2NO2(g)--> 2NO(g) + O2(g) , H=+114.2kJ

(Note: H, S, G all have a degree sign next to them)

NO: H(enthalpy)=90.3kJ/mol, S(entropy)=210.7J/mol*K, G(gibbs energy)=86.6

O2: H(enthalpy)=0, S(entropy)=?, G(gibbs energy)=0 kJ/mol

NO2: H(enthalpy)=33.2, S=239.9, G=51

For part a, I have to calcuate G for the reaction.

I used the Gibbs free standard reaction formula:where i have to find the sum of products minus the sum of reactants.
I got 71.2 kJ/mol. I know I got that right because my friend got the same answer too.

for part b, I have to calculate standard entropy, S for only O2.
There's a table in my book saying that entropy of O2 is 205 J/mol*K.
But I have to solve this using formulas and I was wondering if you can help on how to approach this problem.

1. 👍
2. 👎
3. 👁
1. The temperature of the reaction is 298 kelvin

1. 👍
2. 👎
2. This is what I did:

my teacher said that this is a two step calculation:
First step:equation of heat
q=mct
m=mass of O2=32 grams
T=298+273=573 Celsius
q=32 g of O2(4.184J/g C)(573 C)
q=76450J/mol

then I used the equation:
S(entropy)=q/T
S=76450J/mol / (298 K)
=257 J/mol*K

I looked at a table in my chemistry book, and it says that S of O2 is 205 J/mol*K.
I'm assuming that's the answer I should reach, but I didn't.

So please see what I did wrong.
Thank you

1. 👍
2. 👎
3. 298 K is not 573 C. It is 25 C

Entropy at 298 requires an integration of C dT/T from 0 K to 298, including solid and liquid phases. It cannot be calculated with a simple formula. The 205 J/mol K number for 298 K agrees with my JANNAF Tables.

1. 👍
2. 👎

## Similar Questions

1. ### Chemistry

The Keq for the equilibrium below is 5.4 × 1013 at 480.0 °C. 2NO (g) + O2 (g) ↔ 2NO2 (g) What is the value of Keq at this temperature for the following reaction? NO2 (g) ↔ NO (g) + 1/2 O2 (g) The Keq for the equilibrium

2. ### Chemistry

The equilibrium constant for the reaction 2NO(g) + O2(g) 2NO2(g) is Kp=1.48x10^4 at 184C. Calculate Kp for 2NO2(g) 2NO(g) + O2(g). I know the equation is Kp=Kc(RT)x Delta n Kp is what we're solving for Kc= I can't seem to find.

3. ### Chemistry

What is the process to calculate ΔH° for the reaction? O2(g) + 2NO(g) --> N2O4(g) O2(g) + 2NO(g) --> 2NO2(g) ΔH°1 N2O4(g) --> 2NO2(g) ΔH°2 a) ΔH°1 + ΔH°2 b) ΔH°1 - ΔH°2 c) ΔH°2 - ΔH°1 d) ΔH°1 - 2ΔH°2 I know

4. ### Chemistry

Nitric acid can be produced from NH3 in three steps process: I)4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g) II)2NO(g) + O2(g) → 2NO2(g) III)3NO2(g) + H2O(l) →2HNO3(aq) + NO(g) % yield of Ist, IInd & IIIrd are respectively 50 % , 60 %

1. ### chemistry

2NO + O2 = 2NO2 How many grams of NO2 will be produced when 5.00 moles of NO react?

2. ### physics

Suppose the amount of heat removed when 3.0kg of water freezes at 0 degree C were removed from ethyl alcohol and its freezing/melting point of -114 degree C. How many kilograms of ethyl alcohol would freeze? PLEASE GIVE ME SOME

3. ### chemistry

how do i solve the following problem? Nitrogen dioxide decomposes to nitric oxide and oxygen via the reaction: 2NO2 → 2NO + O2 In a particular experiment at 300°C, [NO2] drops from 0.0100 to 0.00650 M in 100 s. The rate of

4. ### chem class

The value of Keq for the following reaction is 0.25: SO2 (g) + NO2 (g) SO3 (g) + NO (g) The value of Keq at the same temperature for the reaction below is __________. 2SO2 (g) + 2NO2 (g) 2SO3 (g) + 2NO (g) answer is 0.25 how do i

1. ### chemistry

In the reaction O2+2NO->2NO2 what is the ratio of oxygen reacted to nitrogen dioxide produced? Nitrogen monoxide to nitrogen dioxide? We had to calculate the concentration of each, for which I have O2=-1.01x10^-5, NO=-2.03x10^-5

2. ### Chemistry

Under the appropriate conditions, NO forms NO2 and N2O: 3NO(g) N2O(g) + NO2(g) Use the values for delta G naught for the following reactions to calculate the value of Kp for the above reaction at 500.0 C 2NO(g) + O2(g) 2NO(g)

3. ### Genera Chemistry

Nitric oxide (NO) reacts with oxygen gas to form nitrogen dioxide (NO2), a dark-brown gas: 2NO(g) + O2(g) -> 2NO2(g) In one experiment 0.886 moles of NO is mixed with 0.503 moles of O2. Calculate which of the two reactants is the

4. ### Chemistry

Consider the following reaction: 2NO(g)+O2(g)→2NO2(g) Estimate ΔG∘ for this reaction at each of the following temperatures and predict whether or not the reaction will be spontaneous. (Assume that ΔH∘ and ΔS∘ do not