Gravimetric determinination.Answer the following to determine the soluable sulfate content of a solid sample by precipitation of insoluable BaSO4 a) How do you calculate the volume of 10% (wt/v) barium chloride solution needed to completely precipitate SO4^2-? Assuming the unknown soluble sulfate is Na2SO4 b) Use these conventions to show the calculations necessary to determine the mass (in mg) of sulfate per gram of unknown solid sample. Mass of unknown sample (g): Use the variable "a" to represent this value Mass of BaSO4 (g): Use the variable "b" to represent this value

Expert Answers

| Certified Educator

We can write the equation of the reactions to be:

BaCl2 + Na2SO4 ---> BaSO4 + 2NaCl

The mass of the unknown soluble sulphate should be given in order to solve for the volume of the BaCl2 solution. The procedure for the determination of the volume of BaCl2 solution is as follows:

1. From the mass of the Na2SO4, we can solve for the moles Na2SO4 using the molar mass of Na2SO4.

2. From the balanced equation, we can see that the ration of Na2SO4 and BaCl2 is 1:1 therefore: moles Na2SO4 = moles BaCl2

3. Next, we convert the moles of BaCl2 to mass BaCl2 using the molar mass of BaCl2. The mass of BaCl2 calculated is the weight of BaCl2 in the solution. Meaning it is the 10%wt of the unknown volume.

4. From the mass of the BaCl2, we can now solve for the volume of the solution.

Wt% = mass BaCl2/mL solution

mL solution = (10/100) x ( mass BaCl2)

**please provide the value of the mass of the Na2SO4 to solve the problem.

See eNotes Ad-Free

Start your 48-hour free trial to get access to more than 30,000 additional guides and more than 350,000 Homework Help questions answered by our experts.

Get 48 Hours Free Access

Already a member? Log in here.

Approved by eNotes Editorial Team