Chemical Reactions

​John and Katrina have 2 substances:  one solid and one liquid.  John and Katrina carry out an investigation to determine if a chemical reaction occurs when the solid combines with the liquid. They determine the mass, volume, density, solubility and boiling point of the substances.  They then combine the two substances.  When the solid combined with the liquid, it bubbled vigorously and the test tube became warm to the touch.

Multiple Choice

1. Which of the following statements best describes how a chemical reaction occurs?

• New atoms are formed when substances are mixed together

• The tightly packed atoms begin to move faster and spread further apart

• Atoms of the reactants rearrange to form a new substance

• Atoms from the reactants disappear and new atoms appear

Multiple Select

2. Identify 2 questions John and Katrina could ask to help them determine if a chemical reaction occurred?

• Do the substances after combining have different masses than the substances before combining?

• Did bubbles form in the test tube after substances were combined to indicate a gas was formed?

• Do the substances after combining have different volumes than the substances before combining?

• Do the substances after combining have different properties than the substances before combining?

Multiple Choice

3. Density is the amount of mass in a given amount of volume. Using the data table above, what would be the density of substance 1?

• 10.2 g/ml because you would divide the mass of substance 1 by the volume of substance 2.

• 1.2 g/ml because you would divide the mass of substance 1 with the volume of substance 2.

• 5.33 g/ml because you would divide the mass of substance 1 with the volume of substance 1.

• 7.140 g/ml because you would divide the mass of substance 1 with the volume of substance 1.

Multiple Select

4. After analyzing and interpreting the data table above, what 2 patterns can John and Katrina identify about the substances before and after combining?

• The substances before combining have all the same properties as the substances after combining.

• The combined mass of the substances before combining are the same as the combined mass of the substances after combining.

• Substance 1 before combining has the same solubility as substance 3 after combining and substance 2 before combining has the same solubility as substance 4 after combining.

• The combined mass of the substances before combining are different from the combined mass of the substances after combining.

Multiple Choice

5. How could John and Katrina revise their investigation plan to generate more accurate and precise data?

• John and Katrina should carry out the investigation multiple times and compare and combine the data from each trial

• Nothing, John and Katrina’s investigation was as accurate and precise as possible

• John and Katrina should carry out the investigation multiple times, using different substances each trial

• John and Katrina should time how long the investigation takes them to complete

Multiple Choice

6. While carrying out the investigation, what observations should John and Katrina watch for when they combine the substances to help determine if a chemical reaction occurred or not?

• Bubbles forming indicating a gas formed

• The substances become warmer indicating that heat is being released

• Color changes in the substances

• All of the above would help determine if a chemical reaction occurred or not

Multiple Choice

7. Based on the data table, which answer helps you explain why substance 1 and 2 are different substances?

• Substance 1 and 2 have different masses, one being 50 and the other 100.

• Substance 1 has a boiling point of 1,665 and substance 2 has a boiling point of 227

• Substance 1 has a volume of 83.33 and substance 2 has a volume of 7

• Substance 1 has a density of 0.000089 and substance 2 has a density of 1.2

Multiple Choice

8. Use this data table to determine the identity of substance 1. Compare the patterns from John and Katrina's data table.

• Substance 1 is zinc because the density and boiling point are the same.

• Substance 1 is zinc because the mass is the same but the density is different.

• Substance 1 is aluminum because it has the same mass.

• Substance 1 is aluminum because its a metal.

• Substance 1 is copper because it’s the only substance that is bronze.

Multiple Choice

9.  Make a prediction to what you think would happen if you increase the amount of substance 1 in John and Katrina’s investigation.

• The color of substance 4 would change due to more silver present in the combination.

• There will likely be more bubbles indicating the presence of more gas.

• No change would occur because no matter how much of a substance you have the same reaction will always occur.

• The mass of substance 3 decreased because you added more of another substance.