# Chemistry

posted by
**Kishwa** on
.

Urgent... Someone please help!!

Can someone please check to see if I am doing these correctly, I have a test tomorrow... Thank you :)

Q) Calculate the new molarity of a 35mL sample of 0.450 M CaCl2 solution that is diluted with enough water to make 250 mL of solution.

A) 0.450 m CaCl2 x 35mL/250mL = 0.063 mL diluted solution

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Q) Calculate the new molarity of a 35mL sample of 0.450 M CaCl2 solution that is diluted with enough water to make 250 mL of solution.

A) M1V1 = M2V2

M1 = 0.450

M2 = ?

V1 = 0.035 L

V2 = 0.250 L

M2 = M1 X V1/V2

0.450 X (0.035L/0.250L) = 0.063

Given: 450 mL (0.450L); 0.250 M KNO

Need: Mass of KNO

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Q) What mass of KNO3 (MW=101) is needed to prepare 450mL of 0.250 M KNO3 in water?

A) 0.450 L Solution x 0.250 M KNO/1 L solution x 101g KNO/1 mol KNO

= 11.4 g KNO