R.2.1

Question 1

Pyramid for mass, density and volume

Answer 1

mass/density x volume

Question 2

What is an ideal gas?

Answer 2

A gas that obeys the ideal gas laws under all conditions

Question 3

When does a gas behave most like an ideal gas?

Answer 3

-At low pressures
-At high temps

Question 4

What is Van der Waal’s equation?

Answer 4

PV/nRT < 1
-If there volume of the gas particles isn’t negligible and there are attractive forces

Question 5

Ideal gas law formula

Answer 5

Mr = (m/PV) RT

Question 6

Define stoichiometry

Answer 6

Relationship between the amount of reactants and products

Question 7

How can we use the mole ratio of an equation to determine the masses of reactant and products?

Answer 7

1) Balance equation
2) Mole ratio
3) Work out reacting ratio with m= m x Mr
4) Insert data from the question and solve the ratio

Question 8

Steps to solve an unknown concentration after a titration

Answer 8

1) Find the moles: n=cxv
2) Compare the mole ratios n=n
3) work out x in n= x x v

Question 9

Define back titration

Answer 9

Method used when you cannot directly measure the amount of a substance

Question 10

How does a back titration work?

Answer 10

1) Add extra reactant
-Add more than what the sample needs so that some of the reactant will be left over
2) React whats left over
-Regular titration to measure how much of the extra reactant is left unreacted
3) Calculate the amount in the sample
-Subtracting the leftover reactant from what we started with can actually tell us how much of the reactant actually reacted with the sample

Question 11

Percentage yield formula

Answer 11

experimental yield/ theoretical yield x 100

Question 12

Define atom economy

Answer 12

measure of efficiency

Question 13

% atom economy formula

Answer 13

molar mass of desired products/molar mass of all reactants x 100