Chapter 3

A slice of pizza has 500 kcal. 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 liter of cold water weighs about 1 kg.)

10 degrees c

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

10-10 M

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

10-4 M

A pH of 3 is how many times more acidic than a pH of 5

100

A solution at pH 6 contains __________ than the same amount of solution at pH 8.

100x more H+

A glass of grapefruit juice, at pH 3, contains __________ H+ as a glass of tomato juice, at pH 4.

10x as much

If the pOH value is 12, what is the pH value

2

Each water molecule is capable of forming _____ hydrogen bonds with adjacent water molecules

4

What is the heat of vaporization for water in calories per gram at room temperature

580

What is the pH of blood?

7.4

What do cohesion, surface tension, and adhesion have in common with reference to water?

All are properties related to hydrogen bonding.

How does the polarity of water contribute to its ability to dissolve so many substances?

Because it is polar, water's negatively charged oxygen atoms and positively charged hydrogen atoms are attracted to positively and negatively charged ions and molecules.

Which of the following dissociations is that of an acid? a. H2O → H+ + OH- b. NaOH → Na+ + OH- c. HF → H+ + F- d. NH3 + H+ → NH4+

HF → H+ + F-

What accurately relates the emergent properties of water to the effects of global warming in the Arctic?

Ice floats because it is less dense than liquid water; floating ice insulates water below and provides a habitat for some species. The significant increase in Arctic air temperature over the past 50 years is causing a reduction in sea ice, compromising these beneficial effects of sea ice.

Why are cell membranes composed primarily of hydrophobic molecules?

In order to perform their function of separating the aqueous solutions outside of cells from the aqueous solutions inside of cells, cell membranes cannot be soluble in water.

An acid is __________.

a compound that donates hydrogen ions to a solution

Water has __________ than other liquids such as ethanol , reflecting its capacity to absorb large amounts of heat.

a higher boiling point

Heat is _______ when hydrogen bonds break

absorbed

The property of water that contributes to its ability it to stick to certain surfaces is called

adhesion

Adding a base tends to __________ of a solution.

lower the hydrogen ion concentration and increase the pH

A mole of ethyl alcohol weighs 46 g. How many grams of ethyl alcohol are needed to produce 1 L of a 2-millimolar (2 mM) solution?

0.092 g

Why is the increasing amount of carbon dioxide being taken up by the oceans a cause for concern?

More carbon dioxide causes an increase in carbonic acid (H2CO3), which leads to a decrease in the concentration of carbonate ion (CO32-).

How do you correctly spell Mrs. Niemo's last name

Niemantsverdriet

Imagine that organisms consisted of 70-95% alcohol instead of 70-95% water. Alcohol's specific heat is about half that of water. How would living things be different?

Systems for temperature regulation would have to be much more efficient. - In order for living things to inhabit a wide range of environments, temperature regulation would need to be more efficient for a fluid with a lower specific heat

If water were NOT a polar molecule, how would the effects of global warming differ from those currently observed or predicted to occur in the future?

The effects would be drastically worse because the loss of the polar nature of water would greatly reduce its specific heat and its ability to moderate temperature.

What do water's cohesion, surface tension, and adhesion all have in common?

are related to hydrogen bonding

A pH of 7.12 is

basic

The ability of water molecules to form hydrogen bonds with other water molecules and water's ability to dissolve substances that have charges or partial charges are __________.

both caused by water's partial charges

A substance that minimizes changes in the concentration of H+ and OH- in a solution is a __________.

buffer

The phenomenon responsible for maintaining the upward movement of water through vessels in a tree is _________

cohesion

Which action would involve the greatest transfer of heat? a. cooling 10 g of water from 80°C to 40°C b. changing the temperature of 1 g of water from 10°C to 90°C c. condensing 5 g of steam to liquid water d. evaporating 1 g of water at 25°C

condensing 5 g of steam to liquid water - This would release about 2,900 calories (580 calories/gram × 5 grams)

Cells are surrounded by water, and cells themselves consist of about 70-95% water. Which of the following occurs as a result? a. Waste products produced by cell metabolism can be easily removed. b. A variety of nutrient molecules is readily available as dissolved solutes. c. The temperature of living things tends to change relatively slowly. d. All of the listed responses are correct.

d

Utilization of water to prevent overheating is called

evaporative cooling

Sweating has a cooling effect because of water's high __________.

heat of vaporization - Water's high heat of vaporization results in evaporative cooling because when water evaporates, the surface on which it rests cools down.

What property of water allows it to have a very high boiling point

hydrogen bonds

What property of water allows it to have a very high boiling point?

hydrogen bonds

What are nonpolar molecules that cluster away from water molecules called?

hydrophobic

A molecule that has all nonpolar covalent bonds would be __________.

hydrophobic - For example, the hydrophobic behavior of oil molecules results from a prevalence of nonpolar covalent bonds. Nonpolar molecules do not have an affinity for water or other polar molecules.

What occurs because molecules of water are farther apart in ice than in liquid water?

ice floats

Adding acid tends to __________ of a solution.

increase the hydrogen ion concentration and lower the pH

The absorption of human-generated CO2 by the oceans __________.

increases the hydrogen ion concentration in the oceans but decreases the carbonate ion concentration and threatens the livability of the oceans for organisms that produce calcium carbonate shells

The tendency of water molecules to stay close to each other as a result of hydrogen bonding __________.

is called cohesion, acts to moderate temperature, provides the surface tension that allows small animals to move across a water surface, and helps to keep water moving through the vessels in a tree trunk

Which of the following would most likely form a colloid when mixed with water

large hydrophilic protein

Water's ability to create intermolecular hydrogen bonds results in its inability to break up

lipids

Which of the following is not an important characteristic of water a. low boiling point b. cohesion c. high specific heat d. polarity

low boiling point

Water is a very versatile solvent because water molecules are __________.

polar

What type of bonds are found within a water molecule

polar covalent

Hydrogen bonding between water molecules is due mainly to water's

polar covalent bonds

To make a 1M solution you should

put a mole of the substance in a container and fill to 1L

Water surrounding a substance forms a hydration

shell

The reason that coastal climates are more moderate than inland climates primarily water's high __________.

specific heat

Water is slow to change temperature, thus it has a high

specific heat

Sucrose has a molecular mass of 342 daltons. To make a 2-molar (2 M) solution of sucrose, __________.

stir 342 g of sucrose in water to dissolve the sugar, and then add enough water to bring the total volume of the solution up to 0.5 L - Or you could stir 684 g of sucrose in water to dissolve the sugar, and then add enough water to bring the total volume of the solution up to 1 L.

You can fill a glass of water to just slightly above the rim without the water spilling over the glass. What property of water best explains this phenomenon?

surface tension

Water is a polar molecule. What does this statement mean?

that atoms in the molecule have partial charges as a result of unequal sharing of electrons in a covalent bond

Electronegativity is

the attraction of an atom for the electrons in a covalent bond

Adhesion is best described as which of the following?

the clinging of one substance to another substance

The amount of heat required to convert 1 g of any substance from the liquid to the gaseous state is defined as __________.

the heat of vaporization of that substance

The amount of heat required to change the temperature of 1 g of any substance by 1°C is defined as __________.

the specific heat of that substance - The specific heat of a substance is defined as the amount of heat that must be absorbed or lost to change the temperature of 1 g of that substance by 1°C.

The partial charges on a water molecule occur because of __________.

the unequal sharing of electrons between the hydrogen and the oxygen atoms of a water molecule

A polar covalent bond between two atoms results from

two atoms that do not have similar electronegativities