Units of Measurement and Significant Figures

These flashcards cover fundamental concepts of measurements, significant figures, and related calculations in chemistry.

What are the two components of every measurement?

A measurement has a known value and an estimated value.

What represents the estimated digit in a measurement?

The last digit is the estimated or uncertain number.

What does significant figures represent in scientific measurements?

Significant figures communicate the precision of a measurement.

How should you account for uncertainty in measurements?

Include one estimated digit beyond the known digits.

What are the SI base units for length, mass, and time?

Length: meter (m), Mass: kilogram (kg), Time: second (s).

How is weight different from mass?

Weight is the gravitational pull on matter, while mass is the amount of matter.

What unit is typically used to measure volume in chemistry?

Milliliters (mL) and liters (L).

What is the formula for calculating density?

Density = mass/volume.

What does a negative exponent in scientific notation indicate?

It signifies a small number and involves moving the decimal to the left.

What does a positive exponent in scientific notation indicate?

It signifies a large number and involves moving the decimal to the right.

How do you convert 5,670,000,000 into scientific notation?

5.67 x 10^9.

How do you convert 0.0000005432 into scientific notation?

5.432 x 10^-7.

What is accuracy in measurements?

Accuracy refers to how close measurements are to the accepted value.

What is precision in measurements?

Precision refers to how closely a set of measurements agree with each other.

What are significant figures?

Digits in a measurement that carry meaning contributing to its precision.

Give an example of a number that has four significant figures.

1234 or 0.00456.

How are significant figures determined for a measurement with trailing zeros?

Trailing zeros after a decimal point are significant.

What is percent error?

Percent error represents the percent difference between accepted and experimental values.

What is the average density of water?

1.0 g/cm³.

What factors limit the reliability of measurements?

Skill of the measurer, conditions of the measurement, and the measuring instrument.

How many significant figures are in the measurement 2400?

It depends on the context but usually has 2 significant figures.

For addition/subtraction, how should answers be rounded?

The answer should be rounded to the decimal place of the least precise measurement.

When multiplying or dividing, how should results be rounded?

Results should be rounded to the number of significant figures of the least precise measurement.

What is the conversion factor from feet to inches?

1 ft = 12 in.

What is the result of 4.5 cm + 21.2 cm + 1.33 cm?

The sum is 27.0 cm, rounded to the correct significant figures.

What common mistake should be avoided when dealing with zeros in significant figures?

Confusion between leading and trailing zeros.

What is the significance of conversion factors in measurements?

They allow for unit conversions without changing the value.