Standard Level Content
Unit 1 · IB Chemistry
Measurement & Uncertainty
The foundation of quantitative chemistry, focusing on the precision of measurements, propagation of uncertainties, and data analysis.
Lesson Slideshow Section 01
Unit Summary Section 02
Key Concepts
Significant Figures, Random vs Systematic Error, Absolute/Percentage Uncertainty, Precision vs Accuracy
Assessment Objectives
Identify uncertainty, Calculate absolute/percentage uncertainty, Evaluate experimental errors
Prior Knowledge Needed
Basic algebra, scientific notation, metric system conversions
IB Syllabus Reference
S1.1
Interactive Study Guide
Click here to view the full, detailed topic summary for this unit.
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Video Lesson Section 03
Video Instruction
2 Lessons Available
Errors and Uncertainty
Graphing Data
Practice Quiz Section 04 · Interactive
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Vocabulary Review Section 05
Accuracy
The closeness of a measurement to the true or accepted value.
Precision
The closeness of agreement between independent measurements of a quantity under the same conditions.
Systematic Error
An error that results in a consistent bias in one direction, often due to faulty equipment calibration.
Random Error
Natural fluctuations in measurements that can be reduced by repeated trials and averaging.
Absolute Uncertainty
The margin of uncertainty associated with a measurement, expressed in the same units ($e.g. \pm 0.05 \text{ cm}^3$).
Fractional Uncertainty
The ratio of the absolute uncertainty to the measured value.
Percentage Uncertainty
The fractional uncertainty expressed as a percentage ($x/y \times 100\%$).
Significant Figures
The number of digits that carry meaning contributing to the precision of a measurement.
Line of Best Fit
A smooth line that reflects the general trend of data points on a graph, potentially ignoring outliers.
Propagation of Error
The calculation of total uncertainty when combining multiple measurements (sum/difference/product).
Experimental Yield
The actual amount of product obtained from a chemical reaction in the laboratory.
Standard Solution
A solution of accurately known concentration.
Calibrate
The process of adjusting an instrument to ensure its accuracy against a known standard.
Limit of Detection
The smallest amount or concentration of a substance that can be reliably detected by an analytical method.
Independent Variable
The variable that is deliberately changed in an experiment.
Dependent Variable
The variable that is measured or observed in response to changes in the independent variable.
Parallax Error
The shift in apparent position of an object when viewed from different angles, affecting measurement readings.
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Revision Notes Section 06
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Practice Tests Section 07
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Worksheets & Labs Section 08