Chemical Calculations With Mass Flashcards
What is the conservation of mass?
in a chemical reaction, atoms are not created or destroyed, just rearranged, so total mass before = total mass after the reaction
When a metal forms a metal oxide, why does the mass increase?
atoms from gaseous oxygen have been added
When an acid reacts with a metal, why does the mass decrease?
a gas is produced and escapes
What is relative formula mass?
the sum of the relative atomic masses of each atom in a substance
What are the four state symbols and what do they stand for?
(s) solid, (l) liquid, (g) gas, (aq) aqueous or dissolved in water
How can you tell when a symbol equation is balanced?
the number of atoms of each element is the same on both sides
What is a mole?
mass of a substance that contains 6.02 x 10^23 particles
Give the value for Avogadro’s constant
6.02 x 10^23
Which formula is used to calculate the number of moles from mass and Mr?
moles = mass/Mr
Which formula is used to calculate the mass of a substance from the number of moles and Mr?
mass = moles x Mr
What is a limiting reactant?
the reactant that is completely used up in a chemical reaction
What is a unit for concentration?
g/dm^3 or mol/dm^3
Which formula is used to calculate concentration from mass and volume?
concentration = mass/volume
Which formula is used to calculate volume from concentration and mass?
volume = mass/concentration
Which formula is used to calculate mass from concentration and volume?
mass = concentration x volume
