1.

Which of the following is not a physical property used in the

dichotomous key to identify various minerals?

A. Color B. Acid Reaction

C. Hardness

D. Cleavage

Does the

metal

have a

gray or

silver

streak?

Yes

Is the

metal

harder

than 5.5?

Yes Does the metal

attract a magnet?

Yes Magnetite

No

No

Does the metal

have cubic

cleavage?

Yes Galena

No Graphite

No

Is the

metal

harder

than 5.5?

Yes Pyrite

No Is the metal

goldish-green?

Yes Chalcopyrite

No Copper

8th Grade Science Unit 1 Pre-Test

2. A scientist has three unlabeled samples of metals. He wants to

determine the identity of each metal. His observations are

recorded in the data table below. Use the data table (below)

and dichotomous key (from question # 1) to identify the three

metals.

A. Mineral #1-Galena

Mineral #2-Copper

Mineral #3-Graphite

B. Mineral #1-Copper

Mineral #2-Graphite

Mineral #3-Chalcopyrite

C. Mineral #1-Copper

Mineral #2-Pyrite

Mineral #3-Magnetite

D. Mineral #1-Copper

Mineral #2-Pyrite

Mineral #3-Galena

Sample # Streak Hardness Magnetic Color Cubic

Cleavage

1 Red 3 No Red-

Brown No

2 Greenish-

Black 6.5 No

Brass-

Yellow No

3 Silver-

Gray 2.5 No Gray Yes

3. A student designs an experiment in which they will observe

sugar as it is heated and burns. The student predicts that a

chemical reaction has occurred. Which of the following would

provide evidence that a chemical reaction has occurred?

A. Heat is added to the sugar crystals. B. The sugar melts and becomes a liquid.

C. The temperature of the sugar increases. D. Gas is produced as the sugar turns black.

4. Cassandra filled an empty 300 milliliter flask with 5 grams of

water. She put a cork in the flask and placed it on a sunny

windowsill. After some time, the water evaporated into a gas.

What was the mass of the water vapor in the flask after being

placed in the sun?

8th Grade Science Unit 1 Pre-Test

5. If a chemical reaction such as photosynthesis begins with 6

atoms of carbon (C), how many atoms of carbon (C) should be

in the products?

A. 12 atoms of carbon (C)

B. 6 atoms of carbon (C)

C. 3 atoms of carbon (C)

D. 2 atoms of carbon (C)

6. A teacher asks a student to write the chemical equation for the

reaction that occurs between Magnesium and Oxygen. The

student’s response is shown below.

Mg + O2 MgO

The equation is not balanced correctly. Which of these is a balanced equation?

A. 2Mg + O2 MgO2

B. 2Mg + 2O Mg2O

C. Mg2 + O2 Mg2O D. 2Mg + O2 2MgO

7. A liquid with a known temperature was poured into a

container. After 30 seconds, a second liquid with the same

temperature was added to the container. The change in

temperature was recorded and displayed in a graph.

Based on the data above, which of the following conclusions

could be made about the reaction that occurred between the

two liquids?

A. An endothermic reaction occurred because the final temperature was

less than the initial temperature.

B. An exothermic reaction occurred because the final temperature was

greater than the initial temperature.

C. An endothermic reaction occurred because final temperature was

greater than the initial temperature.

D. An exothermic reaction occurred because the final temperature was

less than the initial temperature.

8th Grade Science Unit 1 Pre-Test

Final Temperature Reading

Initial Temperature Reading

8. Which of the following illustrates what happens to the

temperature during an endothermic reaction?

9. A student observed that the rate of a chemical reaction

increased as the temperature of the system increased. Which of

the following statements best explains why thermal energy

caused an increase in the reaction rate?

A. The surface area of the product particles decreased.

B. The collision rate of the reactant particles increased.

C. The concentrations of the reactant particles increased.

D. The concentrations of the product particles decreased.

10. What happens to food during digestion that allows it to be converted into energy for a body to function?

A. Food is converted into oxygen for body cells to use as energy.

B. Food particles are left whole and energy is absorbed through digestion.

C. Food molecules are rearranged so that they can be used by body cells

to create energy.

D. Food particles create energy by being pumped by the heart throughout

the body.

8th Grade Science Unit 1 Pre-Test

This is a constructed response question.

Use the following space for pre-writing, but you must be sure to write your answer on the lines provided.

A group of students do an activity with baking soda and vinegar.

The steps of the activity are listed below.

1. Pour 100 g of vinegar into a flask.

2. Measure the temperature of the vinegar.

3. Add 10 g of baking soda to the flask.

4. Observe as the contents of the flask fizz (produce bubbles).

5. Measure the temperature of the contents of the flask and observe any change in temperature.

a. Describe one piece of evidence that a chemical reaction occurs when

baking soda is added to vinegar.

b. What should be the total mass of all the products of the reaction?

Show your calculations or explain your answer, and include units in your answer.

After the fizzing stops, the students determine that the liquid in the flask has

a mass of 105 g.

c. Describe how to change the activity to show that the total mass of all

the products is the value you calculated in part (b). Explain your reasoning.

Use this box to write your final draft.