$$M = \frac{\text{moles of solute}}{\text{volume of solution in liters}}$$

Question 1

Which of the following elements has the greatest number of valence electrons in its ground state?

Accepted Answer

Phosphorus ($$Z=15)$$

Question 2

What is the correct Lewis structure for the nitrate ion ($$NO_3$$^-$$)?

Accepted Answer

One double bond and two single bonds between N and O, with resonance among the oxygens.

Question 3

Which molecule has a trigonal planar molecular geometry according to VSEPR theory?

Accepted Answer

Boron trifluoride ($$BF_3)$$

Question 4

A student mixes solutions of $$AgNO_3$$ and $$NaCl. $$What type of reaction occurs and what is the precipitate formed?

Accepted Answer

Precipitation reaction; $$AgCl$$ precipitate

Question 5

Which of the following is the correct formula to calculate the molarity ($$M) of a $$solution?

Accepted Answer

$$M = \frac{	ext{moles of solute}}{	ext{volume of solution in liters}}$$

Question 6

Which of the following best describes the difference between ionic and covalent molecules?

Accepted Answer

Ionic molecules transfer electrons; covalent molecules share electrons.

Question 7

What is the oxidation state of sulfur in $$H_2SO_4$$?

Accepted Answer

+6

Question 8

Calculate the number of moles in 18 grams of water ($$H_2O$$). ($$M_{H_2O} = 18 	ext{ g/mol})$$

Accepted Answer

$$1$$ mole

Question 9

Which of the following acids is correctly named?

Accepted Answer

$$HCl - $$Hydrochloric acid

Question 10

A solution contains $$0.5$$ moles of $$NaCl$$ dissolved in $$250 mL of $$water. What is the molarity of the solution?

Accepted Answer

$$2.0 M$$

Question 11

Which of the following best explains why $$CO_2 is a $$nonpolar molecule despite having polar bonds?

Accepted Answer

The linear geometry causes the bond dipoles to cancel each other.

Question 12

What is the electron geometry of $$NH_3$$ according to VSEPR theory?

Accepted Answer

Tetrahedral

Question 13

Which of the following is a correct balanced equation for the precipitation reaction between $$Pb(NO_3$)_2$$ and $$KI$$?

Accepted Answer

$$Pb(NO_3$)_2 + 2KI \rightarrow $$PbI_2$$ + 2KNO_3$$

Question 14

Which subatomic particle is responsible for chemical bonding?

Accepted Answer

Electron

Question 15

A sample contains $$3.01 	imes 10$$^{23}$$ molecules of O_2$. How many moles of O_2$ are present?

Accepted Answer

$$0.5$$ moles

Question 16

Which of the following molecules has a bent molecular geometry?

Accepted Answer

$$H_2O$$

Question 17

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 18

Which of the following is a correct net ionic equation for the reaction between $$Na_2SO_4$$ and $$BaCl_2$$?

Accepted Answer

$$Ba^{2+} (aq$$) + $$SO_4$$^{2-} (aq) \rightarrow $$BaSO_4 (s$$)$$

Question 19

A student needs to prepare $$500 mL of$$ $$0.2 M$$ $$NaOH$$ solution. How many grams of $$NaOH$$ are required? ($$M_{NaOH} = 40 	ext{ g/mol})$$

Accepted Answer

$$4 g$$

Question 20

Which of the following statements about acids is correct?

Accepted Answer

Acids donate $$H^+$$ ions in solution.

General Chemistry I: Exam V Study Guide – Lewis Structures, VSEPR, and Foundational Concepts

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