SC9 Calculations involving Masses Flashcards
1
Q
Define empirical formula
A
tells you the smallest whole number ratio of atoms in the compound (use Mr Cook’s method)
2
Q
Define molecular formula
A
Molecular formula is the actual number of atoms of each element in a compound
3
Q
Law of conservation of mass in a closed system
A
The total mass of the system before and after doesn’t change.
4
Q
Law of conservation of mass in a non-enclosed system
A
The total mass may change
- If mass increases, it’s because one of the reactants is a gas found in air
- If mass decreases, it’s because some or all of the reactants are solids, liquids, aqueous, and one of the products is a gas
5
Q
Define mole of particles
A
One mole of atoms or molecules of any substance will have a mass in grams equal to the relative particle mass (Ar or Mr) for that substance
6
Q
Why is the mass of a product formed controlled by the mass of a reactant that is not in excess?
A
Only so much product can be formed if there is only so many reactants to make the product
