Chemistry
10 g. of a mixture of NaCl and anhydrous Na2SO4 is dissolved in water. An excess of BaCl2 soln. is added and 6.99 g. of BaSO4 is precipitated according to the equation :
Na2SO4 + BaCl2 → BaSO4↓ + 2NaCl.
Calculate the percentage of Na2SO4 in the original mixture.
[O = 16 ; Na = 23 ; S = 32; Ba = 137]
Related Questions
Na2SO4 + Pb(NO3)2 ⟶ PbSO4 + 2NaNO3. When excess lead nitrate solution was added to a solution of sodium sulphate, 15.15 g of lead sulphate were precipitated. What mass of sodium sulphate was present in the original solution.
[H = 1 ; C = 12 ; O = 16 ; Na = 23; S = 32 ; Pb = 207]
From the equation : (NH4)2 Cr2O7 ⟶ Cr2O3 + 4H2O + N2 Calculate :
(i) the vol. of nitrogen at STP, evolved when 63 g. of ammonium dichromate is heated.
(ii) the mass of Cr2O3 formed at the same time.
[N = 14, H = 1, Cr = 52, O = 16]
The reaction of potassium permanganate with acidified iron (II) sulphate is given below :
2KMnO4 + 10FeSO4 + 8H2SO4 ⟶ K2SO4 + 2MnSO4 + 5 Fe2(SO4)3 + 8H2O.
If 15.8 g. of potassium permanganate was used in the reaction, calculate the mass of iron (II) sulphate used in the above reaction.
[K = 39, Mn = 55, Fe = 56, S = 32, O = 16]
The equations given below relate to the manufacture of sodium carbonate [Mol. wt. of Na2CO3 = 106]
(i) NaCl + NH3 + CO2 + H2O ⟶ NaHCO3 + NH4Cl
(ii) 2NaHCO3 ⟶ Na2CO3 + H2O + CO2
Questions (a) and (b) are based on the production of 21.2 g. of sodium carbonate.
(a) What mass of sodium hydrogen carbonate must be heated to give 21.2 g. of sodium carbonate [Molecular weight of NaHCO3 = 84].
(b) To produce the mass of sodium hydrogen carbonate calculated in (a), what volume of carbon dioxide, measured at s.t.p., would be required.