Science Chemistry Revision - Reactions, Elements, and Mixtures Flashcards
What is an irreversible change?
A change that cannot be undone or returned to it’s original form
What is a reversible change?
A change that can be easily undone and returned to it’s original form
What is a physical change?
A change in which the form or appearance changes, but no new substance is created
What is a chemical change?
A change in matter which produces one or more new substances
What happens to atoms in a chemical reaction?
The atoms are rearranged to create new substances
How do you know if a chemical reaction is taking place?
You may hear a loud bang or gentle fizzing, you may see large flames or tiny sparks
What is an element?
An element is a substance which consists of two or more of the same type of atom chemically bonded together.
What is a compound?
A compound is a substance consisting of two or more different elements chemically bonded together.
What is a molecule?
A molecule consists of two or more atoms bonded together
What is the difference between a molecule and an element?
An element is made up of only one type of atom whereas a molecule can be made up of different types of atoms
What is an atom?
The smallest particle of an element
What is the periodic table made up of?
Elements
What is meant by a mixture?
A mixture is two or more different substances that are not chemically joined together
What are the properties of compounds?
A compound has different properties to it’s elements
How do you find out if a sample of a substance is pure?
It is pure if it has a sharp melting point
How much of each substance does a compound contain?
The relative amount of each element cannot change
How much of each substance does a mixture contain?
The amounts of substances in a mixture can be changed
What are the properties of a mixture?
The substances in a mixture keep their own properties
