C4 Chemical calculations Flashcards
How do you calculate the number of moles in a substance?
Moles = mass (g) / Mr
What is Avogadro’s constant?
6.02 x 10^23
What is the limiting reactant?
The reactant that gets used up first in a reaction
How do you calculate percentage yield?
Mass of product produced/maximum mass of product produced
List the factors that can effect percentage yield (3)
Product being left in apparatus, reversible reactions not going to completion, reactants may produce unexpected reactions
Why is using reactions with higher yields good?
It conserves resources and reduces waste
How do you calculate percentage atom economy?
Mr of desired product/sum of Mr of reactant
What happens to the waste produced the higher the atom economy?
The higher the atom economy the less waste produced
How do you calculate the concentration of a solution?
Mass of a solute (g) / Volume of a solution (dm^3)
What can you use titrations to find?
To find the exact volume of acid and alkali that react together
What is the equation that links moles, concentration and volume?
Moles = concentration x volume
What is the volume occupied by 1 mole of any gas?
24dm^3
How do you calculate the number of moles of gas?
Volume of gas/24dm^3
