Chemistry is the study of matter. Matter is anything that has mass and occupies space.

When looking at diagrams like the ones above ask the following questions. Are all the atoms the same? YesNo It must be an element Are the molecules identical? YesNo compoundmixture

Elements are pure substances which cannot be broken down by simple chemical means into anything simpler. There are approximately 92 different elements found on earth. All matter is composed of combinations of these elements.

Compounds are pure substances which are composed of 2 or more elements combined in fixed ratios by mass. Mixtures are combinations of elements and compounds combined in variable ratios. Table salt (sodium chloride) is a compound and sea water is a mixture.

Most compounds names end in ide, ite or ate

Using the 2 questions previously given identify the following as Elements, Compounds or Mixtures and

Determine A - the total number of atoms B – The number of different kinds of atoms C – the total number of molecules D – the number of different kinds of molecules

Writing Formulas If the molecular model is Hydrogen atom Oxygen atom The formula is H2OH2O Keep in mind the same molecule could appear as Notice the element furthest left in the periodic chart is written first. If they're in the same column, the one further down goes 1st

Write Formulas for each of the following

phosphorus atom chlorine atom The formula is PCl 3

Carbon atom oxygen atom The formula is CO2CO2

carbon atom fluorine atom The formula is CF4CF4

sulfur atom bromine atom The formula is S 2 Br 2

Use the legend to write a formula for each of the following

chlorine aluminum bromine carbon fluorine nitrogen Use the legend to write a formula for each of the following

phosphorus iodine silicon carbon bromine fluorine silicon hydrogen

Draw diagrams for the following formulae MnSO 4 Ca 3 P 2 K 2 S AlPO 3

Sometimes the diagram will contain 2 or more molecules. In these cases this is how to adjust the formula.

carbon atom iodine atom The formula is 3C2I43C2I4 Coefficient

Phosphorus atom hydrogen atom oxygen atom The formula is 2H3PO42H3PO4

nitrogen atom hydrogen atom oxygen atom The formula is 4HNO44HNO4

Draw molecular diagrams using spheres to represent the following:

2H2SO32H2SO3 H is connected to O S is connected to O

4AsBr 5

Some formulas have brackets which are used to shorten what is written. For instance instead of writing CaCaCaPO 4 PO 4 Ca 3 (PO 4 ) 2 Ca P O

Ca 3 (PO 4 ) 2 The composition of this compound is 3 parts calcium 2 parts phosphorus 8 parts oxygen

Determine the compositions of each of the following compounds Mg 3 (PO 2 ) 2 3 parts magnesium, 2 parts phosphorus, 4 parts oxygen Fe(C 2 H 3 O 2 ) 3 1 part iron, 6 parts carbon, 9 parts hydrogen, 6 parts oxygen

Mn(C 2 O 4 ) 2 1 part manganese, 4 parts carbon, 8 parts oxygen Na 2 Cr 2 O parts sodium, 2 parts chromium, 7 parts oxygen (NH 4 ) 3 P 2 O 7

Identify the compositions of the following CaCO 3 1 part calcium, 1 part carbon, 3 parts oxygen Mg(ClO 3 ) 2 Mg ClO 3 ClO 3 1 part magnesium, 2 parts chlorine, 6 parts oxygen Al 2 (SO 4 ) 3 Fe(NO 2 ) 6

Al 2 (SO 4 ) 3 2 parts Aluminum 3 parts Sulfur 12 parts Oxygen Fe(NO 2 ) 6 1 part iron 6 parts nitrogen 12 parts oxygen

Cr(NO 3 ) 6 Zn(ClO 2 ) 2 Ag 3 (Cr 2 O 7 ) 5 (N 3 H 5 P 2 ) 4 (CaCl 3 P 4 ) 3 (C 5 H 12 O 21 ) 3 (Se 3 O 8 ) 4

Mixtures can have more than one kind of molecule. For these situations more than one formula is used.

2SO 3, 3SO 2

Mixtures can be classified into 2 different groups on the basis of whether or not they are uniform throughout (homogeneous) or whether or not there is more than one phase (heterogeneous). Homogeneous mixtures are called solutions. Heterogeneous mixtures are called mechanical mixtures.

Physical Properties can be observed without forming a new substance. They include colour, form, smell, texture, quantity, density, boiling point, melting point, conductivity, elasticity, ductility, malleability, etc. Quantitative physical properties are measured (mass, volume). Qualitative properties are not measured (colour for instance)