C3: Quantitative Chemistry Flashcards
What is a relative atomic mass?
All of the atoms in a molecular formula added together
How do you calculate the Mr?
Add up the atoms given in the question.
How do you calculate the % mass of an element in a compound?
Ar/ Mr x100
What is Mr?
Relative formula mass
What is Ar?
Relative atomic mass
What is a mole?
The name given to an amount of a substance
What is avogadro’s constant?
6.02 x 10*23
How are moles and avogadro number linked?
One mole is an amount of a substance that contains avogadro’s constant amount of particles.
What is the formula for finding moles?
Mass= Mr Moles
What is the conservation of mass?
Mass cannot be created or destroyed
How are the conservation of mass and reaction equation linked?
The mass of the reactants and the products are equal.
What are the two explanations for change in mass in a reaction?
One of the products are gas and it was released in the surroundings or one of the reactants was a gas and reacted with a solid or a liquid
How do you calculate masses in reaction?
Moles= mass/ Mr
What do the numbers in front of a chemical formula mean?
How many moles of each substance are needed in each equation
Why do reactions stop?
One of the reactants have been used up.
What happens to the other reactions when one is used up?
They are left in excess
What is the reactant that is used up called?
Limiting reactant
How do you calculate the mass of product formed in a reaction?
- write out the balanced the equation
- work out the Mr of the reactant and product
- find out how many moles are in each
