Measurements and Significant Figures

These flashcards cover key concepts about exact and measured numbers, the importance of significant figures, and the methodology for accurate measurements in a lab setting.

What is an exact number?

An exact number is something you can count, like one pencil or three chairs, or a definition such as a thousand meters in a kilometer.

What are measured numbers?

Measured numbers are values obtained from measurements using instruments like rulers, balances, or graduated cylinders.

How to differentiate between significant figures in measurements?

Significant figures in measurements depend on the precision of the measuring instrument; more decimal places indicate more precise measurements.

Why do zeros matter in significant figures?

Trailing zeros in whole numbers are generally not significant unless indicated by a decimal point. They may result from rounding, which affects their significance.

What is the role of the meniscus in reading measurements?

The meniscus is the curved surface of a liquid in a container. You should read the bottom of the meniscus at eye level for an accurate measurement.

How do you express uncertainty in measurements?

Uncertainty can be expressed as a range, for example, ±0.01 mL depending on the precision of the measuring instrument used.

What is the rule for rounding when multiplying or dividing measurements?

When multiplying or dividing, round the final answer to the least number of significant figures in any of the measurements used.

How do you round measurements for addition and subtraction?

For addition and subtraction, round the answer to the least number of decimal places in the measurements.

What is the significance of using proper measuring instruments?

Using appropriate instruments ensures accuracy; not utilizing the full precision of a more expensive instrument would lead to inaccurate reporting.

What are significant figures in the context of this lab?

Significant figures indicate how precisely a measurement is known and include all certain digits plus one estimated digit.