1. 3.2g of sivler nitrate was added to 50cm3 of 0.4mol/dm3 of
calcium chloride. calculate the mass of silver chloride
precipitated at the end of experiment.
The equation of reaction: 2AgNO3 + CaCl2 -> 2 AgCl +
Ca(NO3)2
Mr of AgNO3 = 170
No of moles of AgNO3 = 3.2/170 = 0.01882352941 moles
50cm3 of CaCl2 = 0.05dm3
Concentration in mol/dm3 = no of moles of CaCl2 / vol. of
soln.
0.4 = no of moles of CaCl2 / 0.05
.: no of moles = 0.4 *0.05 = 0.02 moles
Limiting factor is silver nitrate.
Compare silver nitrate with silver chloride. (in terms of mole
ratio)
no of moles needed for Agcl = 0.1882352941 moles
Find Mr of AgCl = 143.5
Mass of AgCl: 143.5 *0.018823352941
= 2.70g
2. Aqueous barium chloride reacts with sulphuric acid according
to equation below
BaCl2 + H2SO4 -> BaSO4 + 2HCl
a. calculate the mass of baiurm sulphate precipitate produced
when 250cm3 of 0.2mol/dm3 of sulphuric acid reacts with 200cm3 of
0.25mol/dm3 of barium chloride.
Answer's too lengthy and I don't have much time to spare... so
i'll just show part of the answer.
In this question, there's no limiting factor as no. of moles for
the reactants are exactly the same.
The answer I got is 11.65g
3rd question.
zinc reacts with silver ions according to the equation : Zn +
2Ag+ ->Zn2+ + 2 Ag.
calculate mass of zincions formed when 0.4mol of zinc atoms are
added to 5cm3 of 0.6mol/dm3 of silver ions.
limiting factor is Ag+ for this case.
Mole ratio for Ag+ : Zn2+
2 : 1
= 0.009 : 0.0045
Last part: is Mr of Zn2+ same as zinc atoms 65? if thats the
case, then
0.0045 = mass of zn2+ / 65
mass = 65 *0.0045
=2.925g
Help me check the following questions. but they should be
correct, as far as i know. find limiting factor for each case.
1. calcium hydroxide : 7.5g/dm3 and 20 cm3
Nitric acid : 0.81mol/dm3 and 25cm3
limiting factor is calcium hydroxide (ans)
2. Potassium hydroxide: 12g/dm3 and 32cm3
Ammomium sulphate - 2.9g
limiting factor is potassium hydroxide(ans)
3. calcium metal - 6g
sulphuric acid : 0.8mol in 500cm3
calcium has 0.15moles and suplhuric acid 0.8moles.
limiting factor is calcium. (ans)
for the last 3 questions, please try to work out the statements
on your own because i'm in a rush for time. sorry... and
thanks!