Thermochemistry

Question 1

What is an endothermic reaction?

Answer 1

• Absorb energy and cause temperature drop can be measured in the surroundings
• Denoted as a positive heat flow
• Positive H (ethaply)

Question 2

What is an exothermic reaction

Answer 2

• Release heat as energy
• Denoted as negative heat flow, because it is lost to the surroundings
• Positive enthaply

Question 3

What are the two types of heat exchange that occur in a reaction?

Answer 3

1. Heat released to the products
   - Exothermic
2. Heat consumed by the reactants
   - Endothermic

Question 4

What is the law of conservation of energy?

Answer 4

-Heat is transferred not destroyed

Question 5

What is the system?

Answer 5

• Molecules involved in the reaction

Question 6

What is the surrounding?

Answer 6

-Anything else not involved in the reaction

Question 7

What is the 1st Law of Thermodynamics?

Answer 7

-Energy of the universe is constant, can only be transferred

Question 8

What is internal energy?

Answer 8

• Energy of the system

- Measured in Delta E

Question 9

What is a state function?

Answer 9

-Path doesn’t matter just where it ends up

Question 10

What is the heat capacity?

Answer 10

-Is the amount of heat required to change the temp. of a system by 1 C

Question 11

What is the specific heat capacity?

Answer 11

-Amount of heat required to change the temp. of 1 gram system by 1 C

Question 12

How does thermal energy transfer?

Answer 12

q (Heat of the system) = (-) q (surroundings)

Question 13

What is Enthalpy?

Answer 13

• Sum of the internal energy and work