A level Chemistry

Now back to basics I know but its surprising how the simple stuff can catch you out! So lets get this party started: Electrons - have a negative charge and is equal to that of protons Protons - have positive charges and can be found as the smaller number under an element. Neutrons - has a neutral charge and is found out by taking the atomic mass (smaller number) away from the relative atomic mass (the bigger number) Some atoms are quite happy to stay on their tod without any need of bonding, these are known as 'noble gases'. These elements make up the group 0/8 on the periodic table and this purely means their outer shell is full of electrons so there is no need for any actual bonding to occur. Being that their outer shell is full they are extremely stable elements and almost never react because of this. However, as the group number decreases the less stable an element is, making group 1 very unstable. There are 3 types of bonding and as you have probably guessed they a

Previously in gas equations we learnt that - n=V/24000. There is one other side to this equation for when those hateful questions come up! As always we will run through this simply and easily but first we need to start off with the symbols that make up this equation: n =  as always is mol T = Temperature measured in K P = Pressure measured in KPa V = Gas volume measured in dm cubed R = The gas constant Now I understand that this may seem like a lot of info but let break this down: STP means the standard temperature and pressure which results in-      - Standard temperature being 298K     - Standard pressure being 100KPa As usual we don't question and in the legendry words of the Beatles 'Let it be' ... I should probably stop with the jokes! The other thing that is quite important that you know is the gas constant which is 8.314mol -1 K -1 and once again keep the previous sentence in mind! The actual equation for this is: PV = R x nT or Pressure x gas vo

So everything you were taught at GCSE by your teachers, yeah that was all a lie, completely forget that they lied to you! Electron shells aren't flat they are 3D and that issue with going past 20 electrons? Fret no more because we can now get past this, admittedly with a lot of work but what doesn't kill you makes you stronger! So these electron orbitals are filled with sub levels, remember the 2.8.8.2 formula? Well it turns out they were actually sub levels in an atom, here take a look: As you can see the shells are known as 'n' and the number of that orbital increases the further away it gets. Now not to confuse you but technically they are all on top of each other and the distance between each of these is miniscule! When drawing them though I recommended giving them space otherwise you are not going to be working with a lot! So lets take a deep look at this: Orbitals are known as S, P, D, F and so on but you don't really need to know any further for now. No

So these crystals are little balls of issues which require a lot of tissues! They are blue crystals when hydrated and a white powder when anhydrous. Here take a look for yourself at its hydrated form:   Hydrated - solid crystals contain water of crystallisation Anhydrous - contains no water of crystallisation Dehydration - removal of water of crystallisation Degree of hydration - the number of moles of water of crystallisation chemically bonded in 1 mole of the given compound   Now this is the part where you begin to hate on these little crystals as once again we are forced with maths, joy! So lets look at an example of this: Determine the formula of hydrated magnesium sulphate: Mass of hydrated salt MgSO₄  . 'X'H₂O = 4.312g Mass of anhydrous salt MgSO₄ = 2.107g Mass of H₂O = 2.205g   First calculate the amount of moles in the anhydrous salt (If you don't know how to do this check out my post on amount of substance to learn all about it)   Mola

This is simply used to show a formula ratio between different elements. If you know the mass of each element in a compound you can calculate its empirical formula. Remember from the amount of substance post that we learnt about an important equation: n = m / M                            n = Amount of substance                    m = Mass                    M = Molar mass Let works with an example to show the empirical formula: Analysis shows that 0.6075g of magnesium combines with 3.995g of bromine to form a compound. Ar is the mass number of a singular atom, in this case it would be: Mg = 24.3 Br = 79.9                                                                                         Mg   :   Br   This is where the ratio begins, starting with the mass divided by the molar mass. So I will do this separately first:   Mg = 0.6075 / 24.3   Resulting in 0.025   Br = 3.995 / 79.9   Resulting in 0.050 Ratio values do not have units so you don't need

When a reaction occurs there are two main elements in this: The reactants and the products . It is simply a matter of being aware of your elements and their groups, electrons and a little bit of simple brain twisting! Before we begin, it is important you know and understand these symbols and its just a matter of either you know it or you don't! (s)- Solid (l)- Liquid (g)- Gaseous (aq)- Aqueous Now lets try some simple equations! For ease and simplicity lets start from the bottom with H2O, now what do we know about this substance? Yup its that's flavourless thing that comes out of your tap which let be honest no one enjoys unless its with juice, tea or a hot chocolate. If you understand this just skip ahead, wouldn't want to waste your tyme ;) So water, let get it into its equation form: H2    +    O2    ---->    H2O So what the problem here? Did you spot it? Its unbalanced, every chemists nightmare! So how do we solve this? Well let me show ya! So here

Chemists use amount of substance for counting atoms. This uses moles to find out said substance by using relative atomic mass and the weight of the substance. This is represented by: n=m/M                       n=Moles                                   m=Mass                                   M= Molar mass (relative atomic mass) To find out molar mass of a substance you can look at a periodic table and looking at the mass number (larger number above the element) for example carbons mass number is 12 NOT 6 as this is atomic mass. A simple example of this would be using carbon. First try this on your own using the formula above, if you have trouble follow this through after writing the question down. How many moles are there in 48g of carbon? Now let run through this piece by piece and we will break it down and increase difficulty as we run through different examples. Returning to the original formula which is: n=m/M Looking at the periodic table of elements we can se

This is similar to amount of substance, however we are working with gases and gas volumes alone. This works effectively when the substance is held at RTP. When the volume is in cm cubed the equation is: n=V/24000       n=Moles                          V=volume                          As for the 24,000 just don't question it! If that's what they want, that's what they'll get! As usual we will go through some examples step by step. However, one thing you do need to know is RTP meaning room temperature and pressure. What amount, in mol, of gas molecules is in 72 cm cubed of any gas at RTP? This is simply plugged in: n=72/24,000= 0.0030 moles Now lets try something a little more brain tingling: What is the volume in, cm cubed, of 2.130 x 10 to the power of negative 3 mol of a gas at RTP? Once again we plug in the info we posses into the formula: 2.130 x10 neg 3=V/24000 We now need to rearrange this to form: V= 2.130 x 10 neg 3 x 24,000= 51.12 cm c