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R = 8.31Jk⁻¹mol⁻¹

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To change celcius to kelvin..... add 273 to degree celcius

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pV = nRT
p = pressure --> Pa or Nm⁻²
V = volume --> m³
n = moles
R = gas constant
T = temperature --> K

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Solute - what you're dissolving

Solvent - liquid

Solution- product

Often measure in g per 100g - g/100g
The density of water is 1gcm-3

Eg. Potassium nitrate has a solubility of 31.6g/100g water. Convert this to moldm⁻³
Mr KNO3 - 101.1
moles = mass ÷ mr
31.6 ÷ 101.1 = 0.313
0.313 x 10 = 3.13 moldm⁻³

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The concentration measures how much of a substance is dissolved(solute) per unit volume of a solution(solvent).
Can be called molarity.
Measured in 2 ways:
molar conc. - moldm⁻³ or mass conc. - gdm-3

moles = concentration(moldm⁻³) x volume(cm ³) ÷ 1000
n = cV÷1000

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Finding out the number of moles that will react together. Indicators are used to determine the end point in acid-based titrations. A burette measures a precise volume of liquid.

Eg. You have 50cm 3 of NaOH(base) solution. Using methyl orange indicator you titrate the base against a 0.10moldm⁻³ solution of H ₂ SO ₄. It takes 22.3cm ³ of 0.10moldm⁻³ H ₂ SO ₄ to neutralise 50.0cm ³ of NaOH.
What is the conc. of NaOH solution?
Step 1: BALANCE EQUATION
2NaOH + H₂SO₄ --> Na₂SO₄ + 2H₂O
Step 2: CONC. & VOL.
conc. acid - 0.10dm⁻³
vol. acid - 22.3cm³
conc. base - ?
vol. base - 50.0cm3
Step 3: RATIO
n=cv÷1000
0.10 x 22.3 ÷ 1000 = 2.23x10⁻³
2:1 NaOH:H₂SO₄
NaOH - 4.46x10⁻³
Step 4: CONCENTRATION
c=n x 1000 ÷ v
1000 x (4.46 x10⁻³) ÷ 50 =0.0892 moldm⁻³

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Burette - 0.1cm3

0.2° thermometer - 0.2°
3-place scale - 0.001g/1mg
%error = error ÷ quantity measured x 100
quantity measured....titre(burette), Difference in temp(thermometer), mass(balance)

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percentage yield =
actual product ÷ predicted product x 100
Usually has numbers in the question.

Ethanoic acid & ethanol have a 1:1 ratio. If 32.1g of acid are produced from the oxidation of 27.6g of ethanol, what is the % yield?
obtained÷actual x100
Mr ethnoic acid - 60.04
Mr ethanol - 46.06
moles=mass÷Mr
27.6÷46.06= 0.6
1:1    0.6:0.6
mass = moles x Mr
0.6 x 60.04 = 36.024
32.1÷36.024 x 100 = 89%

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atom economy =
required product ÷ mass of  reactants x 100
Usually has a chemical equation in the question.

Calculate atom economy for making iron.
Fe ₂ O ₃ + 3CO --> 2Fe + 3CO₂
required÷total x 100
111.6 ÷ 243.6 x 100 = 45.8%

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We use the volume of mass per mole, molar volume(Vm) E.g at 0°C & atmospheric pressure(STP) we can say that Vm=22.4dm ³ for any gas. This changes with temperature & pressure changes.
Volume of gas = moles x molar volume
V = M x Vm
Eg. 10g Zinc, reaction at STP, calculate hydrogen volume.
Zn + 2HCl --> H₂ + ZnCl₂
Zn:H₂ = 1:1 ratio
V = M x 22.4         N=M÷Ar
N = 10÷65.4 = 0.153mol
V = 0.153 x 22.4 = 3.43dm ³

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The mass of reactants and a balanced chemical equation means we can find the mass of the products.
Question. Fe ₂ O 3 is heated with carbon in a blast furnace. Fe ₂ O ₃ reduced to Fe & CO is produced. I receive an order of 50kg of Fe.
How much Fe ₂ O ₃ do I need?
Step 1: BALANCED EQ.
Fe₂O₃ + 3C --> 2Fe + 3CO
Step 2: RATIO
Fe₂O₃:Fe      1:2
Step 3: MASS --> MOLES
Fe Ar= 55.8 moles=mass÷Ar
kg-->g 50000g
50000÷55.8= 896mol Fe
Fe₂O₃ = 896÷2= 448mol
Step 4: MOLES-->MASS
mass=moles x Mr
448 x 159.6 = 71.5kg
Fe ₂ O ₃=159.6

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moles = mass ÷ Ar/Mr
The empirical formula is the simplest ratio.
Question. Find the empirical formula for the compound made of 75% C & 25% H.
moles= 75÷12= 6.25
moles= 25÷1.01= 24.7524
6.25÷6.25=1 24.7524÷6.25=4 *divide by smallest number*
1:4 compound - CH4
Question. 87.5% nitrogen & 12.5% hydrogen.
87.4÷14= 6.25     12.5÷1.01=12.4
6.25÷6.25=1        12.4÷6.25=1.98
1:2 NH₂
The Mr is 32.04.
Mr of NH2 = 16.02
NH₂ --->(x2) N₂H₄

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amount in moles(n) = mass(m) ÷ molar mass(M)

E.g What is the amount of sodium present in 0.23g of sodium?
Ar=23.0
23.0 ÷ 23.0gmol⁻¹ = 0.01mol

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6.02 x 10²³ mol⁻¹

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Made up of 2 isotopes - ³⁵Cl & ³⁷Cl. The Chlorine35 isotope is three times more likely than the Chlorine37 isotope.

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*Assume 100 atoms*
QUESTION EXAMPLE:
A mass spectrum of a hydrogen sample showed it to contagion 1H 99.20% and ²H 0.8000%.
Calculate the Ar of Hydrogen to 4sf.

(99.2 x 1) + (0.8000 x 2)
÷
100           = 1.008

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It is used to find....

the mass of different isotopes of an element

relative abundance of each isotope of an element

Ionisation
Vapour passes into the ionisation chamber. The particle sample is bombarded with a stream of electron & some collisions knock one(sometimes more) electrons to make positive ions.
Acceleration
an electric field accelerates the positive ions to a high speed.
Deflection
Different ions are deflected by a magnetic field by different amounts. Depends on....mass(lighter ions deflected more), charge on the ion(2+ are deflected more). These factors are combined into the mass/charge ratio
Detection
Beams of ions are detected electronically. Only ions with the right mass/charge ratio make it to the detector(other ions collide with the wall & pick up electrons becoming neutralised). These get removed by a vacuum pump. The signal often correct ions is amplified & recorded.

Ions need a free run through the machine without hitting air molecules, so a vacuum is needed.