# chemistry

In which one of the following processes is ΔH = ΔE?

a. 2HI(g) → H2(g) + I2(g) at atmospheric pressure.

b. Two moles of ammonia gas are cooled from 325°C to 300°C at 1.2 atm.

c. H2O(l) → H2O(g) at 100°C at atmospheric pressure.

d. CaCO3(s) → CaO(s) + CO2(g) at 800°C at atmospheric pressure.

e. CO2(s) → CO2(g) at atmospheric pressure.

1. 👍 0
2. 👎 0
3. 👁 1,563
1. Delta E = delta H -p*delta V
where work is p*delta v.
So if delta v is zero, then there is no work and delta E = delta H = qp
Note that when a reaction is at constant P, then a change in moles will result in a change in volume.
For a)
H2 + I2 ==>2HI
The work is zero because p*delta V is zero (because there are two moles of gas on the left and two moles of gas on the right). No change in moles, no change in volume and delta v is zero.

1. 👍 0
2. 👎 0

## Similar Questions

1. ### chem12

for the equilibrium 2HI(g)--- H2(g) + I2 k eq = 8.0 2.0 mol of HI are placed in a 4.0 L container, and the system is allowed to reach equilibrium. Calculate the equilibrium concentration of all three gases. Inital 2HI 0.5mol/l H2

asked by George on March 8, 2016
2. ### chem 12

for the equilibrium 2HI(g)--- H2(g) + I2 k eq = 8.0 2.0 mol of HI are placed in a 4.0 L container, and the system is allowed to reach equilibrium. Calculate the equilibrium concentration of all three gases. Inital 2HI 0.5mol/l H2

asked by George on March 10, 2016
3. ### chem12

2HI(g)--H2(g) + I2(g) k eq= 8.0 2.0 mol of HI are placed in a 4.0L container, and the system is allowed to reach equilibrium. Calculate the equilibrium concentration of all three gases Initial 2HI=0.5 mol/L H2= 0 I2=0 change 2HI=

asked by George on March 14, 2016
4. ### chem12

2HI(g)--H2(g) + I2(g) k eq= 8.0 2.0 mol of HI are placed in a 4.0L container, and the system is allowed to reach equilibrium. Calculate the equilibrium concentration of all three gases Initial 2HI=0.5 mol/L H2= 0 I2=0 change 2HI=

asked by George on March 13, 2016
5. ### science

Most of the processes that influence the hydrologic cycle are: A. biological processes. B. physical processes. C. ecosystem processes. D. wind processes. is it B

asked by Amy on July 27, 2013
6. ### Chemistry

2HI(g)--> H2(g) + I2(g) The rate law for the decomposition of HI is r=k[HI]^2. The rate of the rxn was found experimentally to b 2.5 x 10^4 mol/L x s where the HI concentration was 0.0558 M. Are these values ready to plug in to

asked by Jamie on May 16, 2010
7. ### Chemistry check my answer?

Hi! is my answer correct? Consider the following chemical reaction: H2 (g) + I2 (g) 2HI (g) At equilibrium in a particular experiment, the concentrations of H2, I2, and HI were 0.15 M, 0.033 M, and 0.55 M, respectively. The value

asked by Richard on October 25, 2010
8. ### Idontgetit

The value of the equilibrium constant (Kp) as represented by the first chemical equation is 2.00 x 10-2 at 730 K. Calculate the value of the equilibrium constant (Kp) for the second equation at the same temperature. Express answer

asked by Chemistry on October 2, 2013
9. ### Psychology

Sally is driving her car and talking on her cell phone. Statistically this behavior has been shown to be quite dangerous and contributes to many automobile accidents. In performing these two tasks simultaneously, Sally uses: a.

asked by Tessy on February 21, 2012
10. ### PSY help

Sally is driving her car and talking on her cell phone. Statistically this behavior has been shown to be quite dangerous and contributes to many automobile accidents. In performing these two tasks simultaneously, Sally uses: a.

asked by Tubbz on February 20, 2012

More Similar Questions