Astudent dissolved 4.00 g of co(no3)2 in enough water to make 100. ml of stock solution. he took 4.00 ml of the stock solution and then diluted it with water to give 275. ml of a final solution. how many grams of no3- ion are there in the final solution?

0.08097 grams of nitrate ions are there in the final solution.

Explanation:

Moles of cobalt(II) nitrate ,n=

Volume of the cobalt(II) nitrate solution, V = 100.0 mL = 0.1 L

Let the molarity of the solution be

A students then takes 4 .00 mL of solution and dilute it to 275 ml.

(molarity after dilution)

(after dilution)

Molarity of the of solution after dilution is 0.002375 M.

1 mol of cobalt(II) nitrate gives 2 moles of nitrate ions. Then 0.002375 M solution of cobalt (II) nitrate will give:

Moles of nitrate ions = n

Volume of the solution = 275 mL = 0.275 L

Molarity of the nitrate ions =

n = 0.001306 mol

Mass of 0.001306 moles of nitrate ions:

0.001306 mol × 62 g/mol= 0.08097 g

0.08097  grams of nitrate ions are there in the final solution.