Question 1

Which of the following best describes a measured number in chemistry?

Accepted Answer

A number obtained by using a measuring tool, such as a ruler or balance.

Question 2

A student measures the length of a pencil using a ruler marked in millimeters. The pencil ends between the 12.0 cm and 12.1 cm marks, and the student estimates the length as 12.05 cm. How many significant figures are in this measurement?

Accepted Answer

4

Question 3

Which of the following numbers contains three significant figures?

Accepted Answer

$$0.00476$$

Question 4

Which of the following statements about zeros in significant figures is correct?

Accepted Answer

Zeros at the end of a decimal number are significant.

Question 5

Which of the following is an exact number?

Accepted Answer

The number of students in a classroom.

Question 6

How many significant figures are in the measurement $$0.0080 g$$?

Accepted Answer

2

Question 7

A nurse needs to prepare a solution by mixing $$25.300 mL of $$saline. How many significant figures are in this measurement?

Accepted Answer

5

Question 8

Which of the following measurements is reported with the correct number of significant figures if the ruler is marked every $$0.1 cm $$and the object ends between $$4.5 cm $$and $$4.6 cm$$?

Accepted Answer

$$4.55 cm$$

Question 9

Which of the following numbers has four significant figures?

Accepted Answer

$$0.04050$$

Question 10

A laboratory balance gives a mass reading of $$0.2500 g. $$Which statement about the zeros in this measurement is correct?

Accepted Answer

All zeros are significant.

Question 11

Which of the following is the correct scientific notation for the number $$0.002650 m$$, showing all significant figures?

Accepted Answer

$$2.650 	imes 10$$^{-3}$$ m

Question 12

A student records the following measurements: $$0.00307 g$$, $$2.05 	imes 10^3$ mL, and 5.80$$ 	imes $$10^2 L. $$Which measurement contains three significant figures?

Accepted Answer

$$2.05 	imes 10^3$ mL

Question 13

Which of the following best explains why exact numbers do not affect the number of significant figures in a calculation?

Accepted Answer

They are defined values or counted quantities with no uncertainty.

Question 14

A patient’s temperature is measured as $$37.00$$ °C. How many significant figures are in this measurement?

Accepted Answer

4

Question 15

Which of the following measurements contains only one significant figure?

Accepted Answer

$$0.008 g$$

Question 16

A chemist writes $$44,000 L as$$ $$4.4 	imes 10^4$ L. How many significant figures are in this measurement?

Accepted Answer

2

Question 17

Which of the following is a measured number and not an exact number?

Accepted Answer

A beaker contains $$250 mL of $$water.

Question 18

A student measures the mass of a sample as $$0.0500 g. $$Which zeros are significant?

Accepted Answer

Both zeros after the decimal point.

Question 19

Which of the following best describes the process of reporting a measured length using a ruler?

Accepted Answer

Estimate the last digit by visually dividing the space between the smallest marked lines.

Question 20

A solution is prepared by mixing $$1.00 L of $$water with $$250 mL of $$ethanol. Which of the following statements is true regarding significant figures in this context?

Accepted Answer

$$1.00 L $$has three significant figures, while $$250 mL $$has three.

Chapter 2: Chemistry and Measurements – Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard