amount of substance

Question 1

what is relative atomic mass?

units?

Answer 1

(Ar)
the average mass of an atom of an element relative to the 1/12th the mass of an atom of ¹²C

Question 2

what are isotopes?

Answer 2

atoms thar have the same no. of protons but dfiferent of neutrons.

Question 3

calculating Ar

Answer 3

(mass isotope x*abndce%)+(mass isotope y*abndce%)

100

if abundance values ain’t %, just use sum of values

Question 4

what is relative atomic molecular mass?

units

Answer 4

(Mr)

the mass of a molecule, relative to 1/12th mass of an atom of ¹²C

g. mol^-1
i. e. simple covalent molecules

Question 5

what is relatie formulae mass?

Answer 5

(RFM)

the mas of the formulae, relative to 1/12th of an atom of ¹²C

i.e giant ionic compounds

Question 6

what is a mole?

Answer 6

a measure of an amount of a substance

no. of atoms in 12g of ¹²C
6. 02*10²³ of atoms/molecules= 1 mole

Question 7

moles, mass, and molar mass equation

Question 8

finding .xH₂O?

Answer 8

find no. of mol of salt and the no. of mol of water

divide both by the smallest no. to give ratio (always the salt)

Question 9

moles and solutions

equation?

units of conc?

1 dm³=?

Answer 9

no. of moles = conc * vol

n=mol.dm^-3*dm³

1 dm³=1000cm³

Question 10

x is produced by reacting y with z.

what mass of x is made with [a]kg of y?

Answer 10

1) find the no. of moles of smthg
2) stochimetry (e.g. dividing 0.333 by 3 to make nice ratios)
3) convert using moles=conc*vol

Question 11

finding limiting reagent?

Answer 11

use actual example

Question 12

molar gas volume equation?

Answer 12

1 mole of any gas occupies 24 dm³

^therfore

vol=no.of moles*24

Question 13

ideal gas equation?

Answer 13

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