Calculations

Question 1

mole definition

Answer 1

6.022x10^23 particles of a substance

Question 2

relative atomic mass definition

Answer 2

average mass of an atom on a scale where the mass of Carbon-12 is exactly 12

Question 3

moles eqn

Answer 3

mass= MrxMol

Question 4

ideal gas equation and units

Answer 4

pv=nRT
p=kPa
v=m^3
T=K

Question 5

empirical fomula

Answer 5

simplest ratio of atoms of each element in a compound

Question 6

equation for diluting concentration

Answer 6

new conc.= og conc. x og volume/new volume

Question 7

percentage yield eqn.

Answer 7

% yield= actual yield/theoretical yield x 100

(in moles)

Question 8

% atom economy eqn.

Answer 8

% atom economy= mass of useful product/ total mass of product x 100

Question 9

why do chemists want a high atom economy

Answer 9

maximum mass of reactants end in desired product (minimises by-prodct)

Question 10

why do chemists want a high % yield

Answer 10

so there is an effiecient conversion from reactants to products

Question 11

measurement vs reading

Answer 11

reading taken from a single value, measurement taken from the difference between two values

Question 12

% uncertainty calculation

Answer 12

% uncertainty= uncertainty/ total value measured x 100

Question 13

if % uncertainty is larger than the calculated value from apparatus

Answer 13

there is error in other areas of the experiment