What is a compound
In chemistry, a compound is a substance made up of two or more different chemical elements combined in a fixed ratio. E.g = Water, carbon dioxide and table salt
What is a mixture
A mixture is composed of one or more pure substances in varying composition. E.g = Dirt and water (Mud)
How many classifications of mixtures are there
There are two main categories of mixtures: homogeneous mixtures and heterogeneous mixtures.
The classification of matter
Matter can exist in three forms or phases: solids, liquids, or gases.
physical and chemical properties
The general properties of matter such as color, density, hardness, are examples of physical properties.
Properties that describe how a substance changes into a completely different substance are called chemical properties.
metals
Metals are generally shiny, malleable, and hard. Metals are also good conductors of electricity
non-metals
an element or substance that is not a metal. They do not conduct electricity or heat very well
metalloids
they share characteristics of both metals and non-metals and are also called semimetals.
physical properties
A physical property is a characteristic of matter that is not associated with a change in its chemical composition. e.g = density, color, hardness, melting and boiling points, and electrical conductivity.
what is an element
An element is a fundamental item that can't be easily broken into smaller pieces. They only contain 1 type of atom.
what is a compound
A Compound is made up of two or more atoms of different elements joined by chemical bonds. A compound has very different properties from the elements from which it is made.
e.g CO2 = carbon dioxide e.g H20 = water
molecules
A Molecule is made up of two or more atoms joined by chemical bonds. The atoms joined together in molecules may be different or the same. Some elements exist as molecules – e.g. N2, O2 or H2
structure of an atom
Atoms consist of an extremely small, positively charged nucleus surrounded by a cloud of negatively charged electrons. In the neucleus there is neutrons and protons.
what is an atom
the smallest particle of a chemical element that can exist. everything is made from atoms. there to tiny to see.
how can compounds be separated
Mixtures can be physically separated by using methods that use differences in physical properties to separate the components of the mixture, such as evaporation, distillation, filtration and chromatography.
physical changes vs chemical changes
Physical = paper being folded into a paper aeroplane {folded} Chemical = logs turned into burning logs {combustion}
signs a chemical reaction is happening
-change in temperature -change in colour (eg rusting) -bubbles
everyday chemical reactions
rusting photosynthesis digestion
Photosynthesis
Photosynthesis is the chemical process used by plants to produce energy. The plant takes in Carbon dioxide and water, uses the energy of the sunlight, to produce Glucose and Oxygen.
Cellular respiration
The process by which organisms break down glucose into a form that the cell can use as energy
Pure substances
A substance that has a fixed chemical composition throughout is called a pure substance such as water, air, and nitrogen. A pure substance does not have to be of a single element or compound.
separating mixtures / methods
A separation process is a method that converts a mixture or a solution of chemical substances into two or more distinct product mixtures, you can do this by using a separating funnels and evaporation.
evaporation
Evaporation occurs when energy (heat) forces the bonds that hold water molecules together to break.
how many types of atoms are there
118
look at this electrical circuit by try and remember first
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Filtration
It is the process of filtering something. While preparing tea, a filter or a sieve is used to separate tea leaves from the water.