amount of substance

Question 1

what is a diatomic molecules

Answer 1

atom which only exist in twos

eg, N2, O2, F2, CL2, Br2, I2, H2

Question 2

what’s Avogadros constant

Answer 2

6.022x10^23

Question 3

how do you calculate number of particles

Answer 3

moles x avogadros constant

Question 4

calculate relative atomic mass (Ar)

Answer 4

average mass of one atom
_____________________________
1/12 the mass of carbon 12

definition - the average mass of the atom compared to carbon12

Question 5

calculate relative molecular mass (Mr)

Answer 5

average mass of one molecule
_________________________________
1/12 the mass of carbon 12

definition - the average mass of the molecule compared to carbon12

Question 6

moles =

Answer 6

= mass (g)
_______________
Mr

Question 7

mass =

Answer 7

moles (g) x Mr

Question 8

percentage yield =

Answer 8

actual
____________ x100
theoretical

Question 9

moles in solution

concentration =

Answer 9

moles
________________
volume (dm3)

Question 10

moles in solution

moles =

Answer 10

concentration x volume(dm3)

Question 11

what does concordant mean ?

Answer 11

+/- 0.1 of one another (between 2 results that are next to each other)

Question 12

percentage error =

Answer 12

error in equipment
_____________________ x100
amount measured

you can measure total titrations error if add all percentage errors together

Question 13

ideal gas equation =

Answer 13

PV = nRT

P = Pressure - Pa
V = Volume - m^3
n = Number of moles
R = molar gas constant - (8.31jk^-1mol^-1
T = Temperature - Kelvin (c* + 273)

Question 14

what is the empirical formula of a compound

Answer 14

its the simplest whole number ratio of atoms of each element

C H2 O

Question 15

what is the molecular formula of a compound

Answer 15

its the actual number of atoms of each element

C6H12O6

Question 16

how do you calculate empirical formula

Answer 16

1) divide each elements mass by the same (elements Ar) = number of moles

2) which ever has the smallest mole number - divide all moles by that (smallest) mole

3) this enables you to determine the smallest number ratio (make sure its whole numbers)

Question 17

% Atom economy =

Answer 17

mass of desired product
___________________________ x 100
total mass of reactant