GCSE Chemistry- C3 Quantitative Chemistry

What is relative atomic mass (Ar)?

the average mass of an atom of an element (relevant to Carbon 12)

What is the formula for relative mass (Ar)?

((isotope A x abundance)+(isotope B x abundance))/100

What is relative formula mass (Mr)?

sum of all relative atomic masses of all atoms in the formula

What is the formula for percentage by mass?

mass of (element/Mr) x 100

What is conservation of mass?

mass of reactants = mass of products

What is a mole?

6.02 x 10^23

What is Avogadro's constant

6.02 x 10^23

What is the formula for Moles using mass and Mr?

Mass= Mr x Mol

What is a limiting reactant?

a reactant that limits how much of a product can be made.

How do you find the limiting reactant?

the reactant with the least moles per the molar ratio

What is yield?

how much you can make; mass of products

What is theoretical

How much something should've been made

What is actual yield?

the amount something actually made

What is the formula for Percentage yield (how much made compared to the supposed amount)?

(actual mass/theoretical mass) x 100

Why might there not be 100% yield?

reactants may form unexpected products

some product may be lost when transferring

reactants may be impure

the reaction is incomplete

What is atom economy (atom utilisation)?

A measure of the amount of starting materials that end up as useful products

What does atom economy (atom utilisation) tell us?

how efficient a reaction is

Why is high atom economy important?

more sustainable, fewer natural resources- better for enviroment, less waste- cheaper

What is the formula for atom economy (%) ?

(Mr of useful products/sum of Mr of all reactants) x 100

What is concentration?

the number of particles in a certain volume

What is the formula for concentration using mass and volume??

Concentration= mass/volume

What is concentration measured in?

g/dm3 or mol/dm3

What is the formula for concentration using mol and volume??

Concentration= mol/volume

What is the volume of 1 mol of gas?

1 mol of gas = 24 dm3

What is the formula for volume of gas using moles?

Volume of gas (dm3) = moles x 24