidic]
The reduction half equation is;
CrO4^2- (aq) + 3e -------->Cr^3+ (aq)
Oxidation half equation is;
3N2O(g) ------>3 NO(g) +3 e
Note that the oxidizing agent participates in the reduction half equation while the reducing agent participates in the oxidation half equation as seen above.
A sample of drinking water contains 668 ppm of lead. How many grams of lead are there in 100.0 g of this water?
Answer:
0.0668g
Explanation:
Step 1: Given data
Concentration of lead: 668 ppm (mg/kg)
Mass of water: 100.0 g
Step 2: Convert the mass of water to kilograms
We will use the relationship 1 kg = 1,000 g.
[tex]100.0g \times \frac{1kg}{1,000g} = 0.1000kg[/tex]
Step 3: Calculate the mass of lead in 0.1000 kg of water
There are 668 mg of Pb in 1 kg of water.
[tex]0.1000kgWater \times \frac{668mgPb}{1kgWater} = 66.8mgPb[/tex]
Step 4: Convert the mass of Pb to grams
We will use the relationship 1 g = 1,000 mg.
[tex]66.8mg \times \frac{1g}{1,000mg} = 0.0668g[/tex]
A spinning turbine can generate electricity only in the form of a/an _______ current.
Of all the alternative energy technologies presented in this section, only solar panels produce a/an _______ current.
Answer:
The correct answer is - alternating and direct, in order.
Explanation:
Alternating current is is type of electric current that is characterized by the direction of the flow of electrons in continuously switches its directs in opposite manner at regular cycles. While direct current or DC is flow of the electrons that move from starting to end in one direction.
Spinning turbines always leads to the alternating electric current while only solar energy produces the direct current with the help of the solar panels.
Thus, the correct answer is - alternating and direct, in order.
Answer:
1. alternating
2. direct
3. The sun heats up the atmosphere as Earth spins, creating areas of high and low temperature. This temperature difference causes wind to start moving through convection, which can then drive a wind turbine to produce electricity.
Explanation:
From Penn