8. Thermochemistry

Thermal Equilibrium

Multiple Choice
A 10.69-g block of solid platinum at 66.41°C is immersed in a 23.93-g pool of liquid ethanol with a temperature of 12.95°C. When thermal equilibrium is reached, what is the final temperature of the platinum and ethanol? Specific heat capacities: platinum = 0.133 J/g°C, ethanol = 2.44 J/g°C.
Multiple Choice
If 53.2 g Al at 120.0 ºC is placed in 110.0 g H2O at 90 ºC within an insulated container that absorbs a negligible amount of heat, what is the final temperature of the aluminum? The specific heat capacities of water and aluminum are 4.184 J/g ∙ ºC and 0.897 J/g ∙ ºC, respectively.
Open Question
Suppose a 50.0 g block of silver (specific heat = 0.2350 J/g∙°C) at 100°C is placed in contact with a 50.0 g block of iron (specific heat = 0.4494 J/g∙°C) at 0°C, and the two blocks are insulated from the rest of the universe. the final temperature of the two blocks
Multiple Choice
A 14.4 g sample of granite initially at 75.0 °C is immersed into 30.0 g of water initially at 21.0 °C. Assuming the specific heat capacity of granite is 0.79 J/g°C, what is the final temperature of both substances when they reach thermal equilibrium?
Multiple Choice
A 140.0 g sample of water at 20.0 °C is mixed with 100.0 g of a certain metal at 95.0 °C. After thermal equilibrium is established, the temperature of the mixture is 24.6 °C. What is the specific heat capacity of the metal?
Multiple Choice
A 140.0 g sample of water at 20.0 °C is mixed with 100.0 g of a certain metal at 95.0 °C. After thermal equilibrium is established, the temperature of the mixture is 24.6 °C. What is the specific heat capacity of the metal?
Multiple Choice
A 2.10 g sample of lead, initially at 51.0 °C, is submerged into 76.1 g of water at 17.8 °C in an insulated container. What is the final temperature of both substances at thermal equilibrium? (The specific heat capacity of lead is 0.128 J/g°C and the specific heat capacity of water is 4.18 J/g°C.)
Multiple Choice
A 2.32 g lead weight, initially at 10.1 °C, is submerged in 7.61 g of water at 53.0 °C in an insulated container. What is the final temperature of both the weight and the water at thermal equilibrium?
Multiple Choice
A 2.54 g lead weight, initially at 10.3 °C, is submerged in 7.47 g of water at 52.5 °C in an insulated container. What is the final temperature of both substances at thermal equilibrium? Express the temperature in degrees Celsius.
Multiple Choice
A 32.8 g iron rod, initially at 22.8 °C, is submerged into an unknown mass of water at 64.0 °C, in an insulated container. The final temperature of the mixture upon reaching thermal equilibrium is 59.5 °C. What is the mass of water?
Multiple Choice
A calorimeter contains 365 g of water at 30.0 °C. A 29.3-g sample of ice (at -11.0 °C) is added to the water in the calorimeter, and eventually all of the ice melts. Calculate the final temperature of the water. Assume no heat is lost to the calorimeter.
Multiple Choice
A 1.3 g wafer of pure gold initially at 69.8 °C is submerged into 64.1 g of water at 26.9 °C in an insulated container. The specific heat capacity for gold is 0.128 J/g°C and the specific heat capacity for water is 4.18 J/g°C. What is the final temperature of the system when thermal equilibrium is reached?
Multiple Choice
A piece of iron (mass = 25.0 g) at 398 K is placed in a styrofoam coffee cup containing 25.0 mL of water at 298 K. Assuming that no heat is lost to the cup or the surroundings, what will the final temperature of the water be? The specific heat capacity of iron is 0.449 J/g·K and the specific heat capacity of water is 4.18 J/g·K.
Multiple Choice
A sheet of gold weighing 10.0 g and at a temperature of 18.0°C is placed on a sheet of iron weighing 20.0 g and at a temperature of 55.6°C. What is the final temperature of the combined metals? The specific heats of iron and gold are, respectively, 0.444 J/g°C and 0.129 J/g°C.
Multiple Choice
An 80.0 g sample of metal, initially at 96.0 °C, is placed into 150.0 g of water initially at 26.0 °C in a calorimeter. The final temperature of the water is 28.1 °C. What is the identity of the metal? (The specific heat of water is 4.18 J/g°C.)