chemistry

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

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

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

Al2(SO4)3 and Ca(OH)2 Flocculating agents Cl2, NaClO, or Ca(ClO)2 Antibacterial agents F- Prevents tooth decay

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.

Nitrate ions Organic compounds

A low BOD is an indication of _____ quality water.

good

Ocean acidification is correctly described as _____.

the lowering of ocean pH due to increased atmospheric CO2

What is potable water?

Water that is safe to drink and cook with.

Which of the following options correctly describe the processes that contribute to ocean acidification? (Select all that apply.)

1. Dissolved CO2 reacts with H2O to form H2CO3 2. Increased atmospheric CO2 leads to more CO2 dissolved in the ocean

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

2,100,000,000

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

97% of Earth's water , Oceans 3% of Earth's water , Fresh water 68% of fresh water , Glaciers, ice caps and snowfields 30% of fresh water , Aquifers 1% of fresh water , Atmosphere 0.3% of fresh water Lakes, swamps, rivers

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?

>390L

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

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

Correctly order the steps showing the effect of decreased ocean pH on marine organisms such as coral. Start with the first step at the top of the list.

CO2+H2.... H2CO3+H+ H+(aq)+CO3 CaCO

Which of the following species play a role in maintaining the normal pH of seawater? (Select all that apply.)

CO32- HCO3- H2CO3

Marine organisms such as mollusks, sea urchins, and coral have shells composed of _____ and these species are affected by the levels of _____ ion in seawater.

CaCO3 CO3 2-

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

Which of the following statements describe the drawbacks of using chlorine-containing chemicals in the water treatment process?

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

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 are responsible for protecting coastlines from ocean waves while providing a habitat for a diverse range of aquatic life?

Coral reefs

What are methods used to remove ions from salt water?

Desalination Reverse osmosis Distillation

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

Distillation Reverse osmosis

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: 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 Reason: This is still considered a tragedy of the commons since others are impacted by this action - either deliberate or accidental.

Which of the following options correctly describe the effect of pH on life in a lake or stream?

Fish begin to be affected when the pH of a lake or stream drops below 6.0. If the pH drops to 4.0, a lake is essentially a dead ecosystem. Some hardy aquatic species can survive at a pH of below 5.0.

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

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

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

Click and drag on elements in order Rank the following bonds from the most to the least polar, starting with the most polar bond at the top of list. Instructions

H-F P-O C-O C-H

The levels of which of the following species will have an impact on the formation of the CaCO3 shells of marine organisms such as coral? (Select all that apply.)

HCO3- CO2 CO32-

In what way does increasing ocean acidity affect coral reefs?

Increasing acidity leads to a decrease in the amount of CO32- ion available to build coral reefs.

Which of the following options correctly compare the effect of acid precipitation on lakes in different geological surroundings? Select all that apply.

Lakes in granite areas tend to have lower pH values than lakes in limestone regions. Lakes in limestone regions have a higher acid-neutralizing capacity.

Match each type of lake with the effect acidic precipitation will have on its pH.

Lakes in limestone regions resist a decrease in pH when subjected to acidic precipitation. Lakes in granite regions show a decrease in pH due to acidic precipitation. Excess acid is neutralized by limestone. Excess acid does not react with granite.

Which of the following are possible negative consequences of ocean acidification? Select all that apply.

Loss of a variety of marine species Damage to coastlines Damage to coral reefs from storms

Which of the following molecules is polar?

NH3

The release of _______ gas causes acid rain through formation of nitric acid, HNO3.

NO2

Match each bond with the appropriate difference in electronegativity. Instructions

O-H 1.4 F-H 1.9 S-Cl 0.5 Si-F 2.2

Which of the following would represent an example of a tragedy of the commons? (Select all that apply.)

Overfishing a lake Dumping waste into a public lake

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

Oxygen

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

Oxygen depletion Dead fish Algal blooms

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

Ozone UV radiation

Water that is safe to drink and to cook with is called __________ water.

Potable

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 electronegativity and its trends? Select all that apply.

The element with the highest electronegativity is fluorine. 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.

δ-O <--- H δ+ 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 the O, giving it a partial negative charge

Why are some lakes able to resist a decrease in pH when exposed to acidic precipitation and/or runoff?

The soils or rocks surrounding the lake may contain bases, which neutralize the acid.

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.

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

Water Footprint

The capacity of a lake or other body of water to resist a decrease in pH when exposed to acidic precipitation or runoff is called its _____ capacity.

acid-neutralizing

An _____ is a source of freshwater located underground.

aquifer

Naturally occurring underground reservoirs containing fresh water are called _____.

aquifers

Normal seawater is slightly _____ with a pH of around _____.

basic; 8.2

Fresh water found in an aquifer is located:

below ground (groundwater)

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

electronegativity

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

lakes sea ice rivers glaciers

δ-

marks the atom with the higher electronegativity

δ+

marks the atom with the lower electronegativity

Match each pH range to the effect it has on organisms found in a lake.

pH = 6.5 or slightly higher normal, healthy lake pH below 6.0 many fish disappear pH below 5.0 most aquatic life disappears pH of 4.0 or lower the lake is essentially dead

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

polar covalent

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

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