Chemistry Flashcards
Physical change
A change in a substance doesn’t change what the substance is, it only changes the appearance of a substance, not its chemical properties.
Give examples of physical changes
Changes in shape, size, and state of matter
Can all physical changes be reversed?
Some, but not all physical changes can be reversed
Give examples of how physical changes can be formed
Cutting, crushing, breaking
Chemical change
When a substance combines with another and a new substance is formed.
Give examples of chemical changes
Burning, rusting, decomposing
What happens in chemical reactions?
In a chemical reaction, the reactants combine together to form a new substance with different properties, energy can be given out in the form of heat or light and the change cannot be reversed.
Name some chemical reactions in living things
Digestion, respiration, photosynthesis
Word equation
They show the chemicals that react and are produced in a chemical reaction
Reactants
The substances that react together
Product
The new substances that are made in the reaction
Types of chemical reactions
When the reactants combine and form a new product and when the product breaks apart to produce 2 or more new substances
Burning
A chemical reaction in which a substance reacts with oxygen gas from the air, releasing heat and often light, and producing new substances
Is burning a physical or chemical change?
Chemical change
What is the new substance formed when burning?
Sometimes ash forms as the new substance
How can we compare the properties of reactants and products?
By comparing their physical state, color and chemical composition
What are the properties of magnesium?
It is soft and shiny, malleable, conducts electricity and is a element
What are the properties of oxygen?
It is a colorless gas, element and has no smell