Thermochemistry Session 1

What is the freezing point of water?

• 0 degrees Celsius

• -100 degrees Celsius

• 100 degrees Celsius

• 50 degrees Celsius

What is the boiling point of water?

• 0 degrees Celsius

• 250 degrees Celsius

• 100 degrees Celsius

• 50 degrees Celsius

The first law of thermodynamics state "total energy of the universe remains __________"

What is the definition of a system in chemistry?

• All the above

• A set of things working together

• Everything that is not directly involved in the reaction

• Set of substances and energy that is being studied (chemical reaction)

What is the definition of surroundings in chemistry?

• None of the above

• Everything that is not directly involved in the reaction

• The chemical reaction

When a system is exothermic, this means heat is being _________

When the system is endothermic, this means heat is being _______ by the system

What is the equation for internal energy and what does each variable represent?

Answer explanation

E = q + w

E= internal energy

q= heat

w = work

What is the difference between heat and temperature?

Answer explanation

Heat is the EXCHANGE of thermal energy between a system and surroundings. Temperature is the MEASURE of the thermal energy within a sample of matter.

Which one of the following is an endothermic process?

• A) ice melting

• B) water freezing

• C) boiling soup

• D) Both A and C

Answer explanation

A) melting is an endothermic process because the system is absorbing heat from its surroundings to become warmer

B) Freezing is an exothermic process because the system is releasing heat to its surroundings so the system becomes cooler

C) Boiling is an endothermic process because the system is absorbing heat from its surroundings to become warmer