You and a friend are hiking the Appalachian Trail when a storm comes through. You stop to eat, but find that all available firewood is too wet to start a fire. From your Chem 106 class, you remember that heat is given off by some chemical reactions; if you could mix two solutions together to produce an exothermic reaction, you might be able to cook the food you brought along for the hike. Luckily, being the dedicated chemist that you are, you never go anywhere without taking along a couple chemical solutions called X and Y just for times like this. The Virtual Lab contains solutions of compounds X and Y of various concentrations. These compounds react to produce a new compound, Z, according to the reaction:
The following activities will guide you in using this reaction to produce the heat needed to warm up your food.
1) First, measure the enthalpy of the reaction shown above.
2) To design the solutions you will need to heat your food, you can obtain valuable data by mixing:
a) 100 ml of 0.1 M Solution X with 100 ml of 0.1 M Solution Y
b) 50 ml of 0.1 M Solution X with 50 ml of 0.1 M Solution Y
c) 100 ml of 0.1 M Solution X with 100 ml of 0.2 M Solution Y
d) 100 ml of 0.2 M Solution X with 100 ml of 0.1 M Solution Y
e) 100 ml of 0.2 M Solution X with 100 ml of 0.2 M Solution Y
Make each of these mixtures in the Virtual Lab. Explain the temperature changes you observe in terms of the various volumes and concentrations involved.
3) Based on what you learned in step 2 of this problem, design solutions of X and Y, initially at 25°C, that when mixed together in equal volumes cause the temperature of the mixture to increase from 25°C to 70°C. Use the Virtual Lab to verify that the solutions you devised reach 70°C when mixed together. If you succeed, you'll have enough heat to warm up your food-better camping through chemistry!