Show Menu
Cheatography

Mole Calculations Cheat Sheet by

Conven­tions and Rules

* Molar mass is the mass of one mole of atoms in a substance.
* 1 mole of any gas is 24dm3 at r.t.p.
* Avogadro's Constant is the number of particles in one mole of any substance. The number is 6 x 1023.
* Relative Atomic Mass is the mass of one atom of an element compared to 1/12 of the mass of one carbon-12 atom.
* Relative Molecular Mass is the mass of one molecule of an element compared to 1/12 of the mass of one carbon-12 atom.
* Relative Formula Mass is the mass of one formula unit of an ionic compound. It is the sum of the Ar of all the ions in the formula unit.
* 1000cm3 = 1 dm3

Formula Triangles

Top
Bottom 1
Bottom 2
No. of Particles
No. of Moles
Avogadro's No.
Mass in Grams
No. of Moles
Molar Mass in g/mol
Volume of Gas in dm3
No. of Moles
24dm3
Mass in g
Volume in dm3
Mass Concen­tration in g/dm3
No. of Moles
Volume in dm3
Molar Concen­tration in mol/dm3
* To find top, multiply bottom values. To find bottom, take top divided by other bottom value.

1. No. of Particles // Moles // Avogadro's No.
2. Mass // Moles // Molar Mass
3. Volume // Moles // 24dm3
4. Mass // Volume // Mass Concen­tration
5. Moles // Volume // Molar Concen­tration

Concen­tration

* The amount of solute dissolved in a unit volume of the solution.
* Usually in g/dm3 or mol/dm3.
* Mol/dm3 is also called Molarity.
* 1M = 1 mol/dm3
 

Molecular Formula & Empirical Formula

Value
Element A
Element B
Mass in Grams
x
x
Molar Mass
x
x
Moles
x
x
Mole Ratio
x
x
1. Given % Compos­ition, find masses of both substances in 100g. If 70% is A and 30% is B, then there is 70g of A and 30g of B in 100g of AB.
2. Find molar mass using periodic table.
3. Find no. of moles by multip­lying mass and molar mass.
4. Divide all sides by the smallest number and round off to the nearest whole number to get mole ratio.
5. Molecular Formula is always a multiple of the Empirical Formula.

% Purity and % Yield

% Purity = Mass of Pure Substance / Total Mass x 100%

% Yield = Actual Mass / Theore­tical Mass x 100%

Limiting Reagents & Reactants in Excess

x
No. of Available Moles
vs
No. of Moles Needed
Limiting Reagents
No. of Available Moles
<
No. of Moles Needed
Reactants in Excess
No. of Available Moles
>
No. of Moles Needed
 

How to Find Limiting Reagents

A + 2B 2AB

1. Find no. of available moles for A.
2. Find no. of available moles for B.
3. Find no. of moles needed for A/B.
E.g. Moles needed for A = Available moles for B / 2
(Refer to mole ratio)

If moles available is < moles needed, then that reactant is the limiting reagent.
The concept of limiting reagents is the available moles for reaction vs the needed moles for reaction.

Mole Calcul­ations

Given
   
Find
Mass of A
Moles of A
Moles of B
Mass of B
Vol. of A
Moles of A
Moles of B
Vol. of B
Mass of A
Moles of A
Moles of B
Vol. of B
Vol. of A
Moles of A
Moles of B
Mass of B
Refer to mole ratio when converting Moles of A to Moles of B.
1 mole of any gas is 24dm3 at R.T.P.

Acids & Bases

Metal + Acid Salt + Hydrogen Gas
Metal Carbonate + Acid Salt + Water + Carbon Dioxide
Metal Oxide + Acid Salt + Water
Metal Hydroxide + Acid Salt + Water
Base + Acid Salt + Water (Neutr­ali­sation)
Alkali + Acid Salt + Water
Alkali + Ammonium Salt Salt + Water + Ammonia Gas
Alkali + Salt Metal Hydroxide + Salt
       
 

Comments

No comments yet. Add yours below!

Add a Comment

Your Comment

Please enter your name.

    Please enter your email address

      Please enter your Comment.

          Related Cheat Sheets

          Discrete Math Cheat Sheet
          Basics of Chemistry Cheat Sheet

          More Cheat Sheets by fongrsy