chemical and Physical Change

What is a physical change?

• A change that alters the chemical composition of a substance.

• A change that affects one or more physical properties of a substance without altering its chemical composition.

• A change that occurs only at high temperatures.

• A change that involves the formation of new substances.

What does it mean if the properties of substances change when mixed?

• It indicates that a chemical change may have occurred, suggesting that a new substance has formed.

• It means that the substances will remain unchanged after mixing.

• It suggests that the substances will evaporate when mixed.

• It indicates that the substances will dissolve completely in each other.

What is a chemical change?

• A process where substances combine or break apart to form new substances with different properties.

• A physical change that alters the appearance of a substance without changing its composition.

• A reaction that occurs only in the presence of heat or light.

• A method of separating mixtures into their individual components.

What happens to the mass of substances during a chemical change?

• The mass is lost during the reaction.

• The mass is conserved; the total mass of the reactants equals the total mass of the products.

• The mass increases due to the formation of new substances.

• The mass varies depending on the temperature of the reaction.

What is an example of a physical change?

• Melting wax is an example of a physical change.

• Burning wood is an example of a physical change.

• Rusting iron is an example of a physical change.

• Mixing sand and salt is an example of a physical change.

Why is it important to record properties before and after mixing substances?

• It helps to determine if a new substance has formed and to compare the properties of the mixtures.

• It is necessary for safety regulations during chemical experiments.

• It allows for the measurement of temperature changes only.

• It is required for legal documentation of chemical processes.

What is evidence that a new substance has formed?

• The resulting substance has the same properties as the original substances.

• The resulting substance is lighter than the original substances.

• The resulting substance has different properties or is heavier than the original substances.

• The resulting substance is in a different state of matter than the original substances.

What should remain constant in an experiment to test chemical changes?

• The temperature of the environment

• The substances that are combined in each experiment should be the same.

• The amount of light present during the experiment

• The size of the containers used for the reactions.

What is a reactant?

• A substance that is present at the start of a chemical reaction.

• A product formed after a chemical reaction.

• A catalyst that speeds up a chemical reaction.

• A byproduct that is released during a chemical reaction.

What is an example of a chemical change?

• Melting ice to water

• Exploding fireworks

• Dissolving sugar in water

• Boiling water into steam