Question 1

Use the following figure to answer the questions below.
 
-How many grams of the compound in the figure above would be required to make 1 L of a 0.5 M solution?
(carbon = 12,oxygen = 16,hydrogen = 1)

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Question 2

Which of these molecules would be soluble in water?

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Question 3

How many grams of acetic acid (C₂H₄O₂)would you use to make 10 L of a 0.1 M aqueous solution of acetic acid? (Note: The atomic masses,in daltons,are approximately 12 for carbon,1 for hydrogen,and 16 for oxygen.)

Accepted Answer

The molar mass of acetic acid (C₂H₄O₂) is:

2(12.01 g/mol) + 4(1.01 g/mol) + 2(16.00 g/mol) = 60.05 g/mol

To make a 0.1 M solution of acetic acid, we need 0.1 moles per liter. For a 10 L solution, we would need:

0.1 mol/L x 10 L = 1 mol

So we need to use 1 mole of acetic acid, which is equal to:

1 mol x 60.05 g/mol = 60.05 g

Therefore, the answer is D)60 g.

Question 4

Use the following information to answer the questions below.
You live in Atlantic Canada and you are Skyping a friend in Manitoba.You are both complaining about the weather as both regions are being subjected to the same arctic air mass.As you discuss it,however,it becomes clear that she is experiencing a bitter cold that you are not.You realize that you had pretty much the same conversation last summer when it was much hotter in Manitoba than at home.
-The best explanation for this difference is that

Accepted Answer

The climate in Atlantic Canada is moderated by the Atlantic Ocean, which maintains more consistent temperatures throughout the seasons. Manitoba, being farther inland, experiences more extreme temperature fluctuations. Therefore, it is possible for Manitoba to experience more extreme heat in the summer and more extreme cold in the winter compared to Atlantic Canada.

Question 5

Measurements show that the pH of a particular lake is 4.0.What is the hydrogen ion concentration of the lake?

Accepted Answer

The pH of a solution is defined as the negative logarithm (base 10) of the hydrogen ion concentration. The formula to calculate hydrogen ion concentration (in moles per liter) is:
[H+] = 10^(-pH)
Substituting the given pH value of 4.0 in the above formula, we get:
[H+] = 10^(-4.0) = 0.0001 M = 10^(-4) M
Therefore, the best choice is C, which represents a hydrogen ion concentration of 10^-4 M.

Question 6

Use the following figure to answer the questions below.
 
-How many grams would be equal to 1 mol of the compound shown in the figure above?
(carbon = 12,oxygen = 16,hydrogen = 1)

Accepted Answer

From the figure, we can see that the compound has 2 carbon atoms, 6 hydrogen atoms, and 1 oxygen atom. The molar mass can be calculated as follows:
(2 x 12.01) + (6 x 1.01) + (1 x 16.00) = 30.08 g/mol

Therefore, 1 mol of the compound would weigh 30.08 grams, which is closest to choice C (60 grams).

Question 7

A small birthday candle is weighed,then lighted and placed beneath a metal can containing 100 mL of water.Careful records are kept as the temperature of the water rises.Data from this experiment are shown on the graph.What amount of heat energy is released in the burning of candle wax?

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Question 8

Measurements show that the pH of a particular lake is 4.0.What is the hydroxide ion concentration of the lake?

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Question 9

You have two beakers.One contains pure water; the other contains pure methanol (wood alcohol).The covalent bonds of methanol molecules are nonpolar,so there are no hydrogen bonds among methanol molecules.You pour crystals of table salt (NaCl)into each beaker.Predict what will happen.

Accepted Answer

NaCl is an ionic compound, meaning it is made up of charged particles. Water is a polar solvent, which means it has a partial positive charge on one end and a partial negative charge on the other. This allows it to interact with the charged particles in NaCl and dissolve it readily. Methanol, on the other hand, is a nonpolar solvent and cannot interact with the charged particles in NaCl. Therefore, NaCl crystals will not dissolve in methanol but will dissolve readily in water.

Question 10

Identical heat lamps are arranged to shine on identical containers of water and methanol (wood alcohol),so that each liquid absorbs the same amount of energy minute by minute.The covalent bonds of methanol molecules are nonpolar,so there are no hydrogen bonds among methanol molecules.Which of the following graphs correctly describes what will happen to the temperature of the water and the methanol?

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Question 11

You have two beakers.One contains a solution of HCl at pH = 1.0.The other contains a solution of NaOH at pH = 13.Into a third beaker,you slowly and cautiously pour 20 mL of the HCl and 20 mL of the NaOH.After complete stirring,the pH of the mixture will be

Accepted Answer

When we mix an acid and a base, they undergo a neutralization reaction, resulting in the formation of water and a salt. In this case, the acid is HCl and the base is NaOH.

HCl + NaOH → NaCl + H2O

Since HCl is a strong acid and NaOH is a strong base, the resulting solution will be neutral, with a pH of 7.0. Therefore, the correct answer is C) 7.0.

Question 12

-Based on your knowledge of the polarity of water molecules,the solute molecule depicted here is most likely

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-Based on your knowledge of the polarity...

Question 13

Carbon dioxide (CO₂)is readily soluble in water,according to the equation CO₂ + H₂O ↔ H₂CO₃.Carbonic acid (H₂CO₃)is a weak acid.If CO₂ is bubbled into a beaker containing pure,freshly distilled water,which of the following graphs correctly describes the results?

Accepted Answer

When CO2 is bubbled into water, it reacts with water to form carbonic acid (H2CO3), which is a weak acid. This reaction increases the concentration of H+ ions in the solution, making it slightly acidic. The graph should show a decrease in pH (more acidic) as more CO2 is bubbled into the solution. Choice B correctly shows the pH decreasing gradually as more CO2 is added. Choice A does not show a significant change in pH, while choices C, D, and E all show a sharp drop in pH that is not consistent with the gradual acidification caused by the weak acid H2CO3.

Question 14

Which of the following is a hydrophobic material?

Accepted Answer

Hydrophobic materials are non-polar and do not dissolve in water. Wax is a non-polar molecule and therefore is hydrophobic.

Question 15

A slice of pizza has 2092 kJ.If we could burn the pizza and use all the heat to warm a 50-L container of cold water,what would be the approximate increase in the temperature of the water? (Note: A litre of cold water weighs about 1 kg.)

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Question 16

Use the following figure to answer the questions below.
 
-How many grams of the compound in the figure above would be required to make 2.5 L of a 1 M solution?
(carbon = 12,oxygen = 16,hydrogen = 1)

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Question 17

We can be sure that a mole of table sugar and a mole of vitamin C are equal in their

Accepted Answer

A mole of any substance contains the same number of entities, which is Avogadro's number (6.022 x 10^23). Therefore, a mole of table sugar and a mole of vitamin C both contain the same number of molecules, making E the correct choice. The mass of each substance in grams will be different since they have different molar masses, making B incorrect. The volume of a substance depends on its density and is not necessarily the same for different substances, making C incorrect. The number of atoms in a substance will depend on its molecular formula and is not necessarily the same for different substances, making D incorrect. The term "mass in daltons" is synonymous with molar mass, making A redundant.

Question 18

The bonds that are broken when water vaporizes are

Accepted Answer

When water vaporizes, the hydrogen bonds between water molecules are broken. These bonds are a result of the polar covalent bond between oxygen and hydrogen within each water molecule, and the attraction between the partially negative oxygen of one molecule and the partially positive hydrogen of another molecule. While ionic bonds involve the transfer of electrons, water molecules do not involve ionization. Covalent bonds within a water molecule are not broken during vaporization. Neither polar nor nonpolar covalent bonds explain the breaking of hydrogen bonds during vaporization.

Question 19

Many mammals control their body temperature by sweating.Which property of water is most directly responsible for the ability of sweat to lower body temperature?

Accepted Answer

This choice refers to the heat of vaporization of water, which is high due to the breaking of hydrogen bonds. When sweat evaporates off the skin, it absorbs heat from the body and cools it down. This cooling effect is directly related to the absorption of heat by the breaking of hydrogen bonds.

Question 20

Use the following information to answer the questions below.
You live in Atlantic Canada and you are Skyping a friend in Manitoba.You are both complaining about the weather as both regions are being subjected to the same arctic air mass.As you discuss it,however,it becomes clear that she is experiencing a bitter cold that you are not.You realize that you had pretty much the same conversation last summer when it was much hotter in Manitoba than at home.
-This phenomenon is due to

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Quiz 3: Water and Life

Use the following figure to answer the questions below. -How many grams of the compound in the figure above would be required to make 1 L of a 0.5 M solution? (carbon = 12,oxygen = 16,hydrogen = 1)

Which of these molecules would be soluble in water?

How many grams of acetic acid (C₂H₄O₂) would you use to make 10 L of a 0.1 M aqueous solution of acetic acid? (Note: The atomic masses,in daltons,are approximately 12 for carbon,1 for hydrogen,and 16 for oxygen.)