1) 200 grams of water are in a 60 gram aluminum cup (part of a well insulated calorimeter). A thermometer of negligible mass is immersed in the water and has read 22 °C for the last 20 minutes. A 50 gram copper cylinder that has been in a freezer (interior temperature of -8°C) all night is quickly removed from the freezer and dropped into the water. Assuming that the system consisting of the water, the cup and the cylinder is closed to energy flows:
a) What does the thermometer read after the cylinder has been in the water for a long time1?
b) If the cup (still containing the water and the copper cylinder) is removed from the calorimeter and allowed to warm to the room temperature (also 22°C) how much energy flows into the system?
2) 100 grams of ice are at 0°C.
a) How much energy must the ice absorb if it is to completely melt? If the ice were mixed with 360 grams of water initially at 30°C and the system is assumed to be closed, would the water be able to lose enough energy to melt all the ice? Show calculations and explain your reasoning.
b) If instead the ice were mixed with only 100 grams of water, would all the ice melt? Show calculations and explain your reasoning. What will be the equilibrium temperature of system? Explain how you know.
c) Consider the system and conditions described in part a. and assume a closed system. Setup an equation of the form (like in class) ΔEsys = 0 where you fill in the details including the latent heat term (see examples from class!). And use this equation to solve for the equilibrium temperature of the system. Remember the ice melts, the water cools to the equilibrium temperature and the melted ice warms to the equilibrium temperature as liquid water. There's a term for each in the equation and the equilibrium temperature is an unknown.
3) 2 grams of 100°C steam are injected into a well sealed styrofoam2 container that holds a mixture of 24 grams of ice and 50 grams of liquid water, both at 0°C. Assume that in both cases below all the steam condenses.
a) How much of the ice melts and what will be the equilibrium temperature of the mixture including the condensed steam? (Note: you need to determine if there is enough energy available to melt all the ice. The water that is now ice will not change temperature until all of it is melted.)
b) Repeat for a second experiment3 where, everything else is the same but 5 grams of steam are injected (also at 100°C).