Thermodynamics Part B Quiz

If water is heated on the stove (assuming it does not boil), what will happen to the molecules?

molecules will move faster

enthalpy

stored heat

Which of the following situations is endothermic?

Photosynthesis

What happens to the temperature of a substance during a phase change?

It stays the same

Water is boiling and you turn down the heat. What happens to the temperature, assuming the water keeps boiling?

temperature stays the same

At which letter(s) is there a phase change?

B, D

What is specific heat?

the amount of energy required to increase 1g of a substance by 1^oC

Which substance has the highest specific heat?

Water

What will immediately happen to 100^oC steam if it is placed at room temperature?

the steam will condense

What will happen immediately is 25^oC water is placed in the freezer?

the temperature will drop, molecules move slower

What will happen immediately to -10^oC ice is placed on the counter?

the ice will heat up and molecules will move faster

What phase changes are exothermic?

Freezing, condensation, deposition

What phase changes are endothermic?

Melting, evaporation, sublimation

Assuming there is no change of state, what happens to the molecules in a substance when energy is removed? What will this do to the temperature?

They slow down, causing the temperature to drop

thermodynamics

heat change

if 100*C water is placed at room temperature

Molecules slow down, which causes the temperature to drop

If energy is added to 100*C water it will…

evaporate

if 0*C water is placed in the freezer

It will start to freeze

What equation do you use when melting or freezing a substance

q= Hf X M

What equation do you use when condesation or boiling a substance

q= Hv • m

What equation do you use when heating or cooling a substance

q= C x M x Δt