Molarity plz help me

Question

1. How many moles in 4.2L of a 1.5M solution?

2. How many grams of NaCl in 1.0L of a 3.5M solution of NaCl?

3. What is volume of a 1.5M solution that contains 88g Na2CO3?

4. What is molarity of 2.3L of a solution containing 5 moles of a solute?

5. What volume of 0.25M solution contains 2.3 moles of solute?

6. If 17g CCl4 is dissolved in 850mL, what is M?

7. 84g CH3COOH is used to prepare a 2M solution, what is the volume?

8. What is mass of Ca(OH)2 in 1.0L of a 2.5M solution?

9. What mass of LiOH is present in a 3.8M solution occupying 250mL?

10. What mass of H2SO4 must be used to produce 6L at 3.2M

Answer 1

Molarity (M) = moles / liter

Won't do all but will guide you. You should be able to do these yourself, and Wyzant frowns on tutors doing homework for students. You should become very, very familiar with using DIMENSIONAL ANALYSIS. If you don't know this, you MUST learn it. It will save you in chemistry.

(1). 4.2 L x 1.5 mol / L = 6.3 moles (uses dimensional analysis)

(2). molar mass NaCl = 58 g / mol

1.0 L x 3.5 mol / L = 3.5 mols NaCl x 58 g / mol = 203 g NaCl (uses dimensional analysis)

(3). molar mass Na2CO3 = 106 g / mol

88 g Na2CO3 x 1 mol / 106 g = 0.830 mols Na2CO3

0.830 mols / x L = 1.5 mol/L

x = 0.553 L = 533 mls

(9). molar mass LiOH = 23.9 g / mol

3.8 mol / L x 0.250 L = 0.95 mols (dimensional analysis)

0.95 mols x 23.9 g / mol = 22.7 g = 23 g (dimensional analysis)

(10). molar mass H2SO4 = 98 g / mol

6 L x 3.2 mol / L x 98 g / mol = 1882 g H2SO4 = (dimensional analysis)