2.1 atomic structure and isotopes

what are isotopes?

atoms of the same element with the same number of protons but a different number of neutrons

what is relative atomic mass?

the weighted mean mass of an atom of an element compared to 1/12 of the mass of carbon-12

why is carbon-12 the standard measurement of relative mass?

1/12 of carbon-12 = 1

what is relative isotopic mass?

the mass of an atom of an isotope compared to 1/12 of the mass of carbon-12

what is avagadros constant?

6.02 x 10^23

what is molar gas volume?

the volume occupied by 1 mole of any gas

what is the standard molar gas volume?

24dm^3

what is the idea gas equation?

pV = nRT

what assumptions are made with the ideal gas equation?

• no intermolecular forces

• negligible size of gaseous molecule

what is the conversion of atmospheres (atm) to pascals (Pa)?

1atm = 101kPa = 101,000Pa

what is the conversion of m³ to cm³ and dm³?

dm³ = 10^-3

cm³ = 10^-6

what is the conversion of K to degreeC?

1degreeC = K(+273)

what is water of crystallisation?

water molecules that form an essential part of the crystalline structure of a compound.

The product created is called a hydrated salt

what is the equation for percentage yield?

% yield = actual yield / predicted yield x 100

in reactions how can product be lost?

• filtration / evaporation / transferring liquids

• equilibrium not to completion (in reversible reactions)

• reactants not pure

• side reaction leading too by-products

why is percentage yield important?

• reduces waste

• uses less raw materials

• uses less energy

• increases profit

what is the equation for atom economy?

Mr of desired product / sm of Mr of all products x 100

what is the atom economy of an addition reaction?

100%