Graphs in Chemistry

Study Notes

Graphs are a visual way to present data, making it easier to observe patterns and identify anomalous results.
A line graph should have at least 5 data points and use a suitable scale to make it easy to plot data.
The graph should occupy at least 2/3 of the graph paper, with each axis labeled with the name and unit of the quantity being plotted.
The data points should be clearly marked, and the points should be joined to form a line of best fit or a smooth curve.
The line must go through the origin for quantities that are directly proportional.

Data can be presented in tables, bar graphs, or line graphs.
The gradient of a line graph can be calculated, and the answer should be given with the appropriate units.
Calculations should show all steps, and the answer should have the same number of significant figures as the measurements used in the calculation.
Avoid excessive rounding, especially in calculations involving moles.

The aim of an experiment should be stated at the beginning of the lab report and should be concise and clear.
The experiment should be set up to allow for the collection of data, such as using a stopwatch or a gas syringe.
The experiment can be modified to change the surface area, concentration of the acid, or temperature to alter the rate of reaction.
The experiment should be designed to allow for the collection of data, such as using a stopwatch or a gas syringe.

Diagrams are an important part of the laboratory report, providing a pictorial representation of the setup used during the experiment.
Diagrams should be drawn using a sharp pencil, with objects in two dimensions, and should not be drawn in 3D.
A science stencil can be used to draw neat diagrams of the appropriate size.
The diagram should be labeled with the names and units of the variables being measured.

Observations should be made during the experiment, including changes in state, color, texture, odors, liberation of a gas, emission or absorption of heat, etc.
These observations should be noted and included in the laboratory report.

Plotting a graph involves drawing the x and y axes, labeling each axis, and identifying the range of data to include.
The data points should be plotted using a plus (+) notation, and the points should be connected with a best straight line or smooth curve.
The graph should be titled, and the steps should be repeated when plotting multiple series of data on the same graph.
Reading a graph involves giving the values for the x and y axes of a given point on the graph.
Interpreting a graph involves understanding how the variables change in relation to each other.

Sketching a graph involves drawing a graph without having specific coordinates.
This skill is used to interpret situations and make predictions based on existing data.

Air is a mixture of gases, including nitrogen, oxygen, carbon dioxide, noble gases, water vapor, and impurities or pollutants.
The composition of air varies from place to place.
Burning fossil fuels contributes to the amount of carbon dioxide, sulfur dioxide, and oxides of nitrogen in the atmosphere.
Oxygen makes up approximately 21% of air.