Chapter 9: Calculations & Conversions

Question 1

True or False

A solution is a homogeneous mixture of 2 or more constituents

Answer 1

True

Question 2

True or False

A simple way to convert from % to mg/mL is to move the decimal point two places to the right

Answer 2

False
Move the decimal one place to the right
1% = 10 mg/mL

Question 3

True or False

A 1-molar solution of a compound contains the molecular weight (MW) in grams of that compound per liter of solution

Answer 3

True

Question 4

True or False

Dose is a term meaning how much of a drug is given per unit of body weight

Answer 4

False
Dose= the amount of drug given at one time
Dosage= how much of a drug given per unit of body weight

Question 5

True or False

When determining the route of administration, the abbreviation PO means to give by mouth or orally

Answer 5

True

Question 6

True or False

The abbreviation SID means to give the drug to an animal 3 times a day

Answer 6

False

SID= once per day

Question 7

Calculate the area of a cage that is 9 in wide x 10 in long

Answer 7

=9in X 10 in

=90 in^2

Question 8

2.2 lb = _____ kg

Answer 8

2.2 lb = 1 kg

Question 9

1 in = _____ cm

Answer 9

1 in = 2.54 cm

Question 10

10 mL = _____ cc

Answer 10

10 mL = 10 cc

Question 11

A male weight has the following weights over 5 weeks. Calculate the average weight for that time period
1- 250 g
2- 287 g
3- 313 g
4- 334 g 
5- 352 g

Answer 11

250+287+313+334+352/5 = 307.2 g average weight

Question 12

If a 9kg bag of feed costs $34, what is the cost per kg?

Answer 12

34/9 = 3.78/kg

Question 13

A colony of 10 Guinea pigs is fed 35g of feed per animal per day. How many 10-lb bags of feed would you need each week?
(0.001kg/g and 2.2lb/kg)

Answer 13

10 X 35= 350g feed/day
350g X 7 days = 2450g/week
2450g X 0.001kg/g = 2.45kg/week
2.45 kg X 2.2 lb/kg = 5.39 lb/wk
5.39lb / 10lb bag = 0.54 bag/wk

Question 14

A medication is written as: Keflex 1g PO BID. 500 mg capsules are available.
(1000mg/g)

Answer 14

1 g X 1000mg/g / 500 mg/cap = 2 caps

2 caps twice daily by mouth

Question 15

A veterinarian writes an order for a 90g hamster to have 4 mg/kg of a liquid medication SQ. This medication comes in a concentration of 1.0 mg/mL. How many mL will you administer?
(0.001kg/g)

Answer 15

90g X 0.001g/kg = 0.09 kg body weight

0. 09kg X 4mg/kg = 0.36mg
1. 36mg / 1.0mg/mL = 0.36mL

Question 16

You have a order to give 1.5mg/kg of dexmethosone sodium phosphate to a 53.5 lb dog. The drug in the vial has a concentration of 5mg/mL. How many mL of dexmethosone does the dog need?
(2.2lb/kg)

Answer 16

53.5lb / 2.2lb/kg = 24.32 kg body weight
24.32kg X 1.5mg/kg = 36mg
36mg / 5mg/mL = 7.2 mL

Question 17

You want to draw into a syringe 75mg of a preparation which has a drug concentration of 25 mg/mL. What is the volume you need?

Answer 17

25mg/1mL = 75mg/x mL
25mg X x mL = 75mg X 1 mL
x mL = 75mg x 1 mL / 25 mg
x mL = 3 mL

Question 18

How many milliliters of 5% solution thiamylal should be drawn up in a syringe for a 50lb dog if the dosage is 20mg/kg.
(2.2lb/kg)

Answer 18

50 lb / 2.2lb/kg = 22.7kg
22.7kg X 20mg/kg = 454mg
5% solution = 50mg/mL
454mg / 50mg/mL = 9mL

Question 19

To reconstitute a 1000mg bottle of a freeze-dried drug to yield a 2% solution, what volume of diulent should you have ready for filling the bottle to its 2% mark?

Answer 19

2% = 20mg/mL

1000 mg / 20 mg = 50 mL

Question 20

How many milliliters of a 100mg/mL solution of enrofloxacin should a 23.8lb mini pig receive if the dosage is 3.5 mg/kg?
(2.2lb/kg)

Answer 20

23. 8lb / 2.2 kg = 10.8kg
24. 8kg X 3.5mg/kg = 37.8mg
25. 8mg / 100mg/mL = 0.37mL

Question 21

Using the following information, how many grams of calcium chloride (CaCl2) would be needed to a L of a 2 molar solution?
Atomic weights : Ca 40.1 Cl 35.5

Answer 21

Ca: 40.1g X 1 atom = 40.1g in 1 mole
Cl: 35.5g X 2 atom = 71.0g in 1 mole
40.1g + 71g = 111.1g CaCl2 in 1 mole of 1 L of a 1M solution
111.1 X 2 = 222.2g CaCl2 in 2 moles in 1 L of a 2M solution