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Exercise - units and conversions
Worked Exercises
- Write conversion factors for the following units:
a) Litres and millilitres
b) Ounces and grams.
a) \(1L=1000ml\)
\(\frac{1L}{1000g}\) and \(\frac{1000g}{1L}\)
b) \(1oz=28.3g\)
\(\frac{1oz}{28.3g}\) and \(\frac{28.3g}{1oz}\)
- Convert \(3.500lb\) pounds to grams (\(1lb=454g\)).
Relationship between two units - \(1lb=454g\)
Conversion factors - \(\frac{1lb}{454g}\) and \(\frac{454g}{1lb}\)
Only one of these conversion factors is required to convert pounds to grams. The conversion factor, \(\frac{454g}{1lb}\) , is required as it allows for the cancellation of the pound units, leaving gram as the new unit.
\( \frac{454g}{1lb}\times3.500lb=1589g \)
Exercises
Write the conversion factors for the following:
1. Centimetres and metres
\(1m = 100cm \)
\(\frac{1m}{100cm}\: \textrm{and} \frac{100cm}{1m} \)
2. micromoles and moles
\(1mol = 10^{-6}\mu mol \)
\(\frac{1mol}{10^{-6}\mu mol}\: \textrm{and} \frac{10^{-6}\mu mol}{1mol} \)
3. litres and gallons (\(1L=0.265gal\))
\(1L = 0.265gal \)
\(\frac{1L}{0.265gal}\: \textrm{and} \frac{0.256gal}{1L} \)
4. microlitres and millilitres
\(1000\mu L = 1mL \)
\(\frac{1000\mu L}{1ml}\: \textrm{and} \frac{1ml}{1000\mu L} \)
Convert
1. \(2.56gal\) gallons to litres (\(1L=0.265gal\))
\(\frac{1L}{0.265gal}\times2.65gal=10.0L\)
2. \(250.0mg\) to grams
\(\frac{1g}{1000mg}\times250.0mg=0.2500g\)
3. \(750.0\mu mol\) to millimoles
\(\frac{1mmol}{1000\mu mol}\times750.0\mu mol=0.7500\)
4. \(0.567ml\) to microlitres
\(\frac{1000\mu l}{1ml}\times0.567ml=567\mu L\)
5. Convert 45 km/h to m/s
12.5 m/s
6. Convert 26 m/s to km/h
93.6 km/h