OCR A 2.1.2 & 2.1.3 Amount of Substance, Compounds, Formulae and Equations 1"

how to calc water of crystallisation (experiment)

-measure mass of hydrated salt

-heat until no more water left

-anhydrous salt left

-measure mass of this

-the find mass of water and divide all known masses by the mr to find moles

-find molar ratio

ionic equation steps

-split aqueous substances

-cross out ions on both sides

mole

-way of measuring the amount of a substance

-6.02 ×10²³

-1 mole of Fe contains 6.02 ×10²³ atoms of Fe

how to find number particles from moles

mole, mass, mr equation

moles in sol equation

cm to dm

divide by 1000

ideal gas equation

standard conditions

-298K

100kPa

aqueous meaning

dissolved in water

empirical formula

simplest whole number ratio of elements in a compound

percentage yield

atom economy

-how efficient a reaction is

importance of atom economy

high atom economy:

-produce less waste

-less by-products; less time & money spent separating these from desirable product

-raw materials used more efficiently; more sustainable

percentage uncertainty formula

how to reduce percentage uncertainty

-more sensitive weighing scale (more dp)

-larger mass

how to find volume of gas from moles

-moles x 24(dm)/24000(cm)

molecular formula

actual number of atoms of each element present in a molecule