Name:__________________________

Virtual Lab Part 2: Design a Hot/Cold Pack

[Cold Pack]. Based on your results from part 1, design a cold pack using NH₄NO₃(s). It should have a total mass of g (salt plus water) and be able to achieve a temperature of °C. Assume a specific heat for the solution of 4.184 J/g°K (same as for water) and an initial temperature of 25°C for the water in the cold pack.

You can check your calculations in the virtual lab below. To create a calorimeter in the virtual lab, right click on any piece of glassware and choose "Thermal Properties.." In the Thermal Properties dialogue box, check "insulate". Assume that the calorimeter container does not absorb any heat and that the specific heat for the solution is 4.184 J/gºK (same as for water). You may also find the scale useful in your experiment.

To ensure that the amount of solid added to the calorimeter is accurately recorded, the mass of salt should be weighed out by differences. Click on "Solid" button on the "Solution Information" window on the right. Highlight the jar of salt to see the mass of the solid. Transfer the required amount to the calorimeter and check the mass of the salt again.

[Hot Pack]. Based on your results from part 1, design a hot pack using MgSO₄(s). The hot pack should have a total mass of g (salt plus water) and be able to achieve a temperature of °C. Assume a specific heat for the solution of 4.184 J/g°K (same as for water) and an initial temperature of 25°C for the water in the hot pack.

You can check your calculations in the virtual lab below. To create a calorimeter in the virtual lab, right click on any piece of glassware and choose "Thermal Properties.." In the Thermal Properties dialogue box, check "insulate". Assume that the calorimeter container does not absorb any heat and that the specific heat for the solution is 4.184 J/gºK (same as for water). You may also find the scale useful in your experiment.

To ensure that the amount of solid added to the calorimeter is accurately recorded, the mass of salt should be weighed out by differences. Click on "Solid" button on the "Solution Information" window on the right. Highlight the jar of salt to see the mass of the solid. Transfer the required amount to the calorimeter and check the mass of the salt again.

Note: A newer version of this activity with working autograding is available here.

Design a Hot/Cold Pack: DONE

You can now print this page to turn in with your prelab.