4. 1 mole of HCl will neutralise:
a) 5dm 3 of 0.2mol /dm 3 KOH (aq). True or false?
MV IGCSE Calculations wk5 ws1
b) 2dm 3 of 0.2 mol /dm 3 NaOH (aq). True or false?
c) 2dm 3 of 0.5 mol /dm 3 KOH (aq). True or false?
d) 0.5dm 3 of 1 mol /dm 3 KOH (aq). True or false?
e) 250 cm 3 of 2 mol /dm 3 Na 2 CO 3 (aq). True or false?
f) 200 cm 3 of 4 mol /dm 3 Na 2 CO 3 (aq). True or false?
CHEMISTRY CONCENTRATION NEUTRALISATION?
2019-03-06 6:58 pm
回答 (1)
2019-03-06 11:37 pm
4.
a)
HCl + KOH → KCl + H₂O
No. of moles of KOH = (0.2 mol/dm³) × (5 dm³) = 1 mol
Mole ratio HCl : KOH = 1 : 1
This fits the mole ratio indicated by the equation.
Hence, it is true.
b)
HCl + NaOH → NaCl + H₂O
No. of moles of NaOH = (0.2 mol/dm³) × (2 dm³) = 0.4 mol
Mole ratio HCl : NaOH = 1 : 0.4
This does not fit the mole ratio indicated by the equation.
Hence, it is false.
c)
HCl + KOH → KCl + H₂O
No. of moles of KOH = (0.5 mol/dm³) × (2 dm³) = 1 mol
Mole ratio HCl : KOH = 1 : 1
This fits the mole ratio indicated by the equation.
Hence, it is true.
d)
HCl + KOH → KCl + H₂O
No. of moles of KOH = (1 mol/dm³) × (0.5 dm³) = 0.5 mol
Mole ratio HCl : KOH = 1 : 0.5
This does not fit the mole ratio indicated by the equation.
Hence, it is false.
e)
2HCl + Na₂CO₃ → 2NaCl + H₂O + CO₂
No. of moles of Na₂CO₃ = (2 mol/dm³) × (250/1000 dm³) = 0.5 mol
Mole ratio HCl : Na₂CO₃ = 1 : 0.5 = 2 : 1
This fits the mole ratio indicated by the equation.
Hence, it is true.
f)
2HCl + Na₂CO₃ → 2NaCl + H₂O + CO₂
No. of moles of Na₂CO₃ = (4 mol/dm³) × (200/1000 dm³) = 0.8 mol
Mole ratio HCl : Na₂CO₃ = 1 : 0.8 = 2 : 1.6
This does not fit the mole ratio indicated by the equation.
Hence, it is false.
a)
HCl + KOH → KCl + H₂O
No. of moles of KOH = (0.2 mol/dm³) × (5 dm³) = 1 mol
Mole ratio HCl : KOH = 1 : 1
This fits the mole ratio indicated by the equation.
Hence, it is true.
b)
HCl + NaOH → NaCl + H₂O
No. of moles of NaOH = (0.2 mol/dm³) × (2 dm³) = 0.4 mol
Mole ratio HCl : NaOH = 1 : 0.4
This does not fit the mole ratio indicated by the equation.
Hence, it is false.
c)
HCl + KOH → KCl + H₂O
No. of moles of KOH = (0.5 mol/dm³) × (2 dm³) = 1 mol
Mole ratio HCl : KOH = 1 : 1
This fits the mole ratio indicated by the equation.
Hence, it is true.
d)
HCl + KOH → KCl + H₂O
No. of moles of KOH = (1 mol/dm³) × (0.5 dm³) = 0.5 mol
Mole ratio HCl : KOH = 1 : 0.5
This does not fit the mole ratio indicated by the equation.
Hence, it is false.
e)
2HCl + Na₂CO₃ → 2NaCl + H₂O + CO₂
No. of moles of Na₂CO₃ = (2 mol/dm³) × (250/1000 dm³) = 0.5 mol
Mole ratio HCl : Na₂CO₃ = 1 : 0.5 = 2 : 1
This fits the mole ratio indicated by the equation.
Hence, it is true.
f)
2HCl + Na₂CO₃ → 2NaCl + H₂O + CO₂
No. of moles of Na₂CO₃ = (4 mol/dm³) × (200/1000 dm³) = 0.8 mol
Mole ratio HCl : Na₂CO₃ = 1 : 0.8 = 2 : 1.6
This does not fit the mole ratio indicated by the equation.
Hence, it is false.
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