4.1 and 4.2 :Stoichiometry and moles Flashcards
What is relative atomic mass?
The average mass of naturally occurring atoms of an element where C is 12 units.
What is relative molecular mass and relative formula mass?
Relative molecular mass (Mr) is the sum of relative atomic masses in molecule. Ionic compounds use relative formula mass.
What are the state symbols used in an ionic equation?
s - solid
aq - aqueous (dissolved in water)
g - gas
l - liquid
What is a mole?
It is the amount of a substance.
What is Avogadro constant?
Number of units in one mole of any substance
Formula for percentage yield and percentage purity.
Percentage purity = (pure / impure) x 100
Percentage yield = (mass obtained / calculated mass) x 100
What is empirical formula?
Simplest ratio of atoms in a compound
e.g Molecular formula of ethanol = C2H5OH
Empirical formula of ethanol = C2H6O
What is the formula for molar mass?
molar mass = mass / number of moles
/ \
/ \
/ mass \
/\_\_\_\_\_\_\_\
/ | \
/ Nb | Molar \
/ moles | mass \
/\_\_\_\_\_\_|\_\_\_\_\_\_\
What is formula for volume of moles?
volume = nb moles / 24 dm^3
/ \
/ \
/volume\
/\_\_\_\_\_\_\_\
/ | \
/ Nb | 24 \
/ moles | dm^ 3\
/\_\_\_\_\_\_|\_\_\_\_\_\_\
What is the formula for concentration?
concentration = nb. moles / volume
/ \
/ Nb \
/ moles \
/\_\_\_\_\_\_\_\_\_\
/ | \
/ Vol- | Conce- \
/ -ume | -ntration \
/\_\_\_\_\_\_|\_\_\_\_\_\_\_\_\
What does an element + oxygen give?
element oxide
What does a metal + acid give?
salt + hydrogen
What does an acid + base give?
salt + water
What does an acid + carbonate give?
salt + water + carbon dioxide
What does a non-metal + water give?
acid
