The heat of formation of the given reaction is -56.4 kJ/mol.
What is Heat?
Heat is a form of energy that flows from a hotter object to a colder object. It is a type of energy transfer that occurs due to a temperature difference between two objects. The direction of heat flow is always from the object with higher temperature to the object with lower temperature until they reach thermal equilibrium.
The heat of formation of a compound is defined as the enthalpy change when one mole of the compound is formed from its constituent elements in their standard states at a given temperature and pressure. The standard state of an element is its most stable form at 1 atm pressure and a specified temperature.
Using the heat of formation values from standard tables, we can calculate the heat of formation of the products and reactants in the given reaction as follows:
Heat of formation of NO2 = -33.2 kJ/mol
Heat of formation of NO = +90.3 kJ/mol (since NO is an unstable gas at room temperature, we use the heat of formation of NO at 298 K instead of the standard heat of formation)
Heat of formation of O2 = 0 kJ/mol
Therefore, the heat of formation of the given reaction is:
ΔHf = Σ(heat of formation of products) - Σ(heat of formation of reactants)
ΔHf = [2(-33.2 kJ/mol)] - [2(90.3 kJ/mol) + 0 kJ/mol]
ΔHf = -56.4 kJ/mol
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in a sample of 'a' found today, there are 128,000 atoms. if the halflife of 'a' is 5,000 years, in what year will the sample have 8,000 atoms?
In the year 20,002.5, the sample of 'a' will have 8,000 atoms, after passing through approximately 4 half-lives of 5,000 years each.
To solve the problem, we can use the equation for half-life:
T = (ln(N₀/N))/λ
where T is the half-life, N₀ is the initial number of atoms, N is the final number of atoms, and λ is the decay constant. Rearranging the equation to solve for N gives:
N = N₀e^(-λT)
We can use this equation to solve for the year when the sample will have 8,000 atoms.
Let's plug in the values we know:
N₀ = 128,000N = 8,000T = 5,000 years
λ = ln(2)/THalf-life (T) is 5,000 years.
Thus, decay constant λ is given by:
λ = ln(2)/T= ln(2)/5000= 0.00013862789.
Now we can plug in the values and solve for the year:N = N₀e^(-λT)8000 = 128,000e^(-0.00013862789T)
Divide both sides by 128,000:0.0625 = e^(-0.00013862789T)Take the natural logarithm of both sides:-
2.77259 = -0.00013862789TT = 20,002.5 years ago.
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Which feature of a molecule can be determined from its NMR spectrum?
Among the features that can be determined from its NMR spectrum are: number of distinct proton environments, relative number of protons in each environment, chemical shift values for each environment, and splitting patterns.
The proton (1H) nuclear magnetic resonance (NMR) spectrum of a molecule helps to identify several features of that molecule.
The number of distinct proton environments is equivalent to the number of different kinds of protons in the molecule. For example, in a molecule with three different types of protons, such as [tex]CH3CH2OH[/tex] (ethanol), there will be three separate peaks in the spectrum.
The relative number of protons in each environment, which is proportional to the area under each peak, provides information on the molecule's composition.
The chemical shift values for each environment are a measure of the strength of the magnetic field felt by the protons in that environment. The magnetic field strength is influenced by the neighboring atoms and functional groups.
Therefore, the chemical shift can be used to infer information about the molecule's electronic structure and functional groups. The splitting patterns in a peak provide information about the number of neighboring protons. This helps to infer the connectivity of the molecule.
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calculate the number of moles of NaCl contained in 0.500 L of a 1.5M solution
Answer:
mol = 0.75
Explanation:
M = mol/L
1.5 = mol/.5
mol = 0.75
you are asked to write your name on a suitable surface, using a piece of chalk that is pure calcium carbonate, caco3. how could you calculate the number of carbon atoms in your signature?
You can calculate the molar mass of CaCO3, which is equal to the sum of the atomic masses of calcium, carbon, and three oxygen atoms.
The atomic mass of calcium is 40.078 g/mol, carbon is 12.011 g/mol, and oxygen is 15.999 g/mol.
So, the molar mass of CaCO3 is:
Molar mass of CaCO3 = (1 × 40.078 g/mol) + (1 × 12.011 g/mol) + (3 × 15.999 g/mol)
= 100.086 g/mol
The molar mass of CaCO3 can also be calculated using the atomic weights of the elements, which are found on the periodic table. Once you know the molar mass of CaCO3, you can calculate the number of moles of CaCO3 used to write your name, based on the mass of chalk used.
Method 2:You can use the Avogadro constant to convert the number of moles of CaCO3 used to write your name into the number of formula units of CaCO3. Since each formula unit of CaCO3 contains one carbon atom, you can then determine the number of carbon atoms in your signature.
Method 3:Alternatively, you can use the stoichiometry of the reaction that occurs when CaCO3 is used to write on a surface. When CaCO3 is used to write on a surface, it reacts with carbon dioxide (CO2) in the air to form calcium oxide (CaO) and carbon dioxide (CO2).
The balanced chemical equation for this reaction is:
CaCO3(s) + CO2(g) → CaO(s) + CO2(g) + Heat
From this equation, you can see that each formula unit of CaCO3 reacts with one molecule of CO2 to produce one carbon atom in the form of CO2. Therefore, the number of carbon atoms in your signature is equal to the number of molecules of CO2 produced during the reaction. To calculate the number of molecules of CO2 produced, you need to know the mass of CaCO3 used to write your name and the volume of CO2 produced. The volume of CO2 can be measured using a gas syringe or a gas collection method. Once you know the volume of CO2, you can convert it to moles of CO2 using the ideal gas law, and then to molecules of CO2 using Avogadro's number.
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What is the balanced equation for
Solid calcium fluoride decomposes to form calcium metal and fluorine gas?
The balanced equation for the given reaction is:
CaF2(s) → Ca(s) + F2(g)
This equation indicates that one molecule of calcium fluoride (CaF2) decomposes into one molecule of calcium (Ca) and one molecule of fluorine gas (F2). The equation is balanced because the number of atoms of each element is equal on both sides of the equation.
which of the following statements correctly describe standard electrode potentials? in what way must half-reactions and/or electrode potentials be manipulated when writing a balanced equation for a redox reaction? multiple select question. by convention, standard electrode potentials are quoted as reduction potentials. the half-reaction for the anode must be reversed when writing the balanced equation for the overall reaction. the sign for the anode potential must be reversed in order to to use the equation ecell
To accomplish this, the half-reaction with the smallest number of electrons may be multiplied. When writing the balanced equation, the half-reaction for the anode should be reversed to account for the oxidation occurring at the anode. Finally, to use the equation ecell, the sign of the anode potential must be reversed.
When answering questions on the Brainly platform, it is important to be factually accurate, professional, and friendly. One should be concise and avoid providing extraneous amounts of detail. Typos and irrelevant parts of the question should be ignored. The answer to the given question is as follows:By convention, standard electrode potentials are quoted as reduction potentials. The half-reaction for the anode must be reversed when writing the balanced equation for the overall reaction. The sign for the anode potential must be reversed to use the equation ecell.Standard electrode potentials are measured for half-reactions in their standard states, such as solutions of 1 mol/L and gases at a pressure of 1 atm. It indicates the ability of a half-reaction to accept electrons, with the half-reaction with the greatest reduction potential being the strongest oxidizing agent.When writing a balanced equation for a redox reaction, half-reactions and/or electrode potentials must be manipulated in order to balance the number of electrons transferred. Since the electrons must cancel out in the overall reaction, one half-reaction should be multiplied to match the number of electrons in the other half-reaction.
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you were given the values 0.2107, 2.253, 3.392, and 17.58 as the van der waals parameter a for the gases co2, ch3cn, ne, and ch4 but not the correspondence of the values to the compounds. what a value shoud be assigned to ch3cn?
The van der Waals parameter 'a' value that should be assigned to CH3CN is 17.58.
To determine the van der Waals parameter (a) value for CH3CN, we must first understand the significance of the van der Waals equation and the parameter "a" itself. The van der Waals equation accounts for the non-ideal behavior of gases by considering the finite size of gas particles and the attractive forces between them.
The "a" parameter represents the strength of the attractive forces between the gas particles.
Generally, larger and more polarizable molecules have higher "a" values due to stronger attractive forces. Now, let's compare the four given gases - CO2, CH3CN, Ne, and CH4.
1. CO2 (carbon dioxide) is a linear, non-polar molecule, but it has a relatively large molecular weight.
2. CH3CN (acetonitrile) is a polar molecule with a cyano group (-C≡N) and a methyl group (-CH3), leading to stronger attractive forces.
3. Ne (neon) is a noble gas with weak attractive forces due to its small size and low polarizability.
4. CH4 (methane) is a non-polar molecule with a smaller size compared to CO2 and CH3CN.
Based on this information, we can roughly rank the gases in terms of their expected "a" values: CH3CN > CO2 > CH4 > Ne.
Now, let's match the given values (0.2107, 2.253, 3.392, 17.58) to the compounds:
1. Ne has the smallest "a" value, so it corresponds to 0.2107.
2. CH4 has the next smallest "a" value, so it corresponds to 2.253.
3. CO2 has a larger "a" value than CH4, so it corresponds to 3.392.
4. CH3CN has the largest "a" value, so it corresponds to 17.58.
Thus, the "a" value assigned to CH3CN should be 17.58.
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Equilibrium is established in a reversible reaction when:
the [product] = [reactants]
product is no longer produced
rate of reaction of products = rate of reaction of reactants
all the reactants dissolve or dissociate
A reversible chemical reaction is said to be in equilibrium when the forward and reverse reactions happen at the same rate and there is no total change in the concentrations of the reactants and products.
The concentrations of the reactants and products achieve a steady state at equilibrium, where the rates of the forward and reverse reactions are equal.
Although the concentration of the reactants and products is constant once the equilibrium is reached, this does not indicate that all of the reactants have been converted to products or that the production of products has ceased.
The concentrations of the reactants and products are no longer changing over time because the forward and backward reaction rates have instead equaled out.
In other words, when a system reaches equilibrium, it is in a dynamic state where both forward and backward reactions are still taking place but the concentrations of the reactants and products are constant. This indicates that the system is in equilibrium and the ratio of reactant to product concentrations is stable.
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Answer:
rate of reaction of products = rate of reaction of reactants
Explanation:
i got it right
Our atmosphere is made up of 78% N2, 21% O2, and 1% other gases. What is the partial pressure of N2 when atmospheric pressure is 0.980 atm?
Answer: 0.7644 atm
Explanation:
Given,
Total atmospheric pressure= 0.980atm
Percentage of N₂=78%=0.78
Partial Pressure of N₂=Total atmospheric pressure*Percentage of N₂
=0.980 atm × 0.78
=0.7644 atm
which energy difference in the energy profile below corresponds to the activation energy for the forward reaction?
The activation energy of the forward reaction is represented by the energy difference between X and Y*, and the activation energy of the backward reaction is represented by the energy difference between Y and Y*. So, for the forward reaction, the correct response is X-Y*, and for the opposite reaction, it is Y-Y*.
The height from the valley to the apex serves as a visual cue in an energy profile graphic to indicate the activation energy. Based on the need, the valley may hold a reagent or a product.
Energy ––– A chain of reactions The activation energy of the component is represented by the red line, while the activation energy of the product is represented by the blue line.
As a result, the reactant's activation energy is x and the product's activation energy is x+y.
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the salt obtained from the combination of the weak acid cyanic acid, hcno, and the weak base ammonia, nh3, is used to make an aqueous solution. is the solution acidic, basic, or neutral? select the correct answer below: neutral acidic basic there is not enough information.
The aqueous solution of the salt formed from the combination of a weak acid and a weak base is neutral. Option A is correct.
The salt obtained from the combination of a weak acid and a weak base can lead to a neutral, acidic, or basic solution depending on the relative strengths of the acid and base involved. In this case, the weak acid cyanic acid (HCNO) and the weak base ammonia (NH₃) react to form the salt ammonium cyanate (NH₄CNO), which can dissociate in water as follows:
NH₄CNO(s) + H₂O(l) → NH₄⁺(aq) + CNO⁻(aq)
Since ammonium ion (NH₄⁺) is the conjugate acid of the weak base ammonia and cyanate ion (CNO⁻) is the conjugate base of the weak acid cyanic acid, their tendency to either accept or donate protons (H⁺) will depend on their respective acid/base strengths.
In this case, because both the acid and base are weak, the salt will be a neutral salt, which means it will not affect the pH of the aqueous solution. Therefore, the aqueous solution of ammonium cyanate is expected to be neutral. In summary, the salt generated by combining a weak acid with a weak base is neutral in aqueous solution. Option A is correct.
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which of the following best explains the pattern in no concentration? (a) no is a secondary pollutant with a long residence time in the atmosphere. (b) no does not play a significant role in smog formation. (c) no is formed in the lower atmosphere in the morning by the rising sun. (d) no is produced by rush-hour traffic and is quickly oxidized in the atmosphere. (e) no is quickly absorbed by plants and converted to sugars.
(a) The statement that "NO is a secondary pollutant with a long residence time in the atmosphere" suggests that NO may accumulate in the atmosphere over time and contribute to poor air quality. This could be a potential explanation for high levels of NO in areas with poor air quality.
(b) The statement that "NO does not play a significant role in smog formation" suggests that NO may not be a key contributor to poor air quality in areas with smog. This could be a potential explanation for low levels of NO in areas with smog.
(c) The statement that "NO is formed in the lower atmosphere in the morning by the rising sun" suggests that NO may be more prevalent in the atmosphere during certain times of day. This could be a potential explanation for fluctuations in NO concentrations over the course of a day.
(d) The statement that "NO is produced by rush-hour traffic and is quickly oxidized in the atmosphere" suggests that NO may be more prevalent in the atmosphere during rush hour. This could be a potential explanation for higher levels of NO in urban areas during rush hour.
(e) The statement that "NO is quickly absorbed by plants and converted to sugars" suggests that NO may be removed from the atmosphere by vegetation. This could be a potential explanation for lower levels of NO in areas with high vegetation cover.
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3. How many mL of a 0.235 M solution of sulfuric acid is required to neutralize
30.0 mL of 0.260 M potassium hydroxide?
The balanced chemical equation for the neutralization reaction between sulfuric acid and potassium hydroxide is:
H2SO4(aq) + 2KOH(aq) → K2SO4(aq) + 2H2O(l)
From the equation, we can see that one mole of sulfuric acid reacts with two moles of potassium hydroxide. Therefore, we need to calculate the number of moles of potassium hydroxide present in the 30.0 mL of 0.260 M solution:
0.260 mol/L x 0.0300 L = 0.00780 mol KOH
Since the stoichiometric ratio of sulfuric acid to potassium hydroxide is 1:2, we need twice as many moles of sulfuric acid to neutralize the potassium hydroxide:
2 x 0.00780 mol = 0.0156 mol H2SO4
Finally, we can calculate the volume of the 0.235 M sulfuric acid solution required to provide 0.0156 moles of H2SO4:
0.0156 mol / 0.235 mol/L = 0.0664 L = 66.4 mL
Therefore, 66.4 mL of the 0.235 M sulfuric acid solution is required to neutralize 30.0 mL of 0.260 M potassium hydroxide.
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when the balancing of the equation for the reaction, taking place in acidic media is properly completed, what is the sum of all the coefficients in the equation?
The sum of all the coefficients of the reaction MnO⁴⁻ + SO₃²⁻ → MnO₂ + SO₄²⁻ after balancing is found to be 16.
Here, is the unbalanced equation ('skeleton equation') of the chemical reaction. All reactants and products must be known. For a better result write the reaction in ionic form.
MnO⁴⁻ + SO₃²⁻ → MnO₂ + SO₄²⁻
Firstly, we balanced the not oxygen and hydrogen compounds by adding the required coefficient in from the the respective element of the reaction in the acidic medium.
Now, then we balance the oxygen atom by adding the water molecules on the opposite side of the required side of the reaction.
It is to be noted that we are using H₂O molecule and OH⁻ for balancing hydrogen molecules because it is in the acidic medium.
Now, the final reaction is,
2MnO₄⁻ + 3Mn²⁺ + 4OH⁻ → 5MnO₂ + 2H₂O
Now, the sum of all coefficients is 16.
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Complete question - when the balancing of the equation for the reaction,
MnO⁴⁻ + SO₃²⁻ → MnO₂ + SO₄²⁻ taking place in acidic media is properly completed, what is the sum of all the coefficients in the equation?
Answer the following question in the attachment please for homework that is due tomorrow
Answer:
Details on attachment.
Explanation:
See attached worksheet.
you perform an electrochemical reaction in which 0.800 mol of cu are reduced to solid cu . how many coulombs of charge are transferred?
The number of coulombs of charge transferred is 32220 C
When you perform an electrochemical reaction in which 0.800 mol of Cu are reduced to solid Cu, the number of coulombs of charge transferred can be calculated using Faraday's constant. The answer is 32220 C (coulombs).Explanation:
Given: The amount of Cu reduced to solid Cu = 0.800 mol
The amount of charge transferred can be calculated using Faraday's constant.
Faraday's constant = 96500 C mol^-1
Amount of charge transferred = n x FWhere,
n = Number of moles of electrons transferred.
F = Faraday's constant.Number of moles of electrons transferred
= 2 [Since the Cu ion gains 2 electrons to form Cu]Amount of charge transferred
= 2 x 96500 C mol^-1
= 193000 C [Or 1 F = 96500 C]Amount of charge transferred when 0.800 mol of Cu is reduced to solid Cu
= 193000 x 0.800 = 154400 C or 1.54 x 10^5 C (Approximately).
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How many kJ of heat are required to melt a 50.0-g popsicle at 0°C?
Assume the popsicle has the same molar mass and enthalpy of fusion
as water.
Answer: 16.7 KJ of heat
Explanation:
The heat required to melt the popsicle can be calculated using the equation:
q = nΔH
where q is the heat required, n is the number of moles of the substance being melted, and ΔH is the enthalpy of fusion.
To find the number of moles of the popsicle, we need to divide the mass by the molar mass:
n = m/M
where m is the mass of the popsicle and M is the molar mass. Since the popsicle has the same molar mass as water (18.0 g/mol), we have:
n = 50.0 g / 18.0 g/mol = 2.78 mol
The enthalpy of fusion of water is 6.01 kJ/mol, so we can calculate the heat required as:
q = nΔH = 2.78 mol x 6.01 kJ/mol = 16.7 kJ
Therefore, 16.7 kJ of heat are required to melt a 50.0-g popsicle at 0°C.
How many moles of O2 form when 1.0 mole of KCIO3 decomposes?
The balanced chemical equation for the decomposition of KCIO3 is:
2 KClO3 → 2 KCl + 3 O2
From the equation, it can be seen that for every 2 moles of KCIO3 that decompose, 3 moles of O2 are formed. Therefore, to determine the number of moles of O2 formed when 1.0 mole of KCIO3 decomposes, we need to use the mole ratio of KCIO3 to O2.
The mole ratio of KCIO3 to O2 is 2:3 (from the balanced chemical equation), which means that for every 2 moles of KCIO3 that decompose, 3 moles of O2 are formed. Therefore, to find the number of moles of O2 formed when 1.0 mole of KCIO3 decomposes, we can use the following proportion:
2 moles KCIO3 / 3 moles O2 = 1 mole KCIO3 / x moles O2
Solving for x, we get:
x = (3 moles O2)(1 mole KCIO3) / (2 moles KCIO3) = 1.5 moles O2
Therefore, when 1.0 mole of KCIO3 decomposes, 1.5 moles of O2 are formed.
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if 2.00 mol of carbon dioxide and 1.5 mol of hydrogen are placed in a5.00 l vessel and equilibrium is established, what will be the concentration of carbonmonoxide?7)
The concentration of carbon monoxide is also [tex]x = 0.0371\ \mathrm{M}$.[/tex]The balanced chemical equation for the reaction is:
[tex]$\mathrm{CO_2 + 4H_2 \rightleftharpoons CH_4 + 2H_2O}$[/tex]
The equilibrium expression for the reaction is:
[tex]$K_c = \dfrac{[CH_4][H_2O]^2}{[CO_2][H_2]^4}$[/tex]
At equilibrium, let the concentration of CO2 be $x$,, the concentration of CH4 be $y$, and the concentration of H2 be $z$.
Initial concentrations:
[tex]$[CO_2] = 2.00\ \mathrm{mol}/5.00\ \mathrm{L} = 0.400\ \mathrm{M}$[/tex]
[tex]$[H_2] = 1.50\ \mathrm{mol}/5.00\ \mathrm{L} = 0.300\ \mathrm{M}$[/tex]
[tex][CH_4] = 0\ \mathrm{M}$ (initially)[/tex]
[tex][H_2O] = 0\ \mathrm{M}$ (initially)[/tex]
At equilibrium, we know that:
[tex]y = [CH_4] = 2x$[/tex]
[tex]2y = [H_2O]$[/tex]
[tex]z = [H_2] - 4y = 0.300 - 4(2x) = 0.300 - 8x$[/tex]
Substituting these expressions into the equilibrium expression and solving for $x$:
[tex]K_c = \dfrac{(2x)(2y)^2}{x(0.300 - 8x)^4} = 3.80$[/tex]
Solving this equation gives:
[tex]x = 0.0371\ \mathrm{M}$[/tex]
Therefore, the concentration of carbon monoxide is also [tex]x = 0.0371\ \mathrm{M}$.[/tex]
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g when 15.5g of lead nitrate reacts with 15.5g of potassium iodide, 17.2g of lead iodide is produced. what is the percent yield?
The percent yield of the reaction is 79.6%.
To calculate the percent yield of the reaction, we need to first calculate the theoretical yield of lead iodide based on the given amount of lead nitrate;
1 mol Pb(NO₃)₂ = 331.2 g
15.5 g Pb(NO₃)₂ = 15.5/331.2 mol Pb(NO₃)₂ = 0.0469 mol Pb(NO₃)₂
According to the balanced chemical equation, 1 mole of Pb(NO₃)₂reacts with 2 moles of KI to produce 1 mole of PbI2. Therefore,
0.0469 mol Pb(NO₃)₂ x (1 mol PbI2/1 mol Pb(NO₃)₂) = 0.0469 mol PbI₂ (theoretical yield)
The molar mass of PbI₂ is 461.0 g/mol, so the theoretical yield of PbI₂ in grams is;
0.0469 mol PbI₂ x 461.0 g/mol = 21.6 g PbI₂
Now we can calculate the percent yield:
% yield=(actual yield/theoretical yield) x 100
The actual yield is given as 17.2 g PbI₂, so
% yield = (17.2 g/21.6 g) x 100
= 79.6%
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--The given question is incomplete, the complete question is
"When 15.5g of lead nitrate reacts with 15.5g of potassium iodide, 17.2g of lead iodide is produced. What is the percent yield? Pb(NO₃)₂(aq) + 2KI(aq) → PbI₂(s) + 2KNO₃(aq)"--
The three mixtures below (a, b, and c) were prepared from three very narrow molar mass distribution of polystyrene samples with molar masses of 10000; 30000; and 100000 g mol−1
the number-average and weight-average molar masses for each are 47273 g/mol and 78872 g/mol.
To calculate the number-average and weight-average molar masses of each mixture, we need to use the following formulas:
Number-average molar mass (Mn) = (ΣNiMi) / ΣNi
Weight-average molar mass (Mw) = (ΣWiMi) / ΣWi
where Ni and Wi are the number and weight fractions of each component i, and Mi is the molar mass of component i.
(a) For the first mixture, where equal numbers of molecules of each sample were mixed, the number and weight fractions of each component are 1/3. The number-average molar mass is:
[tex]Mn = (\frac{1}{3} *10000) + (\frac{1}{3} * 30000)+(\frac{1}{3} *100000)= 46667g/mol.[/tex]
The weight-average molar mass is:
The number-average molar mass represents the average molar mass of the polymer chains in terms of their numbers, while the weight-average molar mass takes into account the relative abundance of each molar mass in terms of their weight. In this case, since the three samples have equal number and weight fractions, the number-average and weight-average molar masses are very close.
(b) For the second mixture, where equal masses of each sample were mixed, the number and weight fractions of each component are different due to their different molar masses. The number fraction of each component can be calculated as follows:
n1 = m1/M1 = 1/3
n2 = m2/M2 = 1/3
n3 = m3/M3 = 1/3
where mi is the mass of component i and Mi is the molar mass of component i.
The weight fraction of each component can be calculated as follows:
w1 = n1M1 / (n1M1 + n2M2 + n3M3) = 0.186
w2 = n2M2 / (n1M1+ n 2M2 + n3M3) = 0.294
w3 = n3M3 / (n1M1 + n2M2 + n3M3) = 0.520
where we have used the fact that the total mass of the mixture is the sum of the masses of each component, i.e. m1 + m2 + m3 = 1.
[tex]Me= (\frac{1}{3} *10000*10000)+(\frac{1}{3} *30000*30000)+(\frac{1}{3} *100000*100000)/ (\frac{1}{3} *10000) + (\frac{1}{3} * 30000)+(\frac{1}{3} *100000)= 47273 g/mol.[/tex]
Using these fractions, we can calculate the number-average and weight-average molar masses of the mixture:
[tex]Mn = (\frac{1}{3} *10000) + (\frac{1}{3} * 30000)+(\frac{1}{3} *100000)= 46667g/mol.[/tex]
Molecular weight= [tex](0.186 x 10,000 x 10,000) + (0.294 x 30,000 x 30,000) + (0.520 x 100,000 x 100,000) / (0.186 x 10,000) + (0.294 x 30,000) + (0.520 x 100,000) = 78,872 g mol-1[/tex]
In this case, the weight-average molar mass is significantly higher than the number-average molar mass. This indicates that the higher molar mass component (100,000 g mol-1) is contributing more to the weight of the mixture, while the lower molar mass components (10,000 and 30,000 g mol-1) are contributing more to the number of polymer chains
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why is a carbonyl group polar?select the correct answer below:carbon is significantly more electronegative than oxygen.oxygen is significantly more electronegative than carbon.oxygen is significantly more electropositive than carbon.none of the above
A carbonyl group polar because b. oxygen is significantly more electronegative than carbon.
The carbonyl group is a functional group in organic chemistry consisting of a carbon atom double-bonded to an oxygen atom. C=O is the formula for a carbonyl group, this structure is present in many ketones and aldehydes, as well as carboxylic acids, esters, and amides. Oxygen is much more electronegative than carbon, and as a result, the electrons in the carbon-oxygen double bond are more strongly attracted to the oxygen atom. Because the electrons are attracted to the oxygen atom, the carbon-oxygen bond becomes polarized, with oxygen becoming negatively charged and carbon becoming positively charged.
The carbonyl group is an important functional group in biochemistry since it is found in a variety of biomolecules like carbohydrates, lipids, and nucleic acids. Because of its polarity, it can engage in hydrogen bonding with other functional groups in these molecules, such as hydroxyl groups. A carbonyl group polar because b. oxygen is significantly more electronegative than carbon.
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If a 454.4 g sample of chlorine gas (MM = 71.0 g/mol) was
reacted with excess hydrogen at 565 K and 2.30 atm, how
many grams of hydrogen chloride gas (MM = 36.5 g/mol) are
produced?
Answer:
Isabelle is taking a survey to find the most popular music group of students in her community. Which of these is not a way for her to get a representative sample of this information?
ask every tenth student she sees ac a concert
ask every fifth student entering her school in the morning
ask every third student she encounters at the mall
ask every student at a local movie theater
Explanation:
simple help pls picture down below
Answer:
Option B
Explanation:
25 a sample of a compound contains only the elements sodium, sulfur, and oxygen. it is found by analysis to contain 0.979 g na, 1.365 g s, and 1.021 g o. determine its empirical formula.
The empirical formula of the compound is Na2S.
To find the number of moles of each element in the compound, we divide the mass of each element by its atomic mass.
The atomic masses of sodium, sulfur, and oxygen are 22.99 g/mol, 32.06 g/mol, and 16.00 g/mol, respectively.
Thus, the number of moles of sodium in the compound is
0.979 g/22.99 g/mol = 0.0425 mol.
Similarly, the number of moles of sulfur and oxygen in the compound are
1.365 g/32.06 g/mol = 0.0425 mol and
1.021 g/16.00 g/mol = 0.0638 mol,
The next step is to determine the empirical formula of the compound. To do this, we need to find the simplest whole number ratio of the atoms in the compound. The simplest whole number ratio of the atoms in the compound is obtained by dividing the number of moles of each element by the smallest number of moles obtained.
In this case, the smallest number of moles obtained is 0.0425 mol, which corresponds to the number of moles of sodium and sulfur in the compound.
.
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36.512 ml of aqueous solution containing 0.111 moles of reactant a in a calorimeter at 25.0oc undergoes the following reaction: a(aq) --> b(aq). (the solution and the calorimeter are initially both at 25oc) when the reaction is complete, the temperature of the solution and the calorimeter is 46.84 oc. what is the enthalpy of the reaction in units of kj/mole of a? assume that the density of the solution is 1.000 g/ml, the specific heat of the solution is 4.186 j/goc, and the calorimeter has a heat capacity of 15.558 j/oc.
The enthalpy of the reaction is -58.7928 kJ/mol of A. Note that the negative sign indicates that the reaction is exothermic (heat is released).
To calculate the enthalpy of the reaction (ΔH) in units of kJ/mole of A, we can use the following equation; ΔH = -q/n
where q is the heat absorbed or released by the reaction, and n is the number of moles of reactant A.
First, we need to calculate the heat absorbed or released by the reaction (q). We can use the following equation to calculate q:
q = m × c × ΔT + C_cal × ΔT
where m is the mass of the solution, c is the specific heat of the solution, ΔT is the change in temperature (T_final - T_initial), and C_cal is the heat capacity of the calorimeter.
The mass of the solution can be calculated using the density of the solution;
mass = volume × density = 36.512 mL × 1.000 g/mL = 36.512 g
Substituting the given values, we get;
q = 36.512 g × 4.186 J/g°C × (46.84°C - 25.0°C) + 15.558 J/°C × (46.84°C - 25.0°C)
= 6524.1 J
Next, we need to calculate the number of moles of reactant A
n = 0.111 moles
Now we can calculate the enthalpy of the reaction:
ΔH = -q/n = -(6524.1 J)/(0.111 moles) = -58792.8 J/mol
Finally, we convert the result to kJ/mol
ΔH = -58.7928 kJ/mol
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a student failed to notice a bubble in the tip of the burette before starting a titration. how does the bubble affect the final reading of the volume of naoh at the end point of the titration? biased high or biased low? explain your answer
The bubble in the tip of the burette will lead to an inaccurate final reading of the volume of NaOH at the end point of the titration.
The reading will be biassed high as a result of the bubble. This is so that, without really contributing to the measurement, the bubble will increase the volume of NaOH in the burette.
The bubble is not a component of the measurement, thus any volume it occupies will be added to the final value, making the reading higher than it should be.
As a result, the bubble will produce an unreliable and skewed high reading, which could result in false results.
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compound has a molar mass of and the following composition: element mass % phosphorus 43.64% oxygen 56.36% write the molecular formula of .
The molecular formula is 2(P2O5), or P4O10.
To determine the molecular formula of the compound, we first need to find the empirical formula. We can assume 100 g of the compound, which means that there are 43.64 g of phosphorus and 56.36 g of oxygen.
We can convert the masses of each element to moles by dividing by their respective atomic masses:
moles of P = 43.64 g / 30.97 g/mol = 1.41 mol
moles of O = 56.36 g / 16.00 g/mol = 3.52 mol
Next, we can divide each number of moles by the smallest number to get the mole ratio:
P:O = 1.41 mol / 1.41 mol = 1
O:O = 3.52 mol / 1.41 mol = 2.49
We can round the mole ratio to the nearest whole number to get the empirical formula: P2O5
To find the molecular formula, we need to know the molar mass of the compound. Let's assume it is 284 g/mol (a multiple of the empirical formula mass of 142 g/mol).
We can divide the molar mass by the empirical formula mass to get the integer multiple:
n = 284 g/mol / 142 g/mol = 2
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How many protons, neutrons, and electrons are in this ion?
Answer:
Ans C is the correct one.
As the element with 15 proton 15 electrons and 16 neutron is phosphorus
when the pressure of helium gas is increased to 4.1 atm, the volume is reduce to 1.2 l at a final temperature of 15 degrees celsius. what was the initial temperature of helium gas with a pressure of 3.5 atm and a volume 1.5 L?
Explanation:
Re-arrange the equation to :
T1 = P1V1 * T2 / (P2V2) and note that temp needs to be in K
15C = 288.15 K
T1 = 3.5 (1.5)(288.15) /(4.1 * 1.2) = 307.48 K which is 34.3 C