Chemistry - The Mole

Front 1

what is Avogadro's constant?

Back 1

its the number of atoms per mole of the carbon-12 isotope

Front 2

how is Avogadro's constant represented?

Back 2

Na = 6.02 x 10*23

Front 3

what is the definition for 'amount of substance'

Back 3

the quantity whose unit is the mole

Front 4

define the term 'mole'

Back 4

the amount of any substance containing as many particles as there are carbon atoms in exactly 12 g of the carbon-12 isotope.

Front 5

how do you work out the mass of one mole of any element?

Back 5

its the relative atomic mass in grams

(on the periodic table, the number above the element symbol)

Front 6

define the term 'molar mass'

how is it represented?

Back 6

its the mass per mole of a substance

gmol-1

Front 7

how do you work out the molar mass of an element?

Back 7

if in a compound/formula unit, then:

add together all the relative atomic masses, not forgetting the units gmol-1

Front 8

in 48 g of Carbon, how many moles are there, bearing in mid that the relative atomic mass for carbon is 12?

what's the formula needed?

Back 8

n=m/M

so its n=48/12 which = 4

the answer = 4 mols

Front 9

define the term 'molar volume'

Back 9

the volume per mole of a gas

Front 10

what are the units for molar volume?

Back 10

dm-3mol-1

Front 11

at room temperature and pressure, what is the approximate molar volume of a gas?

is it the same for all gasses?

Back 11

24 dm-3mol-3

yes, doesn't matter which gas, they all have the same molar volume at room temperature and pressure

Front 12

how do you work out the amount, in mol, for gasses at room temperature?

for dm^3 and cm^3

Back 12

for dm^3 :
n (number of moles) = V (volume) / 24.0

for cm^3 :
n = v/24000

Front 13

if you're trying to work out the volume, how do you rearrange the formula?

Back 13

V = n x 24

or

V = n x 24000

Front 14

define the term 'concentration'

Back 14

the amount of solute, in mol, dissolved per 1 dm^3 of solution

Front 15

to work out the amount of moles, of a solution, what are the equations?

Back 15

n = c x v (in dm^3)

n = c x v / 1000 (in cm^3)

Front 16

what is a standard solution?

Back 16

a solution of known concentration

Front 17

what does concentrated mean?

what does dilute mean?

Back 17

a large amount of solute per dm^3

a small amount of solute per dm^3

Front 18

if you need to make up a standard solution, you will need to weigh out a substance. How do you do this?

Back 18

1) consider the volume of solution needed
2)work out the amount, in mol, of solute needed
3) convert this amount of solute into a mass (g) so you know how much to weigh out