Practical Calculations

Question 1

AD
AS
AU

Answer 1

Right ear
Left ear
Both ears, each ear

Question 2

ad lib

Answer 2

As much as desired

Question 3

gt
gtt

Answer 3

Drop
Drops

Question 4

mEq

Answer 4

milliequivalent

Question 5

OD
OS
OU

Answer 5

Right eye
Left eye
Both eye, each eye

Question 6

3 systems of measurement

Answer 6

1. Metric
2. Apothecary
3. Household

Question 7

Fundamental units of measurement in the metric system (weight, volume, length)

Answer 7

Gram
Liter
Meter

Question 8

Units of measure for the biological sciences
Metric System

Answer 8

Base (gram, liter, meter) 1
Kilo 1000
Deci 1/10
Centi 1/100
Milli 1/1000
Micro 1/1,000,000
Nano 1/1,000,000,000
Pico 1/1,000,000,000,000

Question 9

Convert 3000 mg to grams

Answer 9

3000 mg
3000 mg x 1 g
1000 mg
Cancel the mg
1 / 1000 = 0.001
0.001 x 3000 = 3

Question 10

Stair step method - converting metric units

Answer 10

Divide by 10 each step up (move decimal one place to the left)
Multiply by 10 each step down (move decimal one place to the right)

Question 11

Apothecary System

Answer 11

Minim italics m or min
Dram italics dr
Ounce italics oz
Grain italics gr

Question 12

minim =

Answer 12

1 drop
Always expressed as a whole number

Question 13

1 fluid dram =

Answer 13

4 ml

Question 14

1 oz =

Answer 14

30 ml

Question 15

1 grain =

Answer 15

64.8 (65) mg

Question 16

Household system

Answer 16

Drop / gtt
Tablespoon / tbsp
Teaspoon / tsp

Question 17

1 Tbsp =

Answer 17

15 ml

Question 18

1 tsp =

Answer 18

5 ml

Question 19

1 oz =

Answer 19

30 ml

Question 20

Solvent

Answer 20

Solution capable of dissolving other substances

Question 21

Solute

Answer 21

Substance that is dissolved in a liquid (solution)

Question 22

Miscible / immiscible

Answer 22

Substances that form solutions /
Those that do not

Question 23

Saturated

Answer 23

Containing the maximum amount of solute at a particular temperature and pressure

Question 24

Suspension

Answer 24

Mixes of substances in which the solute is made up of very large particles

Question 25

The strength of a mixture is expressed as a parts ratio or

Answer 25

Ratio concentration

Question 26

A 1:32 dilution means

Answer 26

1 part drug to 31 parts solvent to make 32 parts total

Question 27

Parts per million (ppm) =

Answer 27

1 mg of a solute in a kg or liter of solvent Or 1 mcg of solute in a gram or ml

Question 28

Parts per billion (ppb)

Answer 28

1 mcg in a kg or liter 1 nanogram in a gram or ml

Question 29

1:32 as a percent concentration

Answer 29

1:32 = Y:100 1 = Y 32 100 32Y = 100 32 32 Y = 3.1%

Question 30

How can concentrations be expressed

Answer 30

Parts ratio Liquids - rate per volume Liquids - volume per volume Solids - weight per weight

Question 31

Percent concentration

Answer 31

Parts of a solute per 100 parts of the solution Percent w/v = grams of solute in 100 ml solution Percent w/w = grams of solute in 100 g of diluent Percent v/v = ml of solute in 100 ml solution

Question 32

Convert a % solution to mg/ml 5% Lasix solution = x mg/ml

Answer 32

Multiply the % x 10 50 mg/ml

Question 33

Convert a solution in mg/ml to a % 50 mg/ml lasix = x%

Answer 33

Divide the mg/ml by 10 50 / 10 = 5%

Question 34

Mg% meaning

Answer 34

Number of mg in 100 ml of solution Or mg per deciliter (100 ml)

Question 35

100% solution (w/w) = 5% solution =

Answer 35

100 g solute in 100 g solvent 5 g in 100 g solution 5 g + 95 g

Question 36

100% solution v/v = 10% solution =

Answer 36

Pure drug/chemical 10 ml chemical in 100 ml solution

Question 37

Diluting up aka

Answer 37

qs or quantity sufficient

Question 38

How many grams of sodium chloride are needed to make 1 L of 0.9% sodium chloride?

Answer 38

Total volume of final drug solution x concentration = amount grams needed = 0.9 x 1000 ml 100 9 grams

Question 39

What percentage is a solution that contains 9 g of sodium chloride?

Answer 39

Percent solution = grams of solute x 100 Volume of solution 9 x 100 = 900 1000 1000 0.9%

Question 40

What formula would be used to change the concentration (dilute) a solution?

Answer 40

V1 x C1 = V2 x C2 What you have on hand = what you want to make V1 volume of stock solution/amount to use to prepare new volume C1 original concentration of stock solution V2 desired final volume C2 desired final concentration

Question 41

How would you prepare 100 ml of a 5% dextrose solution from a 50% dextrose solution?

Answer 41

V1 x 50% = 100 ml x 5% V1 x 50 = 500 ml V1 = 10 ml

Question 42

When would you use milliequivalents?

Answer 42

When electrolytes are involved

Question 43

An equivalent weight =

Answer 43

1 g molecular weight divided by the total positive valence of the material in question.

Question 44

The concentration of an electrolyte solution is expressed as

Answer 44

mEq/L

Question 45

Standard drip set vs micro drip. How many drops/ml?

Answer 45

15 60

Question 46

Formula to calculate fluid drip rates

Answer 46

Volume of infusion (ml) x drop factor (gtt/ml) Time of infusion (min) = drops per min

Question 47

CRI

Answer 47

Constant rate infusions