IB Chemistry HL cheat sheet
IB Chemistry HL · Keep the key ideas within reach.
Structure
Scientific method: hypothesis → controlled experiment → data → analysis → conclusion; a hypothesis must be falsifiable and testable.
Independent variable is manipulated, dependent variable is measured, and controlled variables are held constant and reported.
Reliability is improved by repeating measurements and calculating a mean; validity requires the measurement to actually test the research question.
A control group provides a baseline against which the effect of the independent variable is compared.
Data presentation: choose a graph type appropriate to the data (line for continuous, bar for categorical) and label axes with quantity and unit.
Uncertainty propagation: when a calculated quantity depends on several measured values, combine percentage uncertainties; quote the final result as value ± uncertainty with correct significant figures.
Conclusions must be limited to the range of data collected; extrapolation beyond the measured range is unjustified without a theoretical model.
Ethical and safety considerations: risk assessment, appropriate disposal of chemicals, and informed consent where human participants are involved.