How many grammes of NaOH(s) would be needed to produce 100.0 cm3 of a 0.20
CHEMISTRY
WAEC 2023
How many grammes of NaOH(s) would be needed to produce 100.0 cm3 of a 0.20 mol dm-3 NaOH, (aq)? [NaOH = 40.0]
- A. 800.0g
- B. 0.02 g
- C. 20.0 g
- D. 0.80 g
Correct Answer: D. 0.80 g
Explanation
Amount (in moles) = Molarity × Volume
Amount (in moles) = 0.20 mol/dm³ × 100.0 cm³ / 1000 cm³/dm³ = 0.020 moles
Now, we can calculate the mass using the formula:
Mass = Amount × Molar Mass
Mass = 0.020 moles × 40.0 g/mol = 0.80 g
So, the correct answer is:0.80 g
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