Question 1

Which of the following best describes the shape of the ammonia (NH$_3$) molecule according to its Lewis structure and VSEPR theory?

Accepted Answer

Trigonal pyramidal

Question 2

How many valence electrons are present in the sulfate ion (SO$_4^{2-}$)?

Accepted Answer

32

Question 3

Which of the following is the correct balanced chemical equation for the combustion of methane (CH$_4$) in oxygen?

Accepted Answer

$\mathrm{CH_4 + 2O_2 \rightarrow CO_2 + 2H_2O}$

Question 4

Given the Lewis structure for carbon dioxide (CO$_2$), what is its molecular shape?

Accepted Answer

Linear

Question 5

Which of the following is a correct balanced equation for the decomposition of hydrogen peroxide (H$_2$O$_2$)?

Accepted Answer

$\mathrm{2H_2O_2 \rightarrow 2H_2O + O_2}$

Question 6

A student determines the molar mass of an unknown compound by measuring 0.500 g of the compound and finding it produces 0.250 mol of gas at STP. What is the molar mass of the compound?

Accepted Answer

$2.00\ \mathrm{g/mol}$

Question 7

Which of the following is a single displacement reaction?

Accepted Answer

$\mathrm{Zn + 2HCl \rightarrow ZnCl_2 + H_2}$

Question 8

What is the total number of valence electrons in the nitrate ion (NO$_3^-$)?

Accepted Answer

24

Question 9

Which of the following word equations represents a combination reaction?

Accepted Answer

Hydrogen gas reacts with oxygen gas to form water.

Question 10

Which of the following is the correct Lewis structure description and shape for water (H$_2$O)?

Accepted Answer

Two single bonds, two lone pairs on oxygen; bent shape

Question 11

A student mixes copper(II) sulfate solution with iron metal. Which type of reaction occurs and what is the balanced equation?

Accepted Answer

Single displacement; $\mathrm{Fe + CuSO_4 \rightarrow FeSO_4 + Cu}$

Question 12

Which of the following is the correct balanced equation for the decomposition of calcium carbonate (CaCO$_3$)?

Accepted Answer

$\mathrm{CaCO_3 \rightarrow CaO + CO_2}$

Question 13

Which molecule has a tetrahedral shape according to its Lewis structure and VSEPR theory?

Accepted Answer

Methane (CH$_4$)

Question 14

A student is given 1.00 g of an unknown gas and collects 0.025 mol at STP. What is the molar mass of the gas?

Accepted Answer

$40.0\ \mathrm{g/mol}$

Question 15

Which of the following is the correct balanced equation for the combination reaction between sodium and chlorine gas?

Accepted Answer

$\mathrm{2Na + Cl_2 \rightarrow 2NaCl}$

Question 16

Which of the following molecules has a trigonal planar shape?

Accepted Answer

Boron trifluoride (BF$_3$)

Question 17

Which of the following is a correct single displacement reaction?

Accepted Answer

$\mathrm{Mg + 2HCl \rightarrow MgCl_2 + H_2}$

Question 18

How many valence electrons are present in the phosphate ion (PO$_4^{3-}$)?

Accepted Answer

35

Question 19

Which of the following is the correct balanced equation for the combustion of propane (C$_3$H$_8$)?

Accepted Answer

$\mathrm{C_3H_8 + 5O_2 \rightarrow 3CO_2 + 4H_2O}$

Lab Exam 2 Study Guide: Chemical Reactions, Lewis Structures, and Molar Mass Determination

Study Guide - Practice Questions

Study Guide - Flashcards