7th U3L1 Review

What type of change occurs when a candle burns?

• A) Physical change

• B) Chemical change

• C) Both physical and chemical changes

• D) Neither

What do we call the substances formed as a result of a chemical reaction?

• Reactants

• Products

• Elements

• Mixtures

Which of the following indicates that a chemical reaction has occurred?

• A) A change in color

• B) The release of gas

• C) A change in temperature

• D) All of the above

Which property is used to identify a substance?

• Density

• Color

• Mass

• Volume

When vinegar and baking soda are mixed, what gas is produced?

• Oxygen

• Carbon dioxide

• Hydrogen

In a chemical reaction, what remains constant according to the Law of Conservation of Matter?

• Mass of products

• Number of gases

• Number of atoms

Which of the following is a sign of a physical change?

• Formation of a gas

• Change in temperature

• Dissolving sugar in water

• Color change

What happens to the energy during a chemical reaction?

• It is always released and discarded.

• It is always absorbed and used.

• It can be either absorbed or released.

• It is destroyed and released.

Which of the following is an example of a physical change?

• Burning coal

• Cooking an egg

• Melting ice

• Rusting iron

In a chemical reaction, what happens to the bonds between atoms?

• They break and form new bonds.

• They stay the same.

• They are created.

• They disappear.