CHANGES OF STATE

Pg .

!"#*%Qtreleaxd tQabsabed=1

Q Released ( Gold) Qabsorbed (Ethyl

Akiho.

m=?

m=D=m- V= soonl ✓

Tf = 34°C m=Dvc= B.!D×B1B BF=1.#"D g/nl

kitm=

1.#"DBI×J11Im= FDI.Jgm= 1.FDkg .

Ti=!siTf= !#°Cc= !.I%×B1 't C

Released (gold) Absorbed

MCAT + MCDT =O

M€!D.no?#3ic-BCgt(o.FBkg)(3.IJxYyIz)(3io3Cc)=O(P443yIg)mtlBlP.PJ=o

- "## }÷(m)= - BDB"."J

m = -

BDB"."¥!€,

lm=O.!!§

THERMAL EXPANSION AND CONTRACTION

| Thermal Expansion:y the expansion of a substance as it warms up

| Thermal Contraction:y the contraction (shrinking) of a substance when it

cools down

HEATING CURVE FOR WATER

Ice (below 0⁰C)

Changing states (temp doesn’t change!)*all additional thermal energy is used

to melt the ice

Water remainsliquid...gets hotter

B

A

C

Changing states *all thermal energyis used to evaporate the water

D

| Q: What do the flat parts of the graph indicate?

-temperature is not changing because the added thermal energy is changing the physical state of the water

-two states of matter are present-thermal energy is used to break the bonds

connecting the particles

LATENT HEAT

| “Latent” – hiddeny Absorbed thermal energy is stored in the material

until the opposite change of state can release it

| “Latent heat of fusion” – the amount of thermal energy required to change a solid into a liquid (melts) or a liquid into a solid (freezes)

| “Latent heat of vaporization” – the amount of thermal energy required to change a liquid into a gas or a gas into a liquid.

Absorbing QLT )

Releasing Qt )

Absorbing Releasing

Absorbing

Releasing

| “Specific latent heat” – the amount of thermal energy per kilogram of a substance required for a change of state

Q=mLfQ=mLV

EXAMPLE #1| p. 293 #3

| HWK: y Read 6.4y P.295 #1-4, 6-9⇐

,F,I

,%-D

Pg !DF*F .

Steam B11°C → Water B11°C¥ water ioic → Water CT°C

m= J11g * Assume Zsig= T.C kg digs .

Lr = !.F×B1%÷g

[ = I.B"×B1F J

*

QReieasediQhvtQaiTQI@HVkgK.FxZobEDo.QreYYdsoooosZTICooJQe-l.Zso.oooJ-sot3TQ-mcyTiol.FogoooJd.sksKIlPosF.D

( sic - ioic)

Q = - B1I,

soo J