calculations quantitave

Question 1

what is law of conservation and mass

Answer 1

mass of reactants = mass of products

Question 2

mass will appear to increase if?

Answer 2

there is a gaseous reaction
- reacts with the 02 in the air

Question 3

mass will appear to decrease if

Answer 3

there is a gaseous product
- the gas will return into the air

Question 4

how to measure uncertainty for 1 measurement

Answer 4

1/2 the smallest scale division

Question 5

how to measure uncertainty for multiple readings

Answer 5

1/2 of the range

Question 6

how to work out mr

Answer 6

sum of atomic mass

Question 7

% in mass

Answer 7

mr of what you want / total mr X 100

Question 8

what is a mole

Answer 8

6.02 x 10 ^23

Question 9

how do you calculate the number of particles

Answer 9

number of moles X 6.02 x 10^23

Question 10

mass mr moles equation

Answer 10

moles = mass(g) / mr

Question 11

moles concentration volume 1000 equation

Answer 11

moles = C x V / 1000

Question 12

moles volume 24

Answer 12

vol dm^3 / 24 or vol cm^3 / 24000

Question 13

% yield equation

Answer 13

actual mass/ expected mass X 100

Question 14

% atom economy

Answer 14

% atom economy = mr of desired product/ mr X100

Question 15

why do u not get 100% yield

Answer 15

• side reactions
• reversible reactions
• impure reactions

Question 16

how to do titration

Answer 16

• add 25cm^3 of acid to conical flask using a pipette
• add a few drops of indicator ( phenolphthalein )
• fill burette with alkali
• add acid to alkali until it begins to turn pink
  -add dropwise at the end
• repeat until you achieve coordant results