CHEMISTRY CALCULATION - STOICHIOMETRY. ''LIKE 2023 UTME QUESTIONS''

 1. At the same temperature and pressure, 50 cm3 of nitrogen gas contains the same number of molecules as?

A 25 cm3 of methane.

B 40 cm3 of hydrogen

C 50 cm3 of ammonia

D 100 cm3 of chlorine

2. How many moles are there in 30g of CaCO3?

[Ca = 40, C = 12 , O = 16]

A 0.50

B 1.00

C 0.30

D 0.20

3. 150cm3 of hydrogen are sparked with 50cm3 of oxygen at 100°C and 1atm. The total volume of the residual gases is

A 150cm3

B 200cm3

C 100cm3

D 50cm3

4. What volume of 0.25moldm-3 Na2CO3 solution would give 13.25g Na2CO3 on evaporation to dryness? [Na2CO3 = 106gmol-1]

A 250cm3

B 500cm3

C 750cm3

D 1,250cm3

5. Consider the reaction: 2Al(s) + 6H+(aq) → 2Al3+(aq) + 3H2(g). What is the total number of moles of electrons transferred from the aluminium atoms to the hydrogen ions?

A 3

B 4

C 5

D 6

6. What mass of Sulphur (IV) oxide is produced when 24.0g or Sulphur react with 16g of oxygen?

(S = 32, O = 16)

A 8.0g

B 16.0g

C 24.0g

D 32.0g

7.1.0g of limestone was treated with excess 0.5 moldm-3 H2SO4. The acid left at the end of reaction required 30cm3 of 0.025moldm-3 NaOH for complete neutralization. What is the original volume of acid?

A 57cm3

B 21cm3

C 33cm3

D 68cm3

8. What volume of 0.25moldm-3 Hydrochloric acid would be required to dissolve 0.48g of magnesium completely? [My = 24.0]

A 160cm3

B 200cm3

C 240cm3

D 320cm3

9. Calculate the solubility of 10.1g of potassium trioxonitrate(V) dissolved in 50g of distilled water at 25oC [K = 39, N = 14, O = 16]

A 10.0 moldm-3

B 5.0 moldm-3

C 0.1 moldm-3

D 2.0 moldm-3

10. If 20cm3 of Distilled water is added to 80cm3 of 0.50 mol dm-3 hydrochloric acid, the new concentration of the acid will be

A 0.10 moldm-3

B 0.20 moldm-3

C 0.4 moldm3

D 2.00 moldm-3

11. How many atoms are there in one mole of hydrogen gas?

[Avogadro's constant = 6.02 × 1023 mol-1]

A 1.2 × 1023

B 6.0 × 1023

C 12 × 1024

D 60 × 1024

12. A gas occupies a volume of 250cm3 at 27°C and 0.6atm its volume at s.t.p is ......

A 137cm3

B 169cm3

C 416cm3

D 150cm3

13. What mass of Sulphur (IV) oxide is produced when 24.0g or Sulphur react with 16g of oxygen?

(S = 32, O = 16)

A 8.0g

B 16.0g

C 24.0g

D 32.0g

14. 1050cm3 of helium gas was produced at -330C and 700 mmHg. What volume would the gas occupy at 230 and 750mmHg?

A 1,208.7cm3

B 794.59cm3

C 912.16cm3

D 1387.50cm3

15. What is the concentration of a solution containing 2g of NaOH in 100cm3 of solution?

[Na = 23, O = 16, H = 1]

A 0.40 mol dm-3

B 0.50 mol dm-3

C 0.05 mol dm-3

D 0.30 mol dm-3

16. For the given unbalanced reaction CaSO4 + NaCl → CaCl2 + Na2SO4
1. How many CaSO4 in kg is required for producing 1 mole of Na2SO4? Assume NaCl in excess.
A. 136 kg
B. 156 kg
C. 176 kg
D. 196 kg

17. How many kg of Na2SO4 will be produced using 80 kg of NaCl? Assume CaSO4 in excess.

A. 122 kg
B. 142 kg
C. 162 kg
D. 182 kg

18. How many moles of CaCl2 will be produced using 300 kg of CaSO4? Assume NaCl in excess.

a) 2.2 kg
b) 4.2 kg
c) 6.2 kg
d) 8.2 kg