Maths skills

Question 1

how do you find the margin of error

Answer 1

it is half the smallest scale divison on the instrument

Question 2

what is the equation to calculate percentage error

Answer 2

uncertanty / reading x 100

Question 3

how do you calculate percentage increase

Answer 3

final - inital
—————– x 100%
initial

Question 4

why are orders of magnitude and logarithms used

Answer 4

when large values are being compared / there is a wide range of values so the values can fit on the graph

Question 5

what are the 3 ways to caluclate rate of reaction?

Answer 5

1) change in conc / time
2) change in volume / time
3) 1 / time

Question 6

how do you calculate rate on a curved graph

Answer 6

draw a tangent from the steepest part of the graph, that touches a point on the curve, then find change in y / change in x

Question 7

what is standard deviation

Answer 7

it describes how spread out a group of numbers are (the variation around the mean value)

Question 8

how is standerd deviation represented on a graph

Answer 8

as error bars

Question 9

how do you compare data with standerd deviation

Answer 9

do the standered deviations overlap?
- if yes, the difference in data is not significant
- if no, the difference in data is significant