Answer to Question #327280 in General Chemistry for Anne

Question

1. Consider a solution prepared by adding 2.70 g of acetic acid(𝐶𝐻₃𝐶𝑂₂𝐻), to 122.8 g of water.

a. What is the percent by mass concentration of acetic acid in this solution?

b. What mass of acetic acid is present in 25.0g of this solution?

2. To prepare a solution, we dissolve 205 mL of ethanol in sufficient water to give a total volume of 235mL. What is the percent-by-volume concentration of ethanol?

3. What is the concentration in ppm of selenium if 0.020g is found in 5.0 × 10³𝑘𝑔 of soil?

4. A solution contains 117g of potassium hydroxide (KOH), dissolved in sufficient water to give a total volume of 2.00 L. The molar mass of KOH is 56.11 𝑔/𝑚𝑜𝑙 . What is the molarity of the aqueous potassium hydroxide solution?

5. A solution contains 22.5g of methanol(𝐶𝐻₃𝑂𝐻), dissolved in sufficient water to give a total mass of 105.3g. The molar mass of 𝐶𝐻₃𝑂𝐻 is 32. 𝑔/𝑚𝑜𝑙 . What is the molality of the aqueous methanol solution?

Answer 1

1. a. 2.15 %

b. 0.538 g

2. 87.2 %

3. 4•10^-6

4. 1.04 M

5. 8.49 mol/kg