Magnetic Force
What is a physical change?
a. A change in the chemical composition of a substance
b. A change in the state of matter without changing the composition
c. A change that releases energy
d. A change that forms new substances
b. A change in the state of matter without changing the composition
1. What happens when food color is added to water?
a. It sinks to the bottom.
b. It mixes evenly throughout the water.
c. It changes the color of the water permanently.
d. It creates bubbles in the water.
b. It mixes evenly throughout the water.
1. What happens to the water when it is boiled?
a. It disappears completely.
b. It becomes steam.
c. It turns into ice.
d. It stays in liquid form.
b. It becomes steam.
Which of the following is an example of a chemical change?
a. Ice melting
b. Iron rusting
c. Water boiling
d. Sugar dissolving in water
b. Iron rusting
2. What is a pure substance?
a. A substance made of one kind of atom or chemically bonded atoms.
b. A mixture of different elements
c. A liquid that cannot be separated.
d. A gas that is always visible.
a. A substance made of one kind of atom or chemically bonded atoms.
2. According to the law of conservation of matter, what must remain unchanged during a chemical reaction?
a. The temperature of the reaction.
b. The speed of the molecules
c. The appearance of the substances.
d. The total amount of matter.
d. The total amount of matter.
5. Which substance undergoes a physical change when heated?
a. Propane
b. Iron
c. Water
d. Oxygen
c. Water
3. How can mixtures be physically separated?
a. By using chemical reactions.
b. By boiling them.
c. By heating or cooling them, or using magnets.
d. By letting them sit for a long time.
c. By heating or cooling them, or using magnets.
3. What is an example given about a physical process that demonstrates the conservation of mass?
a. Cooking pasta.
b.melting ice
c. Freezing water.
d. Rusting of a copper pipe.
d. Rusting of a copper pipe.
What happens to the molecular structure during a chemical change?
a. It stays the same
b. It breaks and forms new bonds
c. It only changes shape
d. It becomes a gas
b. It breaks and forms new bonds
4. Which of the following is an example of a homogeneous mixture?
a. Salad
b. Butter caramel
c. Sand and water
d. Seashells and cement
b. Butter caramel
4. What do enzymes in the body do with the food we eat?
a. They make it disappear.
b. They break it down into components.
c. They keep it intact.
d. They add mass to it.
b. They break it down into components.
When propane combusts, what type of change occurs?
a. Physical change
b. Neither
c. Chemical change
d. Both physical and chemical change
C. Chemical Change
5. What distinguishes a heterogeneous mixture from a homogeneous mixture?
a. Heterogeneous mixtures have a uniform composition.
b. Heterogeneous mixtures can be easily separated by chemical means.
c. Heterogeneous mixtures have distinct visible parts.
d. Heterogeneous mixtures are always liquids.
a. Heterogeneous mixtures have a uniform composition.
5. When water molecules change from liquid to gas, what happens to their mass?
a. It decreases.
b. It increases.
c. It stays the same.
d. It becomes unmeasurable.
c. It stays the same.