C4 - Quantitative Chemistry
- Created by: JellyBeanBears
- Created on: 15-05-18 20:11
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- Quantitative Chemistry
- The Mole
- the name given to the amount of a substance
- Avogadro's constant = 6.02 x 10'23
- Moles = mass (g) / Mr
- the mole of an atom or compound is the RAM in grams
- Limiting Reactants
- reactants that get used up first and cause the reaction to stop
- the amount of the product depends on the limiting reactant
- the mass of a product can be calculated by using the mass of a limiting reactant and the balanced symbol equation
- 1) write balanced equation
- 2) work out Mr of the reactant and product you want
- 3) work out moles
- 4) use the number of moles to fin the mass
- 3) work out moles
- 2) work out Mr of the reactant and product you want
- 1) write balanced equation
- Relative Formula Mass
- Compounds have a relative formula mass (RAM / Mr)
- It is the sum of all atomic masses of the atoms in the compound
- %mass of an element in a compound= (At x no atoms in element / Mr of compound ) x100
- The Mole and Equations
- moles can be used to calculate the mass in reactions
- mass= moles x Mr
- the big numbers in symbol equation tell you the amount of moles for each reactant and product
- if there is not a big number then the mole is 1
- if you have the masses of the reactants and products you can work out the balanced symbol equation
- 1) mass/RAM for each substance to find moles
- 2) Mole / smallest mole in reaction
- 3) make them all whole numbers if any are decimals
- 4) write out the balanced equation using the whole numbers neatly
- 3) make them all whole numbers if any are decimals
- 2) Mole / smallest mole in reaction
- 1) mass/RAM for each substance to find moles
- Conservation of Mass
- in a closed chemical reaction the mass of the products is equal to the mass of the reactants
- atoms cannot be created or destroyed
- this is the reason we balance equations
- if the mass changes in an open chemical reaction a gas is usually release, causing it to seem like the mass has decreased or increased
- Concentration of solutions
- concentration = mass of solute (g) / volume of solvent (dm3)
- it is a measure of how crowded thing are
- The Mole
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