Module 7

Question 1

What is the correct order, from most polar to least polar, of the following solvents commonly used in the extraction of medicinal plants?

Answer 1

water > glycerine > ethanol > acetic acid > acetone > ethyl acetate > hexane

Question 2

You have a solution consisting of 20 grams of solute in 100 milliliters of solution. 100 mL of the solution weighs 150 grams. What is the weight/volume and weight/weight percent concentration of this solution?

Answer 2

20 %; 13.3 %

Question 3

Solution #1 is made from 50 grams of sucrose and 1 liter of vodka. Solution #2 is made from 25 grams of sodium chloride and 1 liter of water. Which solution is an electrolyte? Which substances are the solutes? Which are the solvents?

Answer 3

salt/water; salt & sugar; water & vodka

Question 4

You have an herbal extract which is a heterogeneous mixture of many different particle sizes. Over time, some of these particles settle out to form a distinct layer on the bottom of the bottle. Which term best describes this extract?

Answer 4

suspension

Question 5

What is the molarity of a solution made by diluting 100 mL of 0.5 M hydrochloric acid with water to form a total volume of 1.5 liters? (M1)(V1) = (M2)(V2); M=mol solute/L solution

Answer 5

3.3 x 10-2 M

Question 6

Which of the following parameters does not give us quantitative information regarding the concentration of total extractives per unit of a finished botanical extract?

Answer 6

ethanol/water ratio

Question 7

Which of the following parameters are not mainly dependent on or affected by the concentration of a solution?

Answer 7

Conductivity

Question 8

Which type of reaction does the following example represent? NaCl(aq) + AgNO3 (aq) → AgCl(s) + NaNO3 (aq)

Answer 8

Precipitation

Question 9

The formula weight of sodium hydroxide is ~ 40 grams/mole. If 20 grams of NaOH is dissolved in 2.0 liters of water, what is the molarity of the solution?

Answer 9

0.25 M

Question 10

The solubility of sucrose in water has been established to be approximately 212 g per 100 mL at 25°C. Which of the following statements is correct based on this information?

Answer 10

At 25°C, a saturated solution of sucrose in water will contain ~ 2.12 kilograms of sucrose in one liter of water