Lab Activity

Heat Exchange

Lab Activity: Heat Exchange

• Purpose: – (a) to investigate heat exchange when mixing liquids of

different temperatures and verify the formula: -Qloss = Qgain, or -mcΔT(hot) =mcΔT(cold).

– (b) to determine the specific heat capacity of an unknown metal, and to use that information to identify the metal.

• Materials:– Styrofoam cups, Graduated cylinder, Thermometer, hot

water (from a water bath), cold water (from tap).

Never leave a thermometer unattended!

Procedure (part 1-4)

• Place a measured amount of cold water in a Styrofoam cup (measure to 1/10 mL).

• Place a measured amount of hot water into water a Styrofoam cup.

• Take the temperature of both cups (to 1/10 °C).• Pour the cold water into the hot water.• Stir and take the temperature of the mixture.• Repeat this with four different volume combinations

(see suggested volumes)

Rewrite these instructions in procedure format

Procedure (part 5)

• Put about 50 ml (measure an exact amount) of cold water into a Styrofoam cup and measure its temperature.

• Take a piece of metal out of boiling water and add it to the cold water (boiling water should be 100°C, but use a thermometer to be sure).

• Use the beaker tag to find the mass of metal.• Find the temperature of the water after the metal

has been added.

Sample Beaker Tagfound at the corner stations for step 5

Metal #5Mass = 23.58g ± 0.03gH2O use ≈ 60mLNote: use both pieces!

Suggested amount of water to use

Mass of metalMetal #

Other instructions

Suggested volumes(do not try to get these exactly. Come close but don’t pour back and forth. Measure

to 3 significant digits)

Run Mass*water

(cold)Temp (cold)

Mass* (hot)

Temp (hot)

Final Temp

1 ≈100 g ≈ 8 °C ≈100 g ≈ 55 °C ? °C

2 ≈ 50 g °C ≈100 g °C ? °C

3 ≈100 g ≈ 8 °C ≈50 g ≈ 55 °C ? °C

4 ≈100 g °C ≈75 g ° C

5 50-70 g(see beaker tag for suggestion)

≈ 8 °C metal g(see beaker tag for

mass of metal)

≈100 °C ? °C

*for water, mass in grams = volume in mL

If time allows

Specific heat capacities of common metals.

Aluminum 0.91 Magnesium 1.05

Antimony 0.21** Mercury 0.14*

Copper 0.39 Nickel 0.59

Gold 0.13* Platinum 0.13*

Iron 0.46 Tin 0.21**

Lead 0.13* Zinc 0.39

*Gold, lead, platinum and mercury have similar specific heats, but are easy to tell apart by other properties** Antimony and Tin are similar, but we don’t use antimony.