Q: Convert 25.0 inches to centimeters. (Given: $$1 \text{ inch} = 2.54 \text{ cm})$$

$$25.0 \times 2.54 = 63.5 \text{ cm}$$

Q: What is the molar mass of water ($$\mathrm{H_2O}$$)? (H: 1.01 g/mol, O: 16.00 g/mol)

$$2 \times 1.01 + 16.00 = 18.02 \text{ g/mol}$$

Q: A sample contains 0.50 mol of sodium chloride ($$\mathrm{NaCl}). $$How many formula units are present? ($$N_A = 6.022 \times 10$$^{23}$$)

$$0.50 \times 6.022 \times 10$$^{23}$$ = 3.011 \times 10$$^{23}$$

Question 1

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

Accepted Answer

Precision refers to how close measurements are to each other, while accuracy refers to how close measurements are to the true value.

Question 2

A student measures the mass of a sample three times and gets values of 2.51 g, 2.50 g, and 2.52 g. The true mass is 2.70 g. Which statement is correct?

Accepted Answer

The measurements are precise but not accurate.

Question 3

Which of the following is the correct number of significant figures in the measurement 0.004560 g?

Accepted Answer

5

Question 4

Convert 25.0 inches to centimeters. (Given: $$1 	ext{ inch} = 2.54 	ext{ cm})$$

Accepted Answer

$$25.0 	imes 2.54 = 63.5 	ext{ cm}$$

Question 5

Which of the following is NOT a physical property of matter?

Accepted Answer

Reactivity with acid

Question 6

Which of the following elements is a non-metal?

Accepted Answer

Chlorine (Cl)

Question 7

What is the charge of an ion formed when a neutral atom of magnesium (Mg) loses two electrons?

Accepted Answer

$$+2$$

Question 8

Which of the following is the correct electron configuration for a neutral oxygen atom ($$Z=8$$)?

Accepted Answer

$$1s^2$$ $$2s^2$$ $$2p^4$$

Question 9

Which group in the periodic table contains the noble gases?

Accepted Answer

Group 18

Question 10

A neutral atom of phosphorus has 15 protons. How many electrons does it have?

Accepted Answer

15

Question 11

Which of the following is the correct formula for aluminum sulfate?

Accepted Answer

$$\mathrm{Al_2$(SO_4$)_3}$$

Question 12

What is the molar mass of water ($$\mathrm{H_2O}$$)? (H: 1.01 g/mol, O: 16.00 g/mol)

Accepted Answer

$$2 	imes 1.01 + 16.00 = 18.02 	ext{ g/mol}$$

Question 13

Which of the following is the correct empirical formula for glucose ($$\mathrm{C_6H_{12}O_6$}$$)?

Accepted Answer

$$\mathrm{CH_2O}$$

Question 14

A compound contains 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mass. What is its empirical formula?

Accepted Answer

$$\mathrm{CH_2O}$$

Question 15

Which of the following ions has the same number of electrons as neon ($$\mathrm{Ne}$$)?

Accepted Answer

$$\mathrm{Na^+}$$

Question 16

Which of the following statements about metals and non-metals is correct?

Accepted Answer

Metals tend to lose electrons to form cations.

Question 17

Which of the following is the correct formula for ammonium nitrate?

Accepted Answer

$$\mathrm{NH_4NO_3}$$

Question 18

A sample contains 0.50 mol of sodium chloride ($$\mathrm{NaCl}). $$How many formula units are present? ($$N_A = 6.022 	imes 10$$^{23}$$)

Accepted Answer

$$0.50 	imes 6.022 	imes 10$$^{23}$$ = 3.011 	imes 10$$^{23}$$

Question 19

Which of the following best explains why noble gases are generally unreactive?

Accepted Answer

They have a full valence electron shell.

General Chemistry Exam 1 Study Guide: Matter, Measurement, Atoms, and Periodic Properties

Guida di studio - Domande di pratica

Study guide - Flashcard