Maths

• Standard deviation equation: sum of (one value - mean) / number of values - 1, overall square root
• The standard deviation is the average distance from the mean
• The lower the standard deviation the more reliable and consistent the data
• Percentage increase = final - initial / initial x 100
• Percentage uncertainty = uncertainty x number of times measured / amount measured x 100
• percentage change

  final - initial / initial x 100
• to calculate a rate

  1 / time taken
• circumference of a circle

  2 x pi x radius
• area of a circle

  pi x radius ^2
• surface area of a cuboid

  2 x (length x bases + base x height + length x height)
• volume of a cuboid

  length x base x height
• calculate mean

  total of the values / number of values
• percentage yield

  ( actual / theoretical ) x 100
• percentage error

  ( 2 x absolute uncertainty / quantity measured) x100
• magnification

  image / actual
• Rf value

  solute distance / solvent distance
• rate

  change in quantity / time taken
• SA:V ratio

  SA/V