GENERAL CHEMISTRY (1st mastery) #2

evaporation

When ironing clothes, the water sprayed on the fabric disappears. What phase change occurred?

melting

Icicles melt during the daytime under the sun. What phase change is involved?

sublimation

When dry ice is used during a stage performance, it produces fog without forming a liquid. What phase change is that?

condensation

Fog forming in the early morning as the air cools down is due to what phase change?

melting

When candles are lit, the solid wax becomes liquid. What phase change is this?

deposition

Snow forming from water vapor in the atmosphere without becoming liquid is an example of what phase change?

condensation

After opening a soda bottle from the fridge, droplets form on its outer surface. What phase change occurred?

freezing

When you put hot soup in the fridge and it turns into a solid, what phase change occurred?

melting

When you heat butter in a pan and it turns into liquid, what phase change is this?

evaporization

At a fiesta, someone spilled cold soft drink on the table. Minutes later, it disappeared without being wiped. What phase change occured?

nature of the substance, temperature, pressure

phase changes depends on the:

phase diagram

Graphical representation of pressure-temperature relationship. Convenient way to represent graphically the conditions at which a particular state is stable.

heating curve

heat is added

Endothermic – absorbs heat

Flat Line = Phase Change

cooling curve

heart is removed

exothermic - gives off heat

flat line = phase change

triple points

which all three phases co exist

critical point

critical pressure and temperature

supercritical fluid

beyond critical point where there is no boundaries between gas and liquid and can no longer be liquefied

triple point, critical point, supercritical fluid

key terms in phase diagram:

phase change

what do you call the change from one state to another?

kinetic energy

what energy is associated with an object’s motion?

it stays the same

When an object undergoes phase changes, what happens to its temperature?

sublimation

What do you call the transition from a solid to a gas?

melting

What do you call the transition from a solid to a liquid?