Lab Test 1 Unit Conversions

Question 1

Molarity

(Molar Concentration)

Symbol: M, c

Answer 1

Moles (gram molecular weights) of solute in 1- liter solution

Question 2

Normality

(N)

Answer 2

Gram equivalent weights of solute in 1-liter solution

Question 3

Molality

(m)

Answer 3

Moles of solute in 1000 grams of solvent

Question 4

Mole Fraction

(X, N)

Answer 4

Ratio of the moles of one constituent (e.g. the solute) of a solution to the total moles of all constituents (solute+solvent)

Question 5

Percent by weight

Answer 5

Grams of solute in 100 grams of solution

Question 6

Percent by volume

Answer 6

Milliliters of solute in 100 ml of solution

Question 7

Percent weigh-in-volume

Answer 7

Grams of solute in 100 ml of solution

Question 8

Milligrams per cent

(mg%)

Answer 8

Milligrams of solute in 100 ml of solution

Question 9

Parts per million:

Answer 9

The number of milligrams of solute per kg of solution = one ppm, since 1 mg = 10^-3g and 1 kg = 10³g

Assuming the density of water is 1.00 g/mL, 1 liter of solution = 1kg and hence, 1mg/L = 1ppm. This is generally true for freshwater and other dilute aqueous solutions.

To convert concentrations in mg/L (or ppm in dilute solution) to molarity, divide by the molar mass of the analyte to convert mass in mg into a corresponding number of moles.

Question 10

A common clinical expression of concentration is:

Answer 10

milligrams per 100 mL solution (mg/100mL)

For example, normal fasting levels of glucose in the blood are 80-90 mg of glucose per 100 mL of whole blood volume. This is most often expressed as 80-90 mg/dl, since 1 dl= 100 mL. Sometimes this is also expressed as mg%.

Question 11

Metric Prefixes

Answer 11

Question 12

Mass and Volume Units

Answer 12

Question 13

Equations

Answer 13

Question 14

Expression of dilution

Answer 14

When water is added to relatively concentrated