Ratios and Prportions

Question 1

Define ratios

Answer 1

The relative magnitude of two quantities

Question 2

Define proportion

Answer 2

The expression of the equality of two ratios

Question 3

If 3 tablets contain 975 milligrams of aspirin, how many
milligrams should 12 tablets contain?

Answer 3

3900mg

Question 4

What is meant by strength

Answer 4

Concentration

Question 5

Unit of mass and liquid when calculating the percentage of strength

Answer 5

g, mL

Question 6

What do these expressions mean?
w/w
w/v
v/v
v/w

Answer 6

weight in weight
weight in volume
volume in volume
volume in weight

Question 7

How many grams of zinc oxide are needed to make 240g of a 4% (w/w) zinc oxide ointment?

Answer 7

9.6g

Question 8

Express 70 mL of pure alcohol dispersed with water to a total volume of 120mL as a percentage

Answer 8

70/120 = 0.5833
0.5833 × 100 = 58.33%

Question 9

When a pharmaceutical formula is expressed as a percentage without specifying the units of weight or measure, what are the units used?

Answer 9

Liquids are measured by volume.
Solids are measured by weight.

Question 10

How much Aspirin is in 10 mL of a 100 mL mixture of Aspirin of strength 10% w/v?

Answer 10

10g —> 100mL
? —> 10mL
Answer = 1g