Question 1

A hospital uses a saline solution made by dissolving 9.00 grams of NaCl in enough water to make 1.00 L of solution. What is the molarity of the solution? ($$	ext{Molar mass of NaCl} = 58.44\ 	ext{g/mol})$$

Accepted Answer

$$0.154\ 	ext{M}$$

Question 2

Which of the following processes is endothermic?

Accepted Answer

Vaporization

Question 3

A student needs to prepare 250 mL of 0.0500 M HCl solution from a stock solution of 1.00 M HCl. What volume of the stock solution should be used?

Accepted Answer

$$12.5\ 	ext{mL}$$

Question 4

Which statement about dynamic equilibrium in the process of vaporization is FALSE?

Accepted Answer

No molecules are escaping into the gas phase.

Question 5

Caffeine has the formula $$\mathrm{C}_8\mathrm{H}_{10}\mathrm{N}_4\mathrm{O}_2. $$What mass of caffeine contains 15.0 grams of carbon?

Accepted Answer

$$42.9\ 	ext{g caffeine}$$

Question 6

Which molecule below would have the highest boiling point?

Accepted Answer

$$\mathrm{CH}_3\mathrm{Cl}$$

Question 7

How many grams of oxygen are in 8.529 g of $$\mathrm{Na}_2\mathrm{CO}_3 (a $$common ingredient in baking soda)? ($$	ext{Molar mass of } \mathrm{Na}_2\mathrm{CO}_3 = 105.99\ 	ext{g/mol})$$

Accepted Answer

$$3.85\ 	ext{g}$$

Question 8

A compound with the empirical formula $$\mathrm{C}_2\mathrm{H}_4$$ has a molar mass of 56.0 g/mol. What is the molecular formula of the compound?

Accepted Answer

$$\mathrm{C}_4\mathrm{H}_8$$

Question 9

Which of the following contains the greatest number of molecules?

Accepted Answer

$$18\ 	ext{grams H}_2$$

Question 10

Rank the following molecules from highest to lowest surface tension: $$\mathrm{H}_2\mathrm{O}$$, $$\mathrm{CH}_3\mathrm{OH}$$, $$\mathrm{C}_6\mathrm{H}_6.$$

Accepted Answer

$$\mathrm{H}_2\mathrm{O} \u003e \mathrm{CH}_3\mathrm{OH} \u003e \mathrm{C}_6\mathrm{H}_6$$

Question 11

What is the hybridization of the iodine atom in the molecule $$\mathrm{IF}_4^-$$?

Accepted Answer

$$sp^3d^2$

Question 12

A sample of $$\mathrm{Na}_2\mathrm{SO}_4$$ solution is needed to make 1.50 L of 0.300 M solution. How many grams of $$\mathrm{Na}_2\mathrm{SO}_4$$ are required? ($$	ext{Molar mass of } \mathrm{Na}_2\mathrm{SO}_4 = 142.04\ 	ext{g/mol})$$

Accepted Answer

$$63.9\ 	ext{g}$$

Question 13

Which molecule below would have the highest melting point?

Accepted Answer

$$\mathrm{NaCl}$$

Question 14

What is the bond order of $$\mathrm{N}_2$$ according to molecular orbital theory?

Accepted Answer

$$3$$

Question 15

Consider the molecule $$\mathrm{BCl}_3. $$What is the steric number (SN) of the central atom? What is the electron geometry (EG) around the central atom? What is the hybridization of the central atom?

Accepted Answer

SN = 3, EG = trigonal planar, $$sp^2$$ hybridized

Question 16

A compound weighs 4.98 × $$10^{-23} g $$per molecule. The molecular formula of the compound is:

Accepted Answer

$$\mathrm{Cl}_2$$

Question 17

How much heat is required to boil 45.9 g of water? ($$\Delta H_{vap} of $$water = 44.01 kJ/mol)

Accepted Answer

$$112.3\ 	ext{kJ}$$

Question 18

How many sigma and pi bonds are present in the Lewis structure for $$\mathrm{CH}_3\mathrm{CHO}$$?

Accepted Answer

7 sigma bonds and 1 pi bond

Question 19

Which type of orbital is the lone pair on P occupying in the Lewis structure for $$\mathrm{PCl}_3$$?

Accepted Answer

$$sp^3$$

Question 20

Which of the following best represents the ground state in an energy diagram?

Accepted Answer

The lowest energy level

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