Sodium carbonate (Na2CO3) reacts with acetic acid (CH3COOH) to form sodium acetate (NaCH3COO), carbon dioxide (CO2), and water (H2O). A chemist carries out this reaction in a bomb calorimeter. The reaction causes the temperature of a bomb calorimeter to decrease by 0.985 K. The calorimeter has a mass of 1.500 kg and a specific heat of 2.52 J/g•K. What is the heat of reaction for this system?
Answers
Given:
Mass of bomb calorimeter, m = 1.5 kg = 1500 g
Temperature change of calorimeter, ΔT = - 0.985 K
Specific heat of calorimeter, c = 2.52 J/g K
To Find:
The heat of reaction for this system
Calculation:
The heat of reaction can be calculated by the given formula:
Q = mcΔT
⇒ Q = 1500 × 2.52 × (- 0.985)
⇒ Q = - 3723.3 J (-ve sign shows heat is given by calorimeter)
- So the heat of reaction is -3723.3 J or -3.7233 kJ
Given: The calorimeter has a mass of 1.500 kg and a specific heat of 2.52 J/g•K
To find: heat of reaction for this system.
Solution:
- As we are able to see that we are working in a calorimeter, its associated heat is equal to the enthalpy of reaction as due to the change in its mass and in the temperature.
- In such a way, we compute it as follows:
Formula is:
Δ(r) H = m x C(p) x ΔT
Δ(r) H = 1.5 kg x 2.52 J/(g x k) x (-0.985K)
Now, converting 1.5 kg to gram, we get:
Δ(r) H = 1.5 kg x 1000g/1.5 kg x 2.52 J/(g x k) x (-0.985K)
After all the calculations, we get:
Δ(r) H = -3723.3 J.
- As we can see that the final answer is in negative term, it is because the temperature in the calorimeter is decreased.
Answer:
Heat of reaction for this system is -3723.3 J.