Experiment 6 Prelab Quiz

The temperature of a sample of iron increased by 23.6 °C when 257 J of heat was applied. What is the mass of the sample?

24.254 g

A calorimeter is used to measure the enthalpy of a reaction. Label the system and the surroundings.

Calorimeter + air = surroundings Contents = system

Which of the following would be the best choice for dealing with an acid spill in lab?

Notify the TA or instructor and let them deal with it.

Select the safe methods to determine if a hot plate is heating. (Select all correct responses)

Observe the heating indicator light (if available). Place the back of your hand a few inches above the surface.

In a calorimetry experiment the calorimeter heat capacity, or calorimeter constant Ccal, must be determined before finding heats of neutralization or formation. Sort the steps listed below into the correct order for calculating the heat capacity of a calorimeter

Step 1 - record Tinitial of the warm and cold water Step 2 - add warm water to cool water and record Tfinal Step 3 - calculate delta Tcool and delta Twarm Step 4 - find qcool and qwarm using q = mCdeltaT Step 5 - use qsurr = -qsys to find qcal Step 6 - find Ccal using qcal and delta Tcool

Which of the following best defines specific heat?

The amount of heat required to increase the temperature of 1 g of a substance by 1 °C.

Consider the process of accelerating a car from 0 to 60 miles per hour in 10 seconds versus 30 seconds. Select all the true statements.

The change in energy for both processes is the same.

What is the purpose of the coffee cup in a coffee cup calorimetry experiment?

The coffee cup insulates the experiment, minimizing heat loss to the environment.

Label the direction of heat flow between system and surroundings for each process.

a. Endothermic heat goes from surroundings to the system b. Exothermic heat goes from system to the surroundings

7. Which of the following statements are true? ΔH for an endothermic reaction is positive ΔH for an exothermic reaction is positive When energy is transferred as heat from the system to the surroundings, ΔH is negative. When energy is transferred as heat from the surroundings to the system, ΔH is negative. The evaporation of water is an exothermic process. A combustion reaction is exothermic.

ΔH for an endothermic reaction is positive When energy is transferred as heat from the system to the surroundings, ΔH is negative. A combustion reaction is exothermic.