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Lecture 1 Practice: Units in Biopharmaceutical Engineering

Twelve short problems in different formats: predicting whether a number gets bigger or smaller, true or false, matching equal amounts, a quick-fire round with new numbers every time, finding a mistake, and multi-part problems that end in a workplace decision. If units are new to you, or it has been a while, start with Problem 1 and open How to convert any unit. Each answer is checked as you go, and the working is shown once each step is correct.

Toolbox: conversion factors

Temperature

  • K = °C + 273.15
  • °F = 1.8 × °C + 32
  • °C = (°F − 32) ÷ 1.8

Pressure

  • 1 atm = 101.325 kPa = 760 Torr
  • 1 bar = 105 Pa = 100 kPa
  • 1 bar = 14.5 psi
  • 1 kPa = 1,000 Pa

Volume

  • 1 m3 = 1,000 L = 106 cm3
  • 1 L = 1,000 mL
  • 1 mL = 1 cm3

Mass and amount

  • 1 g = 1,000 mg
  • 1 mg = 1,000 µg
  • 1 lb = 0.4536 kg
  • moles = mass ÷ molar mass

Energy and time

  • 1 Wh = 3,600 J
  • 1 kJ = 1,000 J
  • 1 h = 60 min = 3,600 s
How to convert any unit
  1. Write the conversion factor as a fraction equal to 1, for example 1,000 mL / 1 L.
  2. Put it the way up that cancels the unit you don't want: 2.5 L × (1,000 mL / 1 L) = 2,500 mL.
  3. For squared or cubed units, square or cube the factor: 1 m3 = (100 cm)3 = 106 cm3.
  4. For two units at once, such as L h−1 to mL min−1, convert one unit at a time.
  5. Sense-check: converting into a smaller unit should give a bigger number, and the other way round.

About the questions

  • The conversion factors are those in the Lecture 1 slides, collected in the toolbox.
  • Small rounding differences are accepted, so you do not need to match every decimal place.
  • The quick-fire round gives different conversions and numbers every time, so you can come back to it as often as you like.
  • Your answers are saved in this browser, so you can leave and come back later.