In Investigation One, you analyzed how chemical compounds react in a chemical reaction to produce other chemical compounds and sometimes heat. During this Investigation, you will:

1. Examine chemical reactions using the following reactants:

• ammonium hydroxide (NH4OH)
• hydrochloric acid (HCl)

2. Construct a calorimeter to measure the temperature change resulting from the chemical reactions.

3. Observe any changes that may have occurred as a result of the chemical reactions.

In Investigation Two, you will analyze how changing the amounts of the reactants in a chemical reaction affects the amount of the products that are produced. During this Investigation, you will:

1. Test the reaction of 2 ml of hydrochloric acid (HCl) with 0.5 g of magnesium.
2. Test the reaction of 15ml of hydrochloric acid (HCl) with 0.5g of magnesium.
3. Test the reaction of 50ml of hydrochloric acid (HCl) with 0.5g of magnesium.
4. Test the reaction of 75ml of hydrochloric acid (HCl) with 0.5g of magnesium.
5. Test the reaction of 100ml of hydrochloric acid (HCl) with 0.5g of magnesium.
6. Test the reaction of 100ml of hydrochloric acid (HCl) with 1 g of magnesium.
7. Calculate the volume of a sphere using the following formula:

 Volume of a sphere = 0.52 • d3 = 0.52 • (d • d • d)

In Investigation Three, you will analyze how changing the amount of one reactant in a chemical reaction affects the amount of time it takes the reaction to be completed. During this Investigation, you will:

1. Combine iodine, water, and hydrochloric acid (HCl) in designated amounts and observed the time it took for a completed reaction.
2. Calculate reaction time by converting minutes to seconds.
3. Use the spectrophotometer to measure the absorbance of each chemical sample.

This Performance Assessment is designed to allow students to solve a problem using the:

• concepts with which they have become familiar during the previous three Investigations, and
• procedures used during the previous three Investigations.