$$0.500 \times 6.022 \times 10$$^{23}$$ = 3.01 \times 10$$^{23}$$ molecules

Question 1

Which of the following best describes a homogeneous mixture?

Accepted Answer

A mixture with a uniform composition throughout, such as saltwater.

Question 2

Which of the following is an example of a chemical change?

Accepted Answer

Burning wood in a campfire.

Question 3

A student measures the mass of a sample three times and gets values very close to each other, but far from the true value. This is an example of:

Accepted Answer

Low accuracy, high precision

Question 4

Which of the following is an intensive property?

Accepted Answer

Density

Question 5

What is the density of a metal sample with a mass of 50.0 g and a volume of 10.0 mL?

Accepted Answer

$$d = \frac{50.0\ g}{10.0\ mL} = 5.00\ g/mL$$

Question 6

Which of the following statements about Dalton’s atomic theory is still considered true today?

Accepted Answer

Atoms of different elements combine in simple whole-number ratios to form compounds.

Question 7

How many significant figures are in the measurement 0.00420 g?

Accepted Answer

3

Question 8

Convert 25.0 °C to Kelvin.

Accepted Answer

$$K = 25.0 + 273.15 = 298.15\ K$$

Question 9

Which of the following is a correct nuclide symbol for an isotope of carbon with 7 neutrons?

Accepted Answer

$$^{13}_{6}C$$

Question 10

Which of the following ions is isoelectronic with neon (Ne)?

Accepted Answer

$$Na^+$$

Question 11

What is the empirical formula for a compound containing 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mass?

Accepted Answer

$$CH_2O$$

Question 12

Which of the following best describes the trend in atomic radius across a period from left to right?

Accepted Answer

Atomic radius decreases due to increasing effective nuclear charge.

Question 13

Which of the following compounds is an example of a molecular compound?

Accepted Answer

$$CO_2$$

Question 14

What is the correct name for $$FeCl_3$$?

Accepted Answer

Iron(III) chloride

Question 15

Which of the following is the correct electron configuration for a neutral chlorine atom (Z = 17)?

Accepted Answer

$$1s^2$$ $$2s^2$$ $$2p^6$$ $$3s^2$$ $$3p^5$$

Question 16

Which of the following molecules has a trigonal planar geometry according to VSEPR theory?

Accepted Answer

$$BF_3$$

Question 17

Which of the following statements about sigma ($$\sigma) $$and pi ($$\pi) $$bonds is correct?

Accepted Answer

A double bond consists of one $$\sigma$$ bond and one $$\pi$$ bond.

Question 18

Which of the following is the correct formula for magnesium nitride?

Accepted Answer

$$Mg_3N_2$$

Question 19

Which of the following best describes the process of sublimation?

Accepted Answer

A solid changing directly to a gas without passing through the liquid state.

Question 20

A sample contains 0.500 mol of $$CO_2. $$How many molecules of $$CO_2$$ are present?

Accepted Answer

$$0.500 	imes 6.022 	imes 10$$^{23}$$ = 3.01 	imes 10$$^{23}$$ molecules

Matter and Measurement: Foundations of General Chemistry

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