Physical And Chemical Changes Flashcards
What is a physical change?
A change in which no new substance is formed
What is a chemical change?
A change in which at least one new substance is formed
Give an example of a physical change.
Changing the state of a substance, e.g., melting lead
What is an example of changing physical appearance in a physical change?
Grinding limestone into powder
What is an example of dissolving a solid in a liquid?
Sugar in water
What is an example of separating mixtures in a physical change?
Filtering sand from water
What happens when green copper carbonate is heated?
It forms a black solid, copper oxide, and a colourless gas, carbon dioxide
What is produced when burning silvery magnesium ribbon?
A white powder, magnesium oxide
What are common signs indicating a chemical change?
- Gas is involved
- A solid (precipitate) forms when two solutions are mixed
- A change in colour happens
- Significant change in temperature occurs
- A solid disappears
- An odour is produced
In a chemical reaction, what are the starting substances called?
Reactants
In a chemical reaction, what are the substances that are formed called?
Products
True or False: A chemical change is easily reversed.
False
True or False: A physical change involves a large output of energy.
False
What is an example of a difficult to reverse change?
Unboiling an egg
What type of energy changes are involved in physical changes?
Relatively small energy changes
What type of energy changes are involved in chemical changes?
Generally a large input and output of energy
