Please enable JavaScript.
Coggle requires JavaScript to display documents.
6.2 Compounds and Mixtures (Compounds (Molecular Compounds (All the…
6.2 Compounds and Mixtures
Compounds
Every compound has a unique set of properties, they are usually very different and form the properties of the elements that make them
Some compounds are made up of molecules-such as water, wax and vegetable oil, each molecule in a compound contains two or more different types of elements
Most substances you encounter everyday are made up of more than one type of atom these forms of matter are known as compounds
Some compounds form crystal lattices(table salt is made of a lattice of sodium and chlorine atoms, while beach sand is a lattice of silicon and oxygen)
Molecular Compounds
All the molecules in a compound are identical in size and shape, and have the same number of atoms
Chemical formulas represent the molecules of a compound
The chemical formula is also known as a molecular formula since it describes how many of each tom make up the molecule
The number of each type of atom in the compound is written in subscript
Carbon monoxide has the formula of CO which means it has one carbon atom and one oxygen atom
Molecules of other compounds such as some plastics contain thousands of atoms and can stretch several metres long
Lattice compounds
Atoms are bonded very strongly to each other, which makes these compounds usually be hard solids at room temperature
Chemical formulas for lattice compounds are different fro the molecular formulas used for molecules
Compounds can also form crystal lattices (table salt and beach sand)
The scientific name for table salt is sodium chloride, its chemical formula is NaCl from this you can see table salt is made fro sodium(Na) and chlorine(Cl), the formula shows that there is one sodium for each chlorine atom in the lattice
The chemical formula for beach sand is SiO2 which means there is one silicon atom for every two oxygen atoms
Compounds are substances which consist of 2 or more elements which are chemically bound togethor
Mixtures
Substances that make up the mixture can be separated easily
Salt was is a mixture of table salt and water, you can seperate the salt from the water by heating the water and evaporating it leaving behind the crystals
A mixture is made up of more than one substance, where the substances are chemically bonded togethor
Anything that has a list of ingredients such as shampoo or soft drink, is a mixture
Everyday mixtures
Solutions are formed when a solid dissolves in a liquid in a solution: the dissolving solid is known as the solute, the liquid in which the solute dissolves is known as the solvent
Water-based mixtures are referred to as aqueous solutions(sugar dissolves in water to form an aqueous sugar solution)
There are many different types of mixtures that you use everyday, a common type of mixture is a solution
There are everyday mixtures other than solutions, smoke is a mixture of fine solid particles mixed with air
Milk is an example of an everyday mixture where solid particles are suspended in a liquid, although the particles in milk are solid, they are very small and will never settle to the bottom of the liquid
Describing mixtures
Mixtures can be often only be discrebe as a list of ingredients
Solutions of substances dissolved in water are commonly used in chemistry and so these mixtures have been given formula scientific names (when copper(II) sulfate is dissolved in water, the solution is written as CuSO 4 (aq). In this formula, the (aq) stands for aqueous, which means dissolved in water)
In a mixture there are a variety of substances, and the amount of each substance can vary, so you can not right chemical formulas for mixtures
The concentration of a solution measures how much of a substance is in the solution
Concentration can be given in a number of ways, in a laboratory concentration is usually expressed using a unit called molar(M)
Alloys
Iron is cheap to produce but is soft and rusts easily, making less useful, steel alloys vary greatly depending on what the iron is mixed with
It is impossible to write a chemical formula for steel, because steel is a mixture of iron and other substances, there ore steel can only be described by listing the substances in the alloy
Alloys are a mixture of a metal with other metals or non-metals, they are important because they often have very different and useful properties compared to pure metal
Adding small amounts of carbon to iron produces the alloy steel which is strong and useful for building
Adding chromium and nickel produces stainless steel, which stop sit rusting