Unit 4 test Review

Which of the following always results from a chemical reaction?

• A. Fire
• B. Bubbles
• C. A new substance that is a solid
• D. A new substance that can be a solid, liquid, or gas

Physical properties....

• A. change the matter when studied
• B. can be observed and measured without changing the matter being studied
• C. include the ability to burn and rust
• D. are useless unless studied in a lab

Which of the following shows a balanced chemical equation?

• A. Al2O3 → 2Al + O2
• B. Al2O3 → 2Al + 3O2
• C. 2Al2O3 → 4Al + O2
• D. 2Al2O3 → 4Al + 3O2

Which of the following is a physical change?

• A. Burning Wood
• B. Baking Cake
• C. Rusty Nails
• D. Boiling Water

Which of the following is not an example of a physical change?

• A. Ice melting
• B. Cutting Grass
• C. Paper Tearing
• D. Egg Frying

When a candle is lit, the wick burns, the wax melts, the candle changes shape, and the air around the candle heats up. Which of the following is an example of a chemical change?

• A. the wick burning
• B. the wax melting
• C. the candle changing shape
• D. the air around the candle heating up

Imagine that you fill a bucket to the top with water and then place the bucket outside in freezing weather. Which of the following describes what will happen when the water in the bucket freezes?

• A. Iron turns to rust when it is exposed to oxygen
• B. When water boils, it turns into vapor, which is a gas
• C. When the water freezes it expands pushing some of the water over the edge of the bucket where it may freeze on the side.
• D. Gold can be spread out very thin to cover a large area

Which of the following describes an example of a material undergoing a chemical change to become another material with different characteristics?

• A. Iron turns to rust when it is exposed to oxygen
• B. When water boils, it turns into vapor, which is a gas
• C. Oxygen can become liquid at a very low temperature
• D. Gold can be spread out very thin to cover a large area

What will weigh more when a chemical change is complete? The reactants before the chemical reaction or the products after the reaction is complete?

• A. The product always weighs more than the reactant
• B. The reactant always weighs more than the product
• C. Both lose the same amount of mass after the reaction
• D. Both the reactants and products will weigh the same

The total amount of matter (atoms) before and after a chemical reaction, remains the same.

• True
• False
• It depends on whether it is a physical or chemical change