Question

1. you want to prepare 1L of a solution containing 1.00ppm Fe2+. How many grams ferrous ammonium sulfate must be dissolved and diluted in 1L? What would be the molarity of this solution?

2.how many grams NaCl should be weighed out to prepare 1 L of a 100ppm solution of (a)Na+ (b) cl-

3.you have a 250 ppm solution of k+ as kcl. you wish to prepare from this a 0.00100M solution of Cl-. how many mililiters must be diluted to 1 L?

4.you are required to prepare working standard solutions of 1.00x10^-5, 2.00x10^-5, 5.00x10^-5,and 1.00x10^-4M glucose from a 0.100M stock solution. you have available 100ml flask and pipets of 1.0,2.0,5.0, and 10.0ml. How to prepare the working standards?

Answer 1

The density of water is 1.0 g.ml-1, so the mass of water is 1000gm. At such ilue levels, the mass of FAS is negligible compared to the mass of the solvent, so the mass of the soluion is alo 1000g. Use he concentration of 1.0ppm to convert the totals to the mass of Fe ion present

B) First conversion factor

Molecular weight for NaCl = 58 g/mol

Atomic weight for Na = 23 g/mol

Each 58 g of NaCl contain 23 g of Na by convert grams to milligrams

Each 58 mg of NaCl contain 23 mg of Na

C)

molarity of the 250 ppm KCl soultion

1 ppm = 1 mg/Kg or 1 mg/L

so what is 250 ppm 250 mg/L

so convert that to molarity 1 g = 10^3 mg..or 10-3 g /1 mg...so .250 g/lL

you need to find the Molarity

that is the molarity of your concentrated solution

Now using M1V1 = M2V2 to get your other