Homework Help: Chemistry

Posted by Olivia on Tuesday, December 13, 2011 at 7:43pm.

A 1.42-g sample of a pure compound, with formula M2SO4, was dissolved in water and treated with an excess of aqueous calcium chloride, resulting in the precipitation of all the sulphate ions as calcium sulphate. The precipitate was collected, dried, and found to weigh 1.36 g. Determine the atomic mass of M, and identify M.

Please explain!

Chemistry - DrBob222, Tuesday, December 13, 2011 at 8:13pm
..........M2SO4 + CaCl2 --> CaSO4 + 2MCl
initial....1.42g....0........0........0
add................xs..........
change.......................1.36
equil......0..................1.36
moles CaSO4 = 136/molar mass CaSO4.
moles M2SO4 = moles CaSO4 (1 mole CaSO4 came from 1 mole M2SO4.)
moles M2SO4 = grams/molar mass. You know moles from above and grams from the problem, solve for molar mass.
Now that you know the molar mass of M2SO4, subtract 96 (due to the SO4) to leave 2 M^+, then divide by 2 to obtain M. You can look on the periodic table to identify M.

Answer this Question

Related Questions

ap chem - A 1.42 g. sample of a pure compound, with formula M2SO4, was ...
chemistry - A sample of 0.6760 g of an unknown compound containing barium ions (...
Chemistry - A 0.5370 g sample of a pure soluble chloride compound is dissolved ...
Chemistry 219 - An amount of 1.250g of an alloy (90% Ag, 10% Cu) was treated ...
chemistry - Heating a 2.00g sample of magnesium metal with an excess of pure ...
Chemistry - A 2.52g sample of a compound containing only carbon, hydrogen, ...
Gen. Chemistry - A 0.887 g sample of a mixture of NaCl and KCl is dissolved in ...
chemistry - In the course of research, a chemist isolates a new compound with an...
chemistry - A compound of Fe and Cl is soluble in water. An excess of AgNO3 was ...
College Chem - Impure sample of table salt that weighed 0.8421g, when dissolved ...

For Further Reading

First Name:
School Subject:
Answer: