chem 1100 cht. 5

Which of the following values correspond to densities? (Select all that apply.)

- 45 g/mL - 29 kg/L

Which of the following options correctly describe molecular polarity? Select all that apply.

- A molecule that contains only nonpolar bonds is nonpolar. - Overall molecular polarity depends on the geometry of a molecule. - A molecule that contains polar and nonpolar covalent bonds could be polar or nonpolar.

Which of the following statements correctly define an aqueous solution? Select all that apply.

- An aqueous solution can have one or more solutes. - An aqueous solution is a homogeneous mixture. - Water is always the solvent in an aqueous solution.

Which of the following options correctly describe the water cycle? Select all that apply.

- Climate can affect the water cycle. - A drop of water in the ocean could one day end up in a lake.

Which of the following options correctly describe the effects of climate change on the water cycle and events in ecosystems? Select all that apply.

- Climate change can affect the amount of available fresh water. - Climate change can affect the timing of events in ecosystems. - Higher temperatures during the winter months can cause glaciers to recede.

Which of the following options correctly describe the different sources of fresh water? Select all that apply.

- Groundwater is found in aquifers. - Sea water can be used as a source of water. - Surface water is found in lakes, streams, and rivers.

Which of the following molecules would exhibit hydrogen bonding? (Select all that apply.)

- HF - NH3

Which of the following species will be present in an aqueous solution of Na2CO3?

- Na+ - CO32-

Which of the following bodies of water is/are included in the natural water cycle? Select all that apply.

- Sea ice - Glaciers - Lakes - Rivers

Which of the following statements correctly describe surfactants? Select all that apply.

- Soaps and detergents are examples of surfactants. - Surfactants contain polar groups. - Surfactants contain nonpolar groups.

Which of the following statements correctly describe the illustration? (Select all that apply.)

- The atoms involved in interaction A are farther apart than the atoms involved in interaction B. - Interaction A is an example of an intermolecular force.

Which of the following options correctly describe electronegativity and its trends? Select all that apply.

- The higher the electronegativity value of an element, the more strongly it attracts bonding electrons to itself. - Electronegativity increases from left to right in the periodic table. - The element with the highest electronegativity is fluorine.

Which of the following options correctly describe and interpret the illustration? (Select all that apply.)

- The illustration depicts a polar covalent bond. - The electrons in the O-H bond are closer to O, giving it a partial negative charge.

Which of the following properties are unusual or unique properties of water? Select all that apply.

- Water is a liquid at room temperature and normal atmospheric pressure. - All three phases of water are commonly found on Earth.

When an ionic compound is added to water, the ______ will be attracted to the partially positive H atom of water and the _____ will be attracted to the partially negative O atom of water. As the compound dissolves the ions will _____ or separate from each other.

- anions - cations - dissociate

If the sign δ- is used to mark an atom in a covalent bond, it means that _____. (Select all the options that complete the sentence correctly.)

- this atom has a higher electron density - this atom has a partial negative charge - this atom is more electronegative

The standard temperature and pressure for reporting properties such as density are _____ and _______.

1 atm 25°C

Rank the following commodities according to the size of their water footprints, placing the commodity that has the smallest water footprint at the bottom of the list.

1. 1 cotton t-shirt 2.1 chocolate bar 3. 1 glass of orange juice 4. 1 cup of tea

Which of the following options correctly describe the use of distillation as a desalination technique? Select all that apply.

1. A new heating source used for distillation is solar power 2. It requires a lot of energy to desalinate water by distillation 3. MSF distillation technique is a modern technique used on large scale

Rank the following bonds from the most to the least polar, starting with the most polar bond at the top of list.

1. H-F 2. P-O 3.C-O 4.C-H

Rank the following meats from highest to lowest water footprint. Place the meat with the largest water footprint at the top.

1. beef 2. sheep 3. pork 4. chicken

Arrange the phases of water from the least dense to the most dense, starting with the least dense phase at the top of the list.

1. gas 2. solid 3. liquid

Rank the following compounds, from lowest to highest boiling points. For your ranking, place the lowest-boiling compound on the top.

1.HCl 2.HBr 3HI

Which of the following statements correctly describe the process by which an ionic compound dissolves in water? Select all that apply.

1.The positive and negative ions dissociate from each other. 2. The positive ions are attracted to the partially negative O atom of the H2O. 5. The attraction between the H2O molecules and the ions is stronger than the attraction of the ions for each other.

Approximately how many people on the Earth lack access to clean drinking water?

2,100,000,000

Calculate the density of a sugar cube that has a mass of 15.5 g and sides 1.8 cm in length.

2.65 g/cm3

How much energy must be absorbed by 10 g of water to increase its temperature by 5 ∘C?

209 J

What percentage of water on Earth is fresh water?

3%

If the density of ice is 0.92 g/cm3, what is its density in units of g/L?

920 g/L

Match the percentages of Earth's water and fresh water with the appropriate water source.

97% - Oceans 3% - Fresh water 68% - Glaciers, ice caps and snowfields 30% - Aquifers 1% - Atmosphere 0.3% - Lakes, swamps, rivers

According to the World Health Organization estimates, approximately how many infants and children die each day due to contaminated water?

> 3000

Match each process or reagent in the treatment of water with the appropriate letter on the illustration. Instructions

A-Flocculating agents B-Flocculator C-Charcoal and sand filter D-Chlorination E-Fluoridation

Which of the following applications utilizes the most water on a global scale?

Agriculture

Match each set of reagents used in the water treatment process with their purpose. Instructions

Al2(SO4)3 and Ca(OH)2 - flocculating agents Cl2, NaClO, or Ca(ClO)2 - antibacterial agents F- - prevents tooth decay

What are the consequences of a large amount of phosphates and nitrates in the water? Select all that apply.

Algal blooms Oxygen depletion Dead fish

A(n) _____ is a source of freshwater located underground.

Aquifers

Naturally occurring underground reservoirs containing fresh water are called _____.

Aquifers

What is the shape of a water molecule?

Bent

Which of the following molecules is nonpolar?

CO2

What technique is being applied in this illustration?

Distillation

What are methods used to remove ions from salt water?

Distillation Reverse osmosis Desalination

The ability of a covalently bonded atom to attract the shared electrons is called .

Electronegativity

The sewage treatment process is very similar to the water treatment process, except for a couple of steps. Which step in the illustration is omitted in the sewage treatment process?

F

True or false: All ionic compounds are highly soluble in water.

FALSE

True or false: A bond between O and H within any molecule is called a hydrogen bond.

False

Which of the following is the correct condensed molecular formula for water?

H2O

Which of the following is the strongest type of intermolecular force?

Hydrogen bonds

A(n) _______ force or attraction is an attraction that occurs between molecules.

Intermolecular

Which of the following balanced equations correctly represents the dissociation of K2SO4 in water?

K2SO4 (s) → 2K+ (aq) + SO42- (aq)

Which of the following solvents would be best to dissolve pentane, a nonpolar hydrocarbon molecule?

Liquid carbon dioxide

Which of the following compounds would have the highest boiling point?

NH3

Which of the following molecules is polar?

NH3

Match each bond with the appropriate difference in electronegativity.

O-H; 1.4 F-H; 1.9 S-CL; 0.5 Si-F; 2.2

Which of the following gives the best explanation for why oil and water do not mix?

Oil does not mix with water because the two substances do not react with each other.

What waste is present in sewage that makes it more complicated to treat than contaminants found in water in the water treatment process? Select all that apply.

Organic compounds Nitrate ions

Which of the following are alternative disinfectants to chlorine-containing compounds used in water treatment? Select all that apply.

Ozone (O3) UV radiation

The abbreviation STP indicates standard

Standard Temperature and Pressure

True or false: Glaciers contribute to the distribution of fresh water on Earth.

TRUE

True or false: Water and ethanol will mix, since they are both polar.

TRUE

Which of the following options correctly describes the changes that occur when a polar covalent substance such as glucose (C6H12O6) dissolves in water?

The polar glucose molecules are attracted to the polar water molecules, resulting in a solution

Which type of water use has experienced the greatest decrease from 2005 to 2015?

Thermoelectric power

Which of the following methods is being used by some sewage treatment plants to decrease the effect of releasing phosphates and nitrates into surface water?

Using wetland areas to capture nitrates and phosphates before the water is returned to the surface water.

What is potable water?

Water that is safe to drink and to cook with

when an ionic compound is added to water, the ____ will be attracted to the partially positive H atom of water and the _____ will be attracted to the partially negative O atom of water. as the compound dissolves the ions separate from each other, or _______

anion ; cation ; dissociate

A(N) ______ solution is one in which water is the solvent.

aqueous

A person who is concerned with the sustainable use of water would want to eat less ______ since it has the highest water footprint.

beef

Fresh water found in an aquifer is located:

below ground (groundwater)

Both ozone (O3) and UV radiation have been used as alternative disinfectants to chlorine-containing compounds in the water treatment process. However, _____ must be added to the water after either of these treatment methods in order to protect the water after it leaves the treatment site.

chlorine

True or false: A chocolate bar has a greater water footprint than a cotton T-shirt.

false

True or false: The boiling point of H2S would be higher than H2O due to stronger intermolecular forces.

false

A water ______ is an estimate (for an individual or nation) of the amount of water required to sustain the consumption of goods and services.

footprint

A low BOD is an indication of _____ quality water.

good

Water has many unique properties. These anomalies include a _____ boiling point and a tendency to _____ on freezing.

high; expand

Unlike most substances, ice floats on liquid water. This is due to _____.

hydrogen bonding

All _____ bonds are much weaker than _____ bonds.

hydrogen bonds; covalent

In general, for molecular compounds of similar type, as the molar mass _____ the boiling point increases.

increase

The attraction indicated by the arrow in the illustration is a(n) _____.

intermolecular force

The density of ice is _____ than liquid water. However, for most substances, the density of its solid state is usually _____ than its liquid state.

less, more

One water molecule can hydrogen bond to four other water molecules giving its solid phase hexagonal channels. As a result, the molecules in the solid state are ______ closely packed than in the liquid state and solid water is therefore ______ dense than liquid water.

less; less

When hydrogen is covalently bonded to Blank _______ , Correct Unavailable, oxygen, or fluorine there will be an attraction between such a hydrogen and a lone pair of electrons on one of the aforementioned atoms on an adjacent molecule or in a different part of the same molecule. This attraction is called a(n) _______ , Correct Unavailable bond and it is the strongest

nitrogen or N, H or hydrogen

Match each term with the appropriate definition. Instructions

osmosis-The passage of water through a semipermeable membrane from a solution that is less concentrated to a solution that is more concentrated reverse osmosis-Employing the use of pressure to force the movement of water through a semipermeable membrane from a solution that is more concentrated to one that is less concentrated

BOD is a measure of the amount of dissolved _____ microorganisms use up as they decompose organic wastes found in water.

oxygen

In a(n) _____ bond electrons are not shared equally, but are closer to the more electronegative atom.

polar covalent

In general, covalent compounds that are _____ will be soluable in water. These compounds do not _____ into ions and are therefore nonelectrolytes.

polar, dissociate

The general solubility rule "like dissolves like" explains why polar solutes are soluble in ______ solvents and nonpolar solutes are soluble in ______ solvents.

polar; nonpolar

Water that is safe to drink and to cook with is called _______ water

potable

The chlorine-containing chemicals (HClO, ClO-, and Cl2) that remain in the water after the chlorination step in the water treatment process are called _____ chlorine.

residual

The quantity of heat energy that must be absorbed to increase the temperature of 1 gram of a substance by 1°C is called its _____.

specific heat

A(n) ______, also sometimes called a wetting agent, is a compound that helps polar and nonpolar compounds mix.

surfactants

An estimate of the water used to produce a particular product is known as a _______.

water footprint

An ionic compound will produce an aqueous solution when the attraction between the _____ molecules and the ions is greater than the attraction between the ______ themselves. Ion size and charge can also play a role in the solubility of ionic compounds.

water, ions

Match the symbols correctly to describe the uneven charge distribution in any polar covalent bond.

δ+; marks the atom with the LOWER electronegativity marks the atom with the lower electronegativity δ-; marks the atom with the HIGHER electronegativity marks the atom with the higher electronegativity

Which of the following statements correctly describe reverse osmosis? Select all that apply.

-Most desalination plants utilize reverse osmosis. -Reverse osmosis utilizes pressure to move water.

Which techniques are used to desalinate water? Select all that apply.

-Reverse osmosis - Distillation

Which of the following statements describe the drawbacks of using chlorine-containing chemicals in the water treatment process? Select all that apply.

-The taste and odor of residual chlorine is objectionable. -Chlorine-containing chemicals can themselves be toxic. -Chlorine can react with organic matter to form trihalomethanes (THMs).