Chapter 3 AMOUNTS OF SUBSTANCES

Created by

Amber Williams

Cards (20)

What is Avogadro's number?
6.022 x 10^23
What equation links moles, Mr and mass?
$Moles\ n=$ $\frac{Mass\ \left(g\right)}{Mr}$
What is relative formula mass?
The mass of a formula unit with a mass of an atom of carbon-12
What is relative molecular mass?
The mass of a molecule compared to the mass of an atom of carbon-12
What is empirical formula?
Simplest whole number ratio of atoms of each element
What is the water of crystalisation?
The water that is released when a salt is dehydrated
What are the assumptions when doing calculations involving water of crystalisation?
All the water has been lost
No further decomposition takes place
What equation links moles, volume and concentration?
$Moles,\ n\ =$ $concentration\ \left(moldm^3\right)\times volume\ \left(dm^3\right)$
What is molar gas volume?
The volume per unit mole of gas volume at RTP
What is the ideal gas equation?
pV=nRT (where p=Pa, V=m3, n=mol, T=K, R=gas constant)
What is stoichiometry? 
The ratio of moles in a reaction
What is the stoichiometry used for?
To see how much product is produced and what amounts are required in preparation
What is a limiting reagent?
The reactant that is completely consumed in a chemical reaction and limits the amount of product that can be formed.
How is percentage yield calculated?
Percentage yield is calculated by dividing the actual yield by the theoretical yield and multiplying by 100.
What is theoretical yield?
Maximum possible amount of a product
What is actual yield?
How much is actually produced
Why might theoretical yield be produced?
Incomplete reaction
Side reactions taking place
Products lost during purification
What is atom economy?
A measure of how well atoms are being used in reactions
What does a high atom economy mean?
Waste is minimised and the reaction is more sustainable
How is atom economy calculated?
Atom economy = $\frac{sum\ of\ Mr\ of\ desired\ products}{sum\ of\ Mr\ of\ all\ products}\times100$