Q: Convert 0.250 kilometers to centimeters. (Use $$1 \mathrm{km} = 1000 \mathrm{m}$$ and $$1 \mathrm{m} = 100 \mathrm{cm})$$

$$0.250 \times 1000 \times 100 = 25,000 cm$$

Question 1

Which of the following statements best distinguishes a compound from a mixture?

Accepted Answer

A compound consists of two or more elements chemically bonded in fixed proportions, while a mixture contains substances physically combined in variable proportions.

Question 2

Which of the following is a physical change?

Accepted Answer

Dissolving table salt in water.

Question 3

Which group on the periodic table contains the noble gases, and what is a key property of these elements?

Accepted Answer

Group 18; they are chemically inert due to a full valence shell.

Question 4

A student measures the mass of a sample as 0.00560 kg. How many significant figures are in this measurement?

Accepted Answer

4

Question 5

Convert 0.250 kilometers to centimeters. (Use $$1 \mathrm{km} = 1000 \mathrm{m}$$ and $$1 \mathrm{m} = 100 \mathrm{cm})$$

Accepted Answer

$$0.250 	imes 1000 	imes 100 = 25,000 cm$$

Question 6

Which of the following elements is a metalloid?

Accepted Answer

Silicon (Si)

Question 7

What is the mass number of an atom with 20 protons, 22 neutrons, and 20 electrons?

Accepted Answer

$$20 + 22 = 42$$

Question 8

Which of the following ions is a polyatomic ion and has a negative charge?

Accepted Answer

$$\mathrm{SO}_4$$^{2-}$$ (sulfate)

Question 9

Which electron configuration represents a neutral atom of phosphorus ($$Z=15$$)?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^6$$\ $$3s^2$$\ $$3p^3$$

Question 10

Which of the following molecules is linear in shape according to VSEPR theory?

Accepted Answer

$$\mathrm{CO}_2$$

Question 11

Which of the following elements is most likely to form a diatomic molecule in its natural state?

Accepted Answer

Nitrogen (N)

Question 12

What is the charge on the phosphate ion ($$\mathrm{PO}_4$$)?

Accepted Answer

$$3-$$

Question 13

Which of the following compounds will form hydrogen bonds?

Accepted Answer

$$\mathrm{NH}_3$$

Question 14

Which of the following is the correct Lewis structure for water ($$\mathrm{H}_2\mathrm{O}$$)?

Accepted Answer

O atom with two single bonds to H atoms and two lone pairs on O

Question 15

Which of the following best describes electronegativity?

Accepted Answer

The ability of an atom to attract electrons in a chemical bond.

Question 16

Which of the following is a correct statement about the periodic table?

Accepted Answer

Elements in the same group have similar chemical properties.

Question 17

A molecule has three electron groups and one lone pair on the central atom. What is its molecular geometry?

Accepted Answer

Bent

Question 18

Which of the following compounds is ionic?

Accepted Answer

$$\mathrm{NaCl}$$

Question 19

Which of the following is the correct scientific notation for 0.00056?

Accepted Answer

$$5.6 	imes 10$$^{-4}$$

Question 20

Which of the following molecules is polar and has a tetrahedral electron geometry?

Accepted Answer

$$\mathrm{NH}_3$$

General Chemistry Exam 1 Comprehensive Study Guide

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