[dafolk]

1.Describe the preparation of 600 mL of 1.00M HNO3 (63.0 g/mol) from the commercial reagent that is 71% HNO3 (w/w) and has a specific gravity of 1.43.
I had 1.143g/ mL * 71% * 100 mL/L making it a 12.88 M reagent, then 1mol/12.88 M * 600 mL = 46.6 mL HNO3

2. What mass of solid PbCl2 (278.1 g/mol) is formed when 200.0 mL of 0.125 M Pb2+ is mixed with 400.00 mL of 0.175 M Cl-
I ended up with 20.9 g PbCl2 but really not sure how to work the problem

3. What is the molarity of Cl- in a solution that contains 121.3 ppm of MgCl2 (95.2104 g/mol)? (Assume the density of the solution to be 1.000g/mL)
I had 121.3 mg/L * 1L/1000mL = 0.1213 g/L then 1 mol/95.2104g = 1.27 x 10-3 M

These are the three problems I got wrong and I would love your guys help
Thanks much!

[voidSetup]

For number 3 you've calculated the molarity of MgCl₂ in the solution but there are two Cl^- ions per MgCl₂.

[dafolk]

so just double my result and it should be correct?

[voidSetup]

Yep. For number 2 do you assume PbCl₂ is not soluble at all or do you need the K_sp?

[dafolk]

im guessing you assume it isnt since the Ksp is not provided

[AWK]

1.

has a specific gravity of 1.43

I had 1.143g/ mL * 71% * 100 mL/L

molar concentations - moles in 1000 ml

2. Take into account which is a limiting reagent!

[dafolk]

shoot i actually had 1000 mL but mistyped 100, sorry

also since the specific gravity is 1.43 does it make it 1.143 g/mL or 1.43 g/mL?

[dafolk]

also i number two i had .025 moles of Pb added to .05 moles of Cl so I am pretty sure I had the limiting reagent, but do those added up make it .075 moles of PbCl2 or just .025 moles?

[AWK]

1.143 g/mL or 1.43 g/mL

Which one is mistyped?

_{had .025 moles of Pb added to .05 moles of Cl}
this is a stoichiometry.
How many moles of Cl^- you have?
Which element (ion) is in excess. What does mean?