What is meant by the relative atomic mass of an element (also represented as the symbol Ar)?
It is the mass of an atom of a particular element measured in grams
It is the actual mass of an atom of an element compared to the mass of a molecule of the element
It is the average mass of the atoms of an element compared to the mass of an atom of carbon-12
What is the relative atomic mass (Ar) of aluminium? Use the periodic table to help you.
13
14
27
What is the relative formula mass (Mr) of magnesium oxide (formula MgO)? Use the periodic table to help you.
40
30
20
What is the relative formula mass (Mr) for sulfuric acid (formula H2SO4)? Use the periodic table to help you.
50
98
49
What is the empirical formula for hydrogen peroxide which has a molecular formula of H2O2?
HO
H2O2
H2O
The empirical formula for a compound is CH2 and its relative atomic mass (Ar) is 70. What is its molecular formula? Use the periodic table to help you.
CH2
C5H10
C70H140
If 2.8 g of nitrogen combines with 6.4 g of oxygen, what is the empirical formula of the nitrogen oxide formed? Use the periodic table to help you.
NO
N2O
NO2
What does the law of conservation of mass state?
That the total mass of the reactants will always be the same as the total mass of the products
That the total mass of the reactants will always be more than the total mass of the products
That the total mass of the reactants will always be less than the total mass of the products
What mass of cobalt must have reacted if 3.20 g of oxygen forms 7.92 g of cobalt oxide?
3.20 g
4.72 g
7.92 g
What is the concentration of a solution formed by dissolving 4 g of potassium hydroxide in 200 cm3 of water?
0.05 g /cm3
0.02 g/dm3
20 g/dm3