Table I/Heat Quick Review

When a reaction from Table I is flipped (reversed) what happens to the heat of reaction (ΔH)?

• it doubles

• it halves

• its sign changes

• it triples

According to Table I which of the following salts dissolves exothermically in water?

• KNO₃

• NH₄Cl

• NaCl

• LiBr

According to Table I when 4 moles of NO(g) are formed...

• 182.6 kJ of energy are absorbed

• 182.6 kJ of energy are released

• 365.2 kJ of energy are absorbed

• 365.2 kJ of energy are released

Temperature is defined as...

• A measure of average potential energy

• A measure of average of kinetic energy

• A measure of heat energy

• Degrees Celsius

Which of the following samples of matter has the lowest average kinetic energy?

• 100 g of water at 50 °C

• 50 g of water at 25 °C

• 10 g of copper at 80 °C

• 500 g of copper at 10 °C

What will be the direction of heat flow when a 50 g block of aluminum at 85 °C is place in 500 mL of water at 20 °C?

• from the water to the aluminum

• left

• up

• from the aluminum to the water

Which of the following processes is endothermic?

• H₂O(s) → H₂O(l)

• H₂O(g) → H₂O(l)

• H₂O(g) → H₂O(s)

• H₂O(l) → H₂O(s)

A student conducts a lab exercise in which the reaction being observed experiences a decrease in temperature. What can be concluded from this observation?

• the reaction is endothermic

• the reaction is exothermic

• there is an increase in average kinetic energy

• there is a phase change occurring

According to Table I which substance is formed in a highly exothermic reaction?

• C₂H₆

• HI

• Al₂O₃

• NH₃

A positive sign on the ΔH found in Table I means the reaction is...

• endothermic

• exothermic

• hot

• cold