Which of the following methods can be used to obtain pure water from a mixture of sand, water and methanoic acid?
Neutralization with NaOH followed by filtration
Neutralization with NaOH followed by distillation
Fractional distillation
Filtration followed by distillation
How many atoms are present in 6.0 g of magnesium? [Mg = 24, NA = 6.02 × 1023 mol−1]
1.20 × 1022
2.41 × 1022
1.51 × 1023
3.02 × 1023
50 cm³ of gas was collected over water at 10°C and 765 mmHg. Calculate the volume of the gas at s.t.p. if the saturated vapour pressure of water at 10°C is 5 mmHg.
49.19 cm³
48.87 cm³
48.55 cm³
48.23 cm³
An increase in the pressure exerted on gas at a constant temperature results in
a decrease in the number of effective collisions
a decrease in volume
an increase in the average intermolecular distance
an increase in volume
In the reaction 2H2(g) + O2(g) → 2H2O(g), what volume of hydrogen would be left over when 300 cm³ of oxygen and 1000 cm³ of hydrogen are exploded in a sealed tube?
200 cm³
400 cm³
600 cm³
700 cm³
