C1 Flashcards
What are atoms?
All substances are made up of tiny particles called ATOMS. There are about 100 different types of atoms found naturally on Earth.
What are elements?
A relatively small number of substances are made up of only one type of atom.
What’s in the periodic table?
The symbols in the periodic table represent atoms. For example, O represents an atom of oxygen and Na represents an atom of sodium.
The elements in the table are arranged in columns, called GROUPS.
The ‘staircase’ drawn on the right of the periodic table in bold black is the dividing line between metals and non-metals. The elements to the left of the line are the metals. Those to the right of the line are the non-metals. However, a few elements lying next to the dividing line are called metalloids or semi-metals, as they have some metallic and some non-metallic properties. Examples include silicon, Si, and germanium, Ge, from Group 4.
What are compounds?
The vast majority of substances you come across are not elements. They made up of different types of atom bonded together.
What are all atoms made up of?
Tiny central NUCLEUS with ELECTRONS orbiting around it.
What is a balanced equation?
There is the same number of each type of atom on both sides of the equation.
What is the Law of conservation of Mass?
The total mass of the products formed in a reaction is equal to the total mass of the reactants.
What are state symbols?
They are used for solids, liquids and gases. They add extra information to the equation.
What is a mixture?
A mixture is made up of two or more substances (elements or compounds) that are not chemically combined together.
What are compounds?
Compounds have a fixed composition (the ratio of elements present is always the same in any particular compound).
Chemical reactions must be used to separate the elements in a compound.
There are chemical bonds between atoms of the different elements in the compound.
What are mixtures?
Mixtures have no fixed composition (the proportions vary depending on the amount of each substance mixed together).
The different elements or compounds in a mixture can be separated again more easily (by physical means using the differences in properties of each substance in the mixture).
What are the four different types of separation techniques?
Filtration
Crystallisation
Distillation
Chromatography
What is Filtration?
The technique of filtration is used to separate substances that are insoluble in a particular solvent from those that are soluble in the solvent.
What is crystallisation?
Crystallisation separates a soluble solid.
What is distillation?
A solution is heated and boiled to evaporate the solvent. The vapour given off then enters a condenser. This is an outer glass tube with water flowing through it that acts as a cooling ‘jacket’ around the inner glass tube from the flask. Here the hot vapour is cooled and condensed back into a liquid for collection in a receiving vessel.
