# Science : Chemistry

posted by .

The concentration of dissolved chlorine in tap water can be determined by adding excess potassium iodide and then using aqueous sodium thiosulphate to precipitate the resulting iodide ions. In Ontario, the aesthetic objective for chlorine in tap water is a maximum concentration of 250 mg/L. Find the minimum volume of a 0.00100 mol/L solution of potassium iodide that should be used to test a 500mL sample of water.

• Science : Chemistry -

i would be great to show me the answer , but do it step by step so i understand better

• Science : Chemistry -

I don't know all of the details of the procedure you use but here are the steps you need.
Cl2 + 2I^- ==> I2 + 2Cl^-

So 500 mL sample x 250 mg/L means you have 250 mg/L x 0.500 L = 125 mg Cl2 present. How many moles is that?
0.125g/molar mass Cl2 = about 0.002.
Adjust for the volume of sample you will use. Surely you won't use all 500 mL.
Then moles KI soln required is twice moles Cl2 you have in the volume taken for analysis and L KI = moles KI/M KI. Solve for L and convert to mL.

• Science : Chemistry -

How many grams of H2 would be formed if 34 grams of carbon reacted with an unlimited amount of H2O? The reaction is:

C + H2O → CO + H2

The atomic mass of C is 12.01 g/mole. The atomic mass of H2 is 2.016 g/mole

## Similar Questions

1. ### Chemistry

Iron metal is dissolved in dilute aqueous HCl. The resulting solution is warmed with dilute nitric acid and then treated with aqueous potassium iodide. Write equations for the reactions. Ok so for the first step I got: Fe + 2HCl --> …
2. ### Chemistry-iodometric titration

In an iodometric titration, excess potassium iodide solution (KI) is added to the sample.Analyte such as chlorine liberates iodine from KI under acidic condition. Liberated iodine is titrated against standard sodium thiosulphate. The …
3. ### chemistry

the word equation for sodium and water is: sodium+water-->sodium hydroxide+hydrogen sodium and chlorine: sodium+chlorine-->sodium chloride what will the equation for aqueous chlorine with aqueous potassium iodide be?
4. ### chemistry

Aqueous silver nitrate reacts with aqeous potassium iodide in a double-replacement reaction to produce a precipitate of silver iodide. If 34.6 ml of 0.563 M silver nitrate are used with 148.4 ml of potassium iodide: a) What molarity …
5. ### Chem Hmwrk

Iodine can be prepared by bubbling chlorine gas through an aqueous solution of sodium iodide: 2NaI(aq) + Cl2(g) → I2(s) + 2NaCl(aq) How many grams of sodium iodide are required to produce 98 g of iodine?
6. ### chemistry

Determine the mass of the precipitate, lead iodide that is formed when 150 ml of 0.0500M pb(no3)2 is reacted with excess potassium iodide. if 3.3 of the precipitate is experimentally recovered, determine the percent yeild.
7. ### Chemistry

The concentration of barium ions in any solution can also be determined via gravimetric analysis. An impure sample of barium nitrate with a mass of 1.234 g, is completely dissolved in water and the resulting solution is reacted with …
8. ### Chemistry

The concentration of barium ions in any solution can also be determined via gravimetric analysis. An impure sample of barium nitrate with a mass of 1.234 g, is completely dissolved in water and the resulting solution is reacted with …
9. ### Chemistry

We can precipitate out solid lead(II) iodide from an aqueous lead(II) nitrate solution by adding potassium iodide. If we have 500. mL of 0.632 M lead(II) nitrate solution and add excess potassium iodide, how much solid lead(II) iodide …
10. ### Chemistry

I'm sorry here is another I do not understand. How do you find out exactly how much of a solution you would need to completely precipitate another compound in the reaction?

More Similar Questions