Quantitative chemistry

During a chemical reaction what’s important about the number of atoms

No atoms are lost or made so mass of products equals the mass of the reactants

What are ions

Atoms with a charge

Metals and non metals form what kind of ions

Metals - positive

Non-Metals - Negative

In an ionic compound charges on the ions have to…

Cancel out leaving the overall charge as 0

In working out the relative formula mass what is not used

The big numbers

How do you workout the percentage by mass

Ar over Mr multiplied by 100

How to workout number of moles

Moles = mass/Ar

How do you work out the number of moles

Moles = Mass/Mr

G Mr Mole

What is Avagadro’s constant

602000000000000000000000

or

6.02×10 ²³

How many molecules does 1 mole of hydrogen chloride have

Avagadro’s constant

6.02×1023

What is concentrations

The mass of a solute in a given volume of solution

What is a solute

A chemical that’s dissolved in a solvent

How to work out concentration

Mass/Volume

What are 3 reasons that you may not be able to obtain 100% yield

• Some product may be lost when separated from reaction mixture

• Some reactants may react in a different way

• Reversible reactions may not go to completion

How do you work out percentage yield

Mass of product made/mass of theoretical maximum

What is atom economy

The amount of starting materials that end up as useful products

Why is this good

• Save money

• Increase sustainability

What’s the equation for atom economy

Relative formula mass of desired products/sum of Rfm of all reactants x 100

How do you work out concentration in mol/dm3

Conc = moles/volume

How much volume foes 1 mole of gas take up at room temp and pressure

24dm³

what is room temp and pressure

temp - 20oC

pressure - 1atm