Mass Conversions |
Key Concepts
- Mass is a direct measure of the amount of matter in an object.
- The SI unit of mass is the kilogram which is given the symbol kg .
- Chemists in a laboratory usually deal with much smaller masses than kilograms, often grams or milligrams, so we need to be able to convert from one unit of mass to another.
Mass Conversions
SI Unit Conversions
| factors |
1012 |
109 |
106 |
103 |
102 |
101 |
10-1 |
10-2 |
10-3 |
10-6 |
10-9 |
10-12 |
10-15 |
10-18 |
|---|
| prefix |
tera |
giga |
mega |
kilo |
hecto |
deca |
deci |
centi |
milli |
micro |
nano |
pico |
femto |
atto |
|---|
| symbol |
T |
G |
M |
k |
h |
da |
d |
c |
m |
µ |
n |
p |
f |
a |
|---|
| 1 kilogram (1kg) = 103 grams (1000g) |
1 gram (1g) = 1 ÷ 103 kilograms = 0.001kg |
| 1 milligram (1mg) = 10-3 grams (0.001g) |
1 gram (1g) = 1 ÷ 10-3 milligrams = 1,000mg |
| 1 microgram (1µg) = 10-6 grams |
1 gram (1g) = 1 ÷ 10-6 micrograms = 106µg |
Examples of Mass Conversions Using SI Units
- Convert 1 kilogram to grams
From the table above we see that kilo = 103 = 1,000
1 kg = 1,000 g
- Convert 2.5kg to grams
1kg = 1,000 g
2.5 kg = 2.5 x 1,000g = 2,500 g
- Convert 5 milligrams to grams
From the table above we see that milli = 10-3
5mg = 5 x 10-3g = 0.005g
- Convert 250g to kilograms
1,000g = 1kg
1g = 1 ÷ 1,000 kg = 0.001 kg
250g = 250 ÷ 1,000 = 0.250 kg
- Convert 25 µg to kilograms
1 µg = 10-6g
25 µg = 25 x 10-6g = 2.5 x 10-5g
1g = 1 ÷ 1,000 kg
2.5 x 10-5g = 2.5 x 10-5 ÷ 1,000 kg = 2.5 x 10-8kg
Empirical Units of Mass
- 1 ounce = 0.0625 pounds = 28.35 grams
1 oz = 0.0625 lb = 28.35 g
- 1 pound = 16 ounces = 0.4536 kilograms
1 lb = 16 oz = 0.4536 kg
Examples of Conversion Between Empirical Units and SI Units of Mass
- Convert 10 ounces to grams
1 oz = 28.35 g
10 oz = 10 x 28.35 g = 283.5g
- Convert 2.5 pounds to kilograms
1 lb = 0.4536 kg
2.5 lb = 2.5 x 0.4536 kg = 1.134 kg
- Convert 900 grams to pounds
1 lb = 0.4536 kg
and 1 kg = 1,000 g
so 1 lb = 0.4536 x 1,000 g = 453.6 g
so 1g = 1 ÷ 453.6 lb = 0.002205 lb
900g = 900 x 0.002205 lb = 1.9845 lb
- Convert 0.25 pounds to milligrams
1 lb = 0.4536 kg
0.25 lb = 0.25 x 0.4536 kg = 0.1134 kg
and 1kg = 103g
So 0.1134 kg = 0.1134 x 103 g = 113.4g
1 mg = 10-3g
So 1g = 1 ÷ 10-3 mg = 103mg = 1,000mg
113.4g = 113.4 x 103 mg = 113400 mg (1.134 x 105mg)
- Convert 430 milligrams to ounces.
1mg = 10-3g
430mg = 430 x 10-3g = 0.430g
1 oz = 28.35g
So 1g = 1 ÷ 28.35oz = 0.03527oz
0.430g = 0.430 x 0.03527 oz = 0.0152 oz
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Related AUS-e-TUTE Topics |
| Temperature Conversions
Volume Conversions
Density Calculations
Significant Figures
Scientific (exponential) Notation
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