1. 200 G of an Unknown Metal Is Heated to a Temperature of 2000 C, Then Dropped Into 50

Exploration1 : Calorimetry

1. 200 g of an unknown metal is heated to a temperature of 2000 C, then dropped into 50 g of water at 200 C in an insulated container. The water temperature rises to 39.70 C and then stops rising.

a. Find the specific heat capacity of the metal.
b. Based on information from Table 12.2 or some other source, identify the metal.

2. Materials A and B have equal densities, but A has a larger specific heat than B. You have 100 g cubes of each material.

a. Cube A initially at 00C, is placed in good thermal contact with cube B, initially at 2000C. The cubes are inside a well-insulated container, where they don’t interact with their surroundings. Is their final temperature greater than, less than, or equal to 1000C? Explain.

b. Cube A and B are both heated to 2000C, then placed on a table in room-temperature air. Which one cools down more quickly? Explain.

3. A 200 g piece of iron at 1200C and a 150 g piece of copper at -500 C (minus 50 degrees) are dropped into an insulated beaker containing 300 g of ethyl alcohol at 200 C. What is the final temperature?

4-5 Answer the following ranking tasks involving the concept of specific heat:

Ranking Task 1: Heat and Temperature I

Shown below are insulated identical containers. Each container holds different amounts of the same fluid at the same initial temperature. The amount of fluid is represented by the height of the fluid in the container. Equal amounts of energy are transferred to each container.

Rank these diagrams from least to greatest final temperature of the fluid. If any figures represent the same temperature, rank them the same; ties are possible.

Least 1______2______3______4______5______6______Greatest

Explain the reasoning for your ranking. ______

Ranking Task 2: Heat and Temperature II

Shown below are insulated identical containers. Each container holds a different fluid at the same initial temperature of 00 C. Assume the mass of each fluid is the same. Energy was provided to each container to raise the temperature to the values shown. Rank these diagrams from least to greatest quantity of energy provided to each container. If any figures represent the same energy transferred, rank them the same; ties are possible.

A. BenzeneB. Ethyl Alcohol C. WaterD. Mercury

E. WaterF. Glycerin

Least 1______2______3______4______5______6______Greatest

Explain the reasoning for your ranking. ______

Prelab for Calorimetry Lab

You have 100 grams of water in an aluminum cup that has a mass of 25 grams. Both water and aluminum have come to thermal equilibrium at room temperature (220 C).

1. What will be the calculated final temperature of the mixture if 10 grams of 00 C water is added?

2. What will be the final temperature of the mixture if 10 g of 0° ice are added?

3. What are the two “mystery metals” and what is the specific heat capacity of each?

Calorimetry– Calorimetry Lab

Equipment: Computer, with Logger Pro software, temperature probe, calorimetry apparatus, ice, ice water, mystery metal, heated to 100, beaker for water pipette, paper towels.

Part 1: Phase Change

Objective: In this lab, you will use a calorimeter, as described in section 12.7 of your text, to observe the effect of phase changes on temperature change in an isolated system. The systems are the following:

Water, initially at room temperature
The aluminum cup of the calorimeter
Ice water at 00 C
Ice at 00 C

Procedure:

1. Obtain the mass of the aluminum cup and record ______kg

2. Zero the balance with the aluminum cups on it (it should read zero with the cup on it).

3. Measure 100g room-temperature water and record initial temperature: ______0C

4. Assemble the calorimeters and add the 100 g water.

5. As quickly as possible, measure 10 g of 00 ice-water, add to calorimeter and stir until temperature reaches equilibrium once again..

6. Repeat for the 10 g of ice. Keep stirring with the temperature probe.

Final MeasuredTemperature of water with ice water added:______

Final Calculated Temperature of water with ice water______

Percent Difference (should be within 10%): ______-

Final Measured Temperature of water with ice added:______

Final Calculated Temperature of water with ice added______

Percent Difference (should be within 10%): ______-

If there is a difference in the final water temperature in the two cases (ice water and ice), explain why:

Part 2 –Mystery Metal

Objective: In this lab, you will use a calorimeter, as described in section 12.7 of your text, to measure the temperature change of three interacting systems, which are in contact with each other, but isolated from the rest of the environment. The systems are the following:

Water, initially at room temperature
The aluminum cup of the calorimeter
2 plugs of mystery metal, either Zinc (Zn) or Tin (Sn)

NOTE: There should be an even number of groups, with half of the groups getting one of the mystery metals and the other half getting the other. Each group should identify a “partner group” with the other mystery metal, for later comparisons.

Procedure:

1. Obtain the mass of the aluminum cup you will be using and record.

2. Zero the balance with the aluminum cup on it (it should read zero with the cup on it).

3. Measure 130g room-temperature water.

4. Assemble the calorimeter and start to record the temperatures.

5. Extract the appropriate metal plugs (2) from the hot-water bath with the tweezers and insert into the small top “port” of the calorimeter. Make sure the cap is replaced.

6. Wait for equilibrium (temperature stops changing).

7. Dry off the mystery metal and obtain its mass.

7. Get with a group that had the other “mystery metal”.

8. Show your calculations for the specific heat capacity below and decide which group had the tin and which group had the zinc

Data for water

Mwater / T0 / Tf / cw

Data for aluminum cup 1

Malum / T0 / Tf / cal

Data for (metal)

M1 / T0 / Tf

Compare your final temperature with that of you “partner group”(check with other groups if necessary). Which metal do you think you have and why?

Final Temp______Calculated value for “c”:______

Metal Name______

Exploration2 : Phase Changes

1.A metal worker in a foundry needs to melt aluminum so that it can be used in a casting process. The aluminum (3.5 kg) is at room temperature (20 oC). How much energy, in Joules, is needed to melt the aluminum? Lf aluminum = 38.7 x 104 J/kg, melting temperature = 6600 C.

2.How much heat, in Joules, is required to raise the temperature of a cup (250 g) of water from 20 oC to 100 oC, and then to boil it away? Is heat added or released?

3.Ten grams of ammonia gas condense to form liquid ammonia. Calculate the heat involved in this phase change. Must the energy be added to or released from the ammonia? You may assume that the ammonia was initially at its condensation temperature.

4.Ice at 0 oC is placed in an isolated container that contains 1,000 g of water at 24 oC. What is the minimum amount of ice at 0 oC needed to bring the water temperature down to 0 oC?

5.In the process of making lead shot, molten lead is dripped into water. The lead forms small drops that harden to form the shot. The specific heat of the shot can be approximated as the same for both the solid and molten lead. If 0.2 kg of molten lead at 400 oC is dropped into 2 kg of water at 20 oC, what is the final temperature?

6. Your 500-mL soda is at 200 C, so you add 100 g of ice which has a temperature of -200 C. All the ice melts. What is the final temperature? Assume a well-insulated cup of soda and that ρsoda = ρwater and csoda = cwater. Do not assume that cwater = cice.