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1.†††††† In 100 mL of a solution, there are 3.0 g of NaCl.† Find the molarity.

3.0 g NaCl (mole/58.5 g) = 0.05128205128 mole NaCl

n = CV

0.05128205128 mole = C(0.100 L)

C = 0.05128205128 mole/(0.100 L) = 0.51 moles/L

2.†††††† In 2.0 L of a solution, there are 3.0 g of KF.† Find the molarity.

3.0 g of KF(mole/58 g)= 0.05172413793 mole KF

n = CV

0.05172413793 mole = C(2.0 L)

C = 0.05172413793 mole/2.0 L

= 0.026 moles/L

3.†††††† How many grams of KBr are needed to prepare 2.5 L of a 0.25 mole/L solution?

n = CV

= 0.25 mole/L (2.5 L)

= 0.625 moles KBr

0.6258 moles KBr *(39.1+79.90)g/mole = 75 g†††† (74.5)

4.†††††† How many grams of Ca(ClO)2 are needed to prepare 2.0 L of a 0.45 mole/L

††††††††† solution?

n = CV

= 0.45 mole/L (2.0 L)

= 0.90 moles Ca(ClO)2

0.90 moles Ca(ClO)2 (142.98 g/mole) = 128.682 g

5.†††††† What is the volume of a solution containing 3.0 grams of HNO3 if the concentration is 0.10 †††††† mole/L.

n = CV

First need n:

3.0 g HNO3 (mole/(1+14+48)) = 3/63 = 0.04761904762† moles HNO3

n = CV

0.04761904762† moles HNO3 = (0.10 mole/L)V

V = 0.04761904762† moles HNO3/† 0.10 mole/L = 0.48 L

6.               Explain how you would actually prepare 3.0 L of a 0.2 mole/L Na Br solution in the lab.

n = CV

= 0.2 mole/L Na Br(3.0 L)

=0.6 moles Na Br

0.6 moles Na Br (102.89g/mole)

= 61.7 g

Weigh 61.7 g

Dissolve in < 3.0 L in a beaker

Transfer to a 3.0 Lvolumetric flask

Add water to white line and mix

Donít forget the rest of the homework