Flashcards in Unit 3-Quantitative chemistry Deck (23):
How do you calculate the percentage mass of an element in a compound?
=Ar x number of atoms of that element divided by the Mr of the compound x 100
What is the relative atomic mass the same as?
The mass number.
How do you work out the number of moles?
=mass (g) divided by the Mr
During a chemical reaction can atoms be created or destroyed?
Why may mass increase in a reaction?
If gas is involved it cannot account for the gas in the air before hand, so when it reacts with a gas mass can be gained.
Why might mass decrease in a reaction?
Some gas in the reaction could escape during the reaction.
What is the reactant that’s used up in a reaction called?
The limiting reactant.
The amount of product formed is ? to the limiting reactant.
Why is the limiting reactant directly proportional to the amount of product formed?
If you add more reactant there will be more reactant particles to take part in the reaction which means more product particles.
How do you work out the volume of a gas?
Volume of gas=mass of gas divided by Mr of gas x24
How do you work out concentration with the mass of solute?
Concentration= mass of solute divided by volume of solvent.
How do you work out concentration with the number of moles of solute?
Concentration= number of moles of solute divided by volume of solvent.
What is one tonne equal to?
What is 1 kg equal to?
What is 1 mg equal to?
What does excess mean in chemistry?
When the amount of the reactant is greater than the amount of the amount that can react.
The higher the atom economy of a reaction...
The less waste produced.
What is volume measured in?
How do you work out volume?
24 x moles.
What does 1dm cubed equal?
1000 cm cubed.
What is a pipette?
A glass tube with a tap and scale for measuring liquids to the nearest 0.1cm cubed.
What is meant by the end point?
The moment when the indicator changes colour in a titration.