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Calorimetry Intro Lab

By Michelle Penoyer
Last updated over 1 year ago
8 Questions
Some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions.
In an exothermic process, chemical energy from a reaction is transformed into heat energy, which is released from that system. Therefore, the temperature increases. The energy required to break chemical bonds is less than the energy generated when new chemical bonds are formed, resulting in a release of heat energy.
In an endothermic process, heat energy is transformed into chemical energy so that the reaction may proceed, and thus heat is absorbed by the system. Therefore, the temperature decreases. The energy required to break chemical bonds is greater than the energy generated by the formation of new chemical bonds, and heat energy is absorbed.

In this experiment, you will examine a process and determine if it is endothermic or exothermic. You will then make predictions based on the data and evidence from the lab and practice writing compound names and formulas.
Procedure:

1. In a graduated cylinder, measure exactly 50.0 mL of water.
2. Measure the mass of the empty coffee cup calorimeter (styrofoam cups). Record this value.
3. Pour the 50.0 mL into a coffee cup calorimeter that is supported by a 250-mL beaker. Measure the mass of the coffee cup calorimeter plus water. Record.
4. Record the temperature of the water in the calorimeter. Make sure to record the temperature exactly as displayed on the screen using LoggerPro. Be careful to hold the thermometer as it can easily tip over the calorimeter.
5. Use a weigh boat to mass 2.00 g of Calcium chloride on the balance and record the exact mass in the data table.
6. Add the Calcium chloride to the water in the calorimeter. Quickly put the lid on and record the highest temperature you observe while gently swirling the calorimeter, being careful to keep the lid on.
7. When the process is complete, rinse the solution down the drain. Rinse the coffee cup calorimeter at the end of the lab. Do NOT dispose of the styrofoam cup. Flip the coffee cup and lid upside down on the lab table to dry.
Required

Record your data in the table provided:

Required

1. Calculate the amount of heat energy, q, absorbed or released in this process using the following equation:

q = heat energy (in Joules), m = mass of solution in the calorimeter (water + calcium chloride, in grams), C = specific heat of water (4.184 J/g℃), and (delta)T = temperature change (℃).
Show your work.

Required

When you dissolved calcium chloride in water, was the process endothermic or exothermic? How do you know?

Required

Would you expect dissolving Magnesium chloride in water to endothermic or exothermic? Explain your answer using the periodic table.

Required

What effect, if any, would increasing the mass of calcium chloride have on the temperature change and calculated heat energy (q)? Be specific.

Required

Describe at least two ways to distinguish an ionic compound from a molecular covalent compound.

Required

In this lab, you observed a process that was either endothermic or exothermic. Propose a different process or chemical reaction that would be the OPPOSITE type of process from the one you observed.
Why do you think this proposed process or reaction would result in the opposite changes in temperature and energy?

Required

Complete the table below. The first row is completed as an example.