chem106 unit 1
What percentage of public water supplies in the United States do NOT meet one or more of the EPA water standards?
10%
What percentage of water on the earth is fresh water?
2%
Contaminated water supplies and lack of adequate sanitation kill approximately ________ people worldwide each year.
3,600,000
How much heat, in calories, does it take to warm 935 g of iron from 12.0 ∘C to 45.0 ∘C?
3300 calories
How much water does the average American use in one day?
400 L
About ________ of the world's fresh water supply is used in agriculture.
70%
Which federal agency regulates drinking water standards from municipal water supplies?
EPA
_______ ___________ is a measure of the heat required to raise the temperature of 1 gram of a substance by 1C
Heat capacity
One of the advantages of treating sewage effluent with ozone as opposed to chlorine is
O3 is more effective in killing viruses
the use of plants to remove metals or other contaminants
Phytoremediation
How is charge distributed in a molecule of water?
There is a positive partial charge on the H atoms and a negative partial charge on the O atom.
How much water does a person need per day for drinking?
about 2 L
If the BOD is high enough, other organisms ______survive, leading to a dead zone.
cannot
Which treatment method is best at removing trihalomethanes such as chloroform?
charcoal filtration
The process by which a gas is converted to a liquid is called
condensation
Which of the following processes involves the removal of energy (heat)?
condensation
What uses the greatest amount of water in the United States?
cooling for electric power plants
Which of the following uses the greatest amount of water in the United States?
cooling for electric power plants
What is the predominant intermolecular force between ClF molecules?
dipole forces
bottled mineral water often contains more _______ ______ than tap water
dissolved ions
What common human activities contribute to BOD?
dumping detergents in a lake or pond
Heat of vaporization is the ______ required to ________ a substance.
energy vaporize
Water ______ when it freezes, which lowers the density of ice with respect to liquid water.
expands
true or false? A covalent bond is weaker than a hydrogen bond.
false
true or false? The Clean Water Act has had no impact on water quality over the past two decades.
false
true or false? The major use of water in the United States is for public water supplies.
false
Secondary treatment of sewage involves _______ and ________
filtering and aeration
The lower density of ice allows it to _____, making life possible in the liquid water ____ the ice layer.
float below
The dramatic temperature changes on the moon between day and night are not seen on the earth because of what property of water?
high heat capacity
The heat of vaporization of water is high, as compared to other substances, due to ________ ______
hydrogen bonding.
Consumption of water with high levels of nitrate is particularly hazardous to
infants
Which of the following is NOT a property of water?
it has a lower density than most liquids do
Which substance is likely to be produced when the dissolved oxygen in a lake is depleted?
methane
Charcoal filtration of wastewater is an excellent method for the removal of
organic molecules
What substances remain in wastewater after effective secondary treatment?
organic molecules phosphates nitrates
Which of the following processes is not used in a conventional method of water treatment?
percolation
How much heat, in calories, does it take to warm 960 g of water from 12.0 ∘C to 45.0 ∘C?
q= 3.17 x 10^4 calories
Thermal pollution is harmful to aquatic environments because it _______ the amount of _______ ________
reduces dissolved oxygen
Advanced treatment of wastewater can include any of the following EXCEPT --charcoal filtration. --reverse osmosis. --sand and gravel filtration. --phytoremediation.
sand and gravel filtration
Fertilizers ______ the growth of microorganisms, which _______ the biological demand for oxygen (BOD) in the water.
stimulate increases
