Natural Science

Controlled Variables are things we keep the same.
Independent Variables are the things we choose to change.
Dependent Variables are observations of the effect.


Force: A push or a pull. They can cause movement, change speed, direction, shape or stop motion.
You get four main types of forces: Gravity, Frictional, Mechanical and Electrical. Force is measured in Newtons.


Mass: Amount of matter present in a body. Remains the same at any given place, measured in Kg's


Weight: The force which a given mass feels due to gravity. Measured in Newtons.

Work=Force x distance
Force=Work / distance
distance=Work/Force


Energy= Power x time
Power = Energy/time
time=Energy/Power








 Therefore: Power=Work/time=force x distance over time


Work: measured in Joules
1 Joule=1 Newton x 1 Metre


Power: Measured in Watts
1 Watt=1 Joule / 1 second


Chem
there are 3 stages of matter 

Matter is shown on the periodic table of elements. This is arranged so that the Horizontal Periods have an increasing atomic number, and the Vertical groups have similar properties and valencies.


We need to know the first 20 elements which are:
Hydrogen (H), Helium (He), Lithium (Li), Beryllium (Be), Boron (B), Carbon (C), Nitrogen (N). Oxygen (O), Fluorine (F), Neon (Ne), Sodium (Na), Magnesium (Mg), Aluminium (Al), Silicon (Si), Phosphorous (Ph),Sulphur (S), Chlorine (Cl), Argon (Ar), Potassium (K), Calcium (Ca)


Two or more elements group together to form compounds. Elements are combined in a fixed ratio (ie table salt is always NaCl). They are formulae that are given names (NaCl=Sodium Chloride) and they are worked out using Valency, or "bonding ability".


Valency is worked out using the Vertical groups. If you ignore the transition metals (which we do at this stage) there are eight  groups. Groups one to four have those respective abilities, ie group two's ability is two. Groups 5-8, you subtract the number from 8 to get the valency...ie group 6: 8-6=2, therefore the  bonding ability is 2. Group eight, the noble gases, have no bonding ability.


Chemical equasions always have to be balanced-they have to have the same number of each atom on either side. 
eg 1) Magnesium + Oxygen --> magnesium oxide

Mg   +   O₂    à MgO

There are 2 Oxygen atoms on the left, but only one on the right.

We can’t make it MgO₂, because that isn’t the formula for Magnesium oxide.

So we have to make it Mg   +  O₂  à  2MgO

But now we have more Magnesium on the right than the left.

2Mg  + O₂   à 2MgO

And we are balanced!

Radicals are elements that only exist as compounds, and not by themselves. For example, Carbonate is a radical. You can't just get carbonate, it has to have something with it, eg Calcium carbonate.

The 3 acids we need to know are:

Sulphuric acid – H₂SO₄

Nitric Acid – HNO₃

Hydrochloric Acid - HCl

Acids and Bases formulae

Acid + Base --> Salt + A water

Acid + Metal --> Salt + Hydrogen

Acid + Carbonate --> Salt + Water + Carbon Dioxide

Metal + Oxygen --> Metal Oxide

Non-Metal +Oxygen --> Non-metal oxide.

Indicators : Litmus turns acid blue and alkalines pink

The universal indicator 

Ores

Galena ---- Lead

Malachite----Copper

Bauxite --- Aluminium

Haematite --- Iron