Question 1

Which of the following best describes a systematic (determinate) error in a chemical measurement?

Accepted Answer

An error that can be detected and corrected, such as a miscalibrated instrument.

Question 2

A student measures the mass of a sample three times and obtains the following values: 2.134 g, 2.132 g, and 2.135 g. Which statement best describes these measurements?

Accepted Answer

They are precise but not necessarily accurate.

Question 3

Which of the following numbers has three significant figures?

Accepted Answer

$$0.00420$$

Question 4

What is the correct result for the following calculation, expressed with the proper number of significant figures: $$4.51 	imes 3.6666$$?

Accepted Answer

$$16.5$$

Question 5

A laboratory balance gives a reading of $$2.1803 g. $$How many significant figures does this measurement have?

Accepted Answer

5

Question 6

Which of the following is an example of an exact number?

Accepted Answer

The number of students in a classroom.

Question 7

A student adds $$89.332 cm $$and $$1.1 cm. $$What is the correct answer with the proper number of decimal places?

Accepted Answer

$$90.4 cm$$

Question 8

Which of the following best describes the difference between precision and accuracy?

Accepted Answer

Precision refers to how reproducible measurements are, while accuracy refers to how close a measurement is to the true value.

Question 9

Express $$0.00000772 in $$scientific notation with three significant figures.

Accepted Answer

$$7.72 	imes 10$$^{-6}$$

Question 10

A student calculates the density of a liquid as $$6.8 g $$divided by $$112.04 cm$^3. $$What is the correct answer with the proper number of significant figures?

Accepted Answer

$$0.061 g/cm$^3$$

Question 11

Which of the following is the correct way to round $$8.35 cm to $$two significant figures?

Accepted Answer

$$8.4 cm$$

Question 12

Convert $$1.63 L to mL $$using dimensional analysis.

Accepted Answer

$$1.63 	imes 10^3$ mL

Question 13

The speed of sound in air is $$343 m/s. $$Convert this speed to miles per hour ($$1 mi$$ $$= 1609 m).$$

Accepted Answer

$$767 mi/h$$

Question 14

Which of the following statements about significant figures is correct?

Accepted Answer

Zeros between nonzero digits are significant.

Question 15

A measurement is reported as $$0.003382 m$^3. $$How many significant figures does this value have?

Accepted Answer

4

Question 16

Which of the following is the correct result for $$(4.0 	imes 10$$^{-5}$$) 	imes (2.0 	imes 10$$^{3}$$)$$?

Accepted Answer

$$8.0 	imes 10$$^{-2}$$

Question 17

A student measures the diameter of a coin four times and gets: $$28.246$$, $$28.244$$, $$28.242$$, $$28.248 mm. $$The accepted value is $$28.054 mm. $$What is the absolute error of the average measurement?

Accepted Answer

$$0.192 mm$$

Question 18

Which of the following best describes a random (indeterminate) error?

Accepted Answer

An error that occurs due to unknown and uncontrollable factors, causing small variations in repeated measurements.

Question 19

Which of the following is the correct way to express $$568.762 in $$scientific notation with five significant figures?

Accepted Answer

$$5.6876 	imes 10$$^{2}$$

Question 20

When adding or subtracting measured values, the result should be reported with:

Accepted Answer

The same number of decimal places as the value with the fewest decimal places.

Cifras Significativas, Notación Científica e Incertidumbre en Mediciones

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