CHM Ch. 5
Which of the following options correctly describe the water cycle? Select all that apply.
-A drop of water in the ocean could one day end up in a lake. -Climate can affect the water cycle.
Which of the following options correctly describe the behavior of acids? Select all that apply.
-An acid will cause the dye litmus to change from blue to pink. -Acids have a sour taste.
Which of the following would represent an example of a tragedy of the commons? (Select all that apply.)
-Dumping waste into a public lake -Overfishing a lake
Which of the following options correctly explain what is meant by the term "strong acid" in chemistry? Select all that apply.
-If a strong acid is dissolved in water there will be no undissociated acid molecules in solution. -A strong acid dissociates completely in aqueous solution.
Which of the following options correctly describe electronegativity and its trends? Select all that apply.
-The element with the highest electronegativity is fluorine. -Electronegativity increases from left to right in the periodic table. -The higher the electronegativity value of an element, the more strongly it attracts bonding electrons to itself.
What is the molarity of sodium chloride in a solution containing 0.50 mol of sodium chloride in 500 ml of water?
1.00 M
Every increase of one pH unit indicates
10 times less hydrogen ions in solution.
Evaluate the ratio MH+ (pH 3) / MH+ (pH 7).
10,000
Approximately how much water per day is required to support the lifestyle of the average U.S. citizen, according to the U.S. Geological Survey?
100 gallons
An aqueous solution has 124 g of a salt dissolved in 1000 g of solution. What is the concentration of the salt in units of %?
12.4%
Approximately how many people on the Earth lack access to clean drinking water?
2,100,000,000
What is the pH of a solution with a [H+] of 1.7 x 10^-3 M?
2.8
Which of the following is a characteristic reaction of acids?
Acids react with carbonates to produce carbon dioxide.
Which of the following is not carried out by bacteria in soil?
All of these are carried out by bacteria
What is the net ionic equation for the reaction of barium nitrate and copper(II) sulfate in aqueous solution?
Ba2+(aq) + SO42-(aq) --> BaSO4(s)
Which reaction represents an acid base neutralization reaction?
Be(OH)2 + H2SO4 → BeSO4 + 2H2O
What is the shape of a water molecule?
Bent
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.
Blank 1: anions, negative ions, anion, or negative ion Blank 2: cations, positive ions, cation, or positive ion Blank 3: dissociate
Which of the following substances is a weak base?
CH3NH2
Which of the following species will be present in an aqueous solution of Na2CO3?
CO32- Na+
Which best symbolized the hydrogen bonding between two water molecules?
Diagram
Which shows the Lewis structure of water with the correct partial charges and nonbonding electrons?
Diagram
Which of the following solvents would be best to dissolve pentane, a nonpolar hydrocarbon molecule?
Liquid carbon dioxide
Rank the following solutions in order of increasing concentration: a.) 32.3 g of NaCl in 100 mL of water b.) 0.10 mol of NaCl in 10 mL of water c.) 62.1 g of NaCl in 1 L of water d.) 0.25 M NaCl solution
NOT c < d < b < a
Which of the following molecules are polar?
Only H2O but it said wrong?
True or false: Water and ethanol will mix, since they are both polar.
True
A substance that releases H+ ions in water is called a(n) ______
acid
Which correctly describes groundwater?
any water taken from aquifers
A substance that releases OH- ions in water is called a(n) ________.
base
what atmospheric component is responsible for the natural acidity of rain?
carbon dioxide
Which type of water may be considered pure?
distilled water
A weak acid is also a weak ____.
electrolyte
A low BOD is an indication of _____ quality water.
good
One table sugar (sucrose, C 12 H 22 O11) dissolves in water which types of attraction between water and sugar molecules occur?
hydrogen bonding and polar-polar interactions
The species that forms when a proton associates with a molecule of H2O is known as the__________ ion.
hydronium
Acids produce this in water
hydronium ion
when the ______ molecules of ethanol, C2H5OH are added to water the ethanol molecules_______
polar; form hydrogen bonds with the polar water molecules
The general solubility rule "like dissolves like" explains why polar solutes are soluble in ______ solvents and nonpolar solutes are soluble in ______ solvents.
polar; nonpolar
The hydronium ion concentration in a solution with pH 10 is ________ than the hydronium ion concentration in a solution with pH 13.
1,000 times greater
Scientists predict that shells of some ocean creatures will start to dissolve after how many more years of ocean acidification?
40 years
How many liters of water can a single LifeStraw purify?
4000 L
20.0 g of NaOH is weighed and dissolved in enough water to prepare a 0.10 M solution. What size volumetric flask would be required for this solution?
5.0 L
An aqueous solution is composed of 5.7 g of NaCl in 100 g of solution. What is the concentration of the solution, in units of %?
5.7%
According to the World Health Organization estimates, approximately how many infants and children die each day due to contaminated water?
> 3000
According to the USGS, how much water per day is needed by the average U.S. citizen?
> 390 L
Which substance has the highest pH?
A lye solution
Which of the following gives the best explanation for why oil and water do not mix?
Oil does not mix with water because oil is nonpolar and water is polar
Which of the following statements correctly describe the process by which an ionic compound dissolves in water? Select all that apply.
-The positive ions are attracted to the partially negative O atom of the H2O. -The attraction between the H2O molecules and the ions is stronger than the attraction of the ions for each other. -The positive and negative ions dissociate from each other.
What is the molarity of a 1.50-L solution containing 22.3 g of sodium chloride (NaCl)? The molar mass of NaCl is 58.44 g/mol.
0.254 M
What is the concentration of hydroxide ions in an aqueous solution containing (H+) = 1 x 10 ^ -5 M?
1 x 10 ^ -9
What is the concentration of OH- ions in a solution that contains 1 × 10-3 M H+?
1 × 10-11 M
Which of the following options correctly defines an electrolyte?
A substance that conducts an electric current in aqueous solution
Which of the following reactions corresponds to the balanced reaction between calcium chloride and silver nitrate?
CaCl2(aq) + 2 AgNO3(aq) --> Ca(NO3)2(aq) + 2 AgCl(s)
The acid neutralizing capacity of a lake or stream most often derives from the presence of _____ in the surrounding soil or rock
CaCo3
Which reaction accounts for the fact that the pH of rain is naturally slightly acidic?
Co2+H20 = H+ + HCO3- (co2 is found in acid rain)
What are methods used to remove ions from salt water?
Distillation Desalination Reverse osmosis
Which techniques are used to desalinate water? Select all that apply.
Distillation Reverse osmosis
True or false: A chemical company inadvertently dumps toxic waste into a local river, which pollutes the water for residents of a nearby town. However, this is not considered a tragedy of the commons since the company did not do this intentionally.
False
An acid is a compound that releases _____ ions in aqueous solution.
H+
Which of the following species play a role in maintaining the normal pH of seawater? (Select all that apply.)
HCO3- CO32- H2CO3
Which reaction most accurately represents the dissociation of nitrous acid (HNO2) in water?
HNO2 + H2O → H3O+ + NO2¯
Which reaction most accurately represents the dissociation of nitrous acid (Hno2) in water?
HNO2 +H20 = H3O+ + No2- (remember to keep your nitrite as one thing)
Which of the following balanced equations correctly represents the dissociation of K2SO4 in water?
K2SO4 (s) → 2K+ (aq) + SO42- (aq)
Which of the following statements correctly describe LifeStraw? Choose all that apply.
LifeStraw is a pipe filter. LifeStraw removes most bacteria, viruses, and parasites from water.
Which solution is acidic?
MOH¯ = 1.77 × 10¯10 M
Unit of concentration. Moles/Liters of solution
Molarity
Which of the following ions always form soluble ionic compounds? (Select all that apply.)
NH4+ NO3- Na+
The release of _______ gas causes acid rain through formation of nitric acid, HNO3.
NO2
Which of the following gases produce acidic solutions in water? Select all that apply.
NO2 CO2 SO2
Match each ion to the correct description of its solubility when combined with an ion of opposite charge.
Na+=soluble in all combinations soluble in all combinations SO42-=soluble except with Sr2+, Ba2+, and Pb2+ soluble except with Sr2+, Ba2+, and Pb2+ CO32-=insoluble except with Group 1A cations or NH4+ insoluble except with Group 1A cations or NH4+ Cl-= soluble except with Ag+ and Hg22+ soluble except with Ag+ and Hg22+
mixing which of the following will produce a precipitation reaction? (given insoluble product)?
Na2SO4(aq) and Ba(OH)2 (aq)
Mixing which of the following will produce a precipitation reaction (give an insoluble product)
Na2So4 (aq) and Ba(OH)2 aq
A proton release by an acid in aqueous solution quickly reacts with water to form a hydronium ion. What product is formed when a proton reacts with ammonia (Nh3)
Nh 4+ ( add a Hydrogen and put the charge)
When the _____ molecules of ethanol, C2H5,OH are added to water the ethanol molecules
Polar: form hydrogen bond with the polar water molecules
We cannot effectively clean nonpolar substances from our hands or clothing with water alone; we must add soap or detergent. The structure of a typical soap molecule is shown below. Which region of this molecule will dissolve in a nonpolar substance such as grease?
Region 1
Which of the following gases cause acid rain? (Select all that apply.)
SO3 NO2
How does ocean acidification affect marine organisms such as coral?
The CaCO3 in coral dissolves to replace the CO32- ions used up by excess H+ ions.
Which of the following options correctly describe the pH scale? (Select all that apply.)
The more acidic a solution is, the lower its pH. A solution with a pH of 3.0 is more acidic than a solution with a pH of 5.0.
Which is the best definition of specific heat?
The quantity of heat energy that must be absorbed to increase the temperature of one gram of a substance one degree Celsius
A polar covalent bond is created when
Two atoms share their bonding electrons unequally
What is potable water?
Water that is safe to drink and to cook with
Match each H+ concentration to its corresponding OH- concentration in aqueous solution.
[H+] = 1 × 10-10 =[OH-] = 1 × 10-4 [OH-] = 1 × 10-4 [H+] = 1 × 10-7 matches Choice, [OH-] = 1 × 10-7 [OH-] = 1 × 10-7 [H+] = 3 × 10-7 matches Choice, [OH-] = 3 × 10-8 [OH-] = 3 × 10-8 [H+] = 5 × 10-2 matches Choice, [OH-] = 2 × 10-13 [OH-] = 2 × 10-13
The H+ ion released by an acid in water is often referred to as a proton because _____
a hydrogen atom without an electron consists of a single proton
In general hydrogen bonds are
about 1/10 as strong as typical covalent bonds
A substance that releases H+ ions in water is called a(n) ________
acid
SO2, NO2, and CO2 all produce _____ solutions in water.
acidic
Something with a pH above 7
basic
Normal seawater is slightly _____ with a pH of around _____.
basic; 8.2
The ability of a covalently bonded atom to attract the shared electrons is called _________
electronegativity
If a chemical reaction is reversible, it occurs in both the forward and reverse directions at once, allowing the system to reach a(n) _______ if the system is closed.
equilibrium
The H+ ions produced by an acid in aqueous solution associate strongly with H2O to form the ______ ion, which has the formula ______.
hydronium; H3O+
A(n) _______ force or attraction is an attraction that occurs between molecules.
intermolecular
Hydrogen bonding is an example of a _____ force
intermolecular
The attraction indicated by the arrow in the illustration is a(n) _____.
intermolecular force
Electronegativity
is a measure of an atom's attraction for an electron in a chemical bond.
If a solute dissolves in water to form a solution that does not conduct an electric current, the solute is a(n) _______.
nonelectrolyte or non-electrolyte
The symbol ⇌ used in an equation indicates that a particular reaction _______.
occurs in both the forward and reverse directions at the same time
BOD is a measure of the amount of dissolved _____ microorganisms use up as they decompose organic wastes found in water.
oxygen
What are the major disadvantages of using Ozone instead of chlorine to disinfect water?
ozone does not provide long-term protection against waterborne viruses because it decomposes quickly and it is more expensive than chlorination
The ______ scale, which usually ranges between 0 and 14, indicates the acidity of a solution.
pH
Water that is safe to drink and to cook with is called _______ water.
potable
An acid releases H+ ions in water. The H+ ion is a hydrogen atom that has lost its electron, and is therefore often referred to as a(n) _______.
proton
Which of the following bodies of water is/are included in the natural water cycle? Select all that apply.
rivers lakes sea ice glaciers
Type the chemical name for NaOH.
sodium hydroxide
An acid that dissociates completely in aqueous solution is called a(n) _____ acid.
strong
A polar covalent bond is created when
two atoms share their bonding electrons unequally.
which is not a consequence of hydrogen bonding between water molecules?
water is colorless and odorless
A _________ base such as ammonia (NH3) only partially dissociates into ions, whereas potassium hydroxide (KOH) is called a __________ base since it completely dissociates.
weak; strong
