Tables, Data and Graphs

Question 1

Tables and data

Most experiments generate numerical data which must be accurately recorded.

This is best done using a table with clearly labelled columns indicating the data and units.

Graphs are then drawn and used to visually represent the experimental data.

This process makes it easier to …

Answer 1

identify relationships between the variables plotted and identify trends and variations in data.

Question 2

Drawing graphs

rules, things to do

Answer 2

Every graph should have a title and labels on each axis with the units included.

The units should be written as quantity/units on each axis e.g: for an axis label which represents time, then it should be labelled as Time/s.

Unless the question states otherwise:

plot the independent variable (the variable you control, such as the time you take on observations) on the x-axis (horizontal axis)

plot the dependent variable (the variable you are measuring) on the y-axis (vertical axis)

For the title, the convention is to state the dependent variable first e.g: a graph titled “Graph of height versus time” means that the dependent variable is height and thus is on the y-axis.

A bar graph is used if one set of data is categories or words and a line graph is used if both sets of data are numbers.

The scale you choose should use as much of the graph paper as possible with equal spacings between each point on the scale.

The plotted points should be drawn clearly, using a cross instead of a dot or a circle.

This makes it easier to draw and leaves the option of using a circle to identify anomalous results.

Straight line graphs should be drawn with a ruler.

The line of best fit can be straight or curved as long as it has the same number of points above and below the line and should avoid anomalous points.

Smooth line graphs should be curves with no straight-line sections drawn with a ruler.

Clear construction lines should be used where applicable, which are parallel to the axis and show how you worked out your answer.

Question 3

Graphs should be drawn in

Answer 3

sharp pencil only.

Question 4

Answer 4

Question 5

Answer 5

Question 6

Answer 6

Question 7

EXPLANATION

Answer 7

Compared to a reaction with a reactant at a low concentration, the graph line for the same reaction but at a higher concentration has a steeper gradient at the start and becomes horizontal sooner.

This shows that with increased concentration of a solution, the rate of reaction will increase.

Question 8

EXPLANATION

Answer 8

Compared to a reaction with lumps of reactant, the graph line for the same reaction but with powdered reactant has a steeper gradient at the start and becomes horizontal sooner.

This shows that with increased concentration of a solution, the rate of reaction will increase.

Question 9

Answer 9

Explanation:

The diagram shows that when a catalyst is used, the activation energy is reduced as it creates an alternative pathway requiring lower activation energy, allowing more successful and frequent collisions.

This shows that when a catalyst is used, the rate of reaction will increase.

Question 10

Answer 10

Explanation:

Compared to a reaction at a low temperature, the graph line for the same reaction but at a higher temperature has a steeper gradient at the start and becomes horizontal sooner.

This shows that with increased temperature, the rate of reaction will increase.