Preview - Energy In Chemical Reactions

Calorimetry Lab Design Part 1: Reactant Amounts

The purpose of the lab is to measure the energy absorbed or released in a chemical reaction. You will utilize a calorimeter to measure the energy absorbed or released in the following chemical reaction:

Ca (s) + 2 H2O (l) → Ca(OH)2 (aq) + H2 (g)

In this reaction you have two reactants, calcium and water. The amount of calcium will be your independent variable. The amount of water will be a controlled variable, as you will keep it constant for all trials. Energy absorbed or released will be your dependent variable. Anything that is constant throughout your experiment is a controlled variable.

As you run your experiment, you will use three different amounts of calcium. You will run each trial three times, for a total of nine trials. The amount of water must be held constant throughout your experiment.

Questions

Please answer the questions below.

Choose three different quantities of calcium in the range below and choose a set amount of water in the range below.

  • Range for amounts of calcium: 0.10 – 0.50 grams
  • Range for amount of water: 80.0 – 120.0 mL

Calorimetry calculations will require that the quantity of water used be expressed as a mass rather than a volume. Your volume of water can be converted to a mass expressed in grams using the the density of water which is 1 g/mL. For example, if your volume of water is 50mL, that is equal to 50 g as 50g/50mL = 1 g/mL. Convert your volume of water to a mass in grams.

Calorimetry calculations will also require the total mass of solution. Your solution is comprised of your solute (calcium) and your solvent (water). Thus, in order to calculate the mass of solution for each experiment you will add your mass of calcium to your mass of water for each experiment.

Notes

These notes will appear on every page in this lesson so feel free to put anything here you'd like to keep track of.