hw #8

____ % of all the water on Earth is salt water. Fresh water takes up only ___%. Out of this fresh water the readily available fresh water for humans, such as waters from lakes, rivers and streams, accounts less than ____ %. Which option correctly lists the numbers in the order of the blanks above? 97, 3, 30 97, 1, 3 97, 3, 1 97, 3, 3

97, 3, 1

Which statement is false? The boiling point of water is lower at high altitude that at low altitude.NO When we boil water at higher alitude, we are to observe that more bubbles tend to persist than would do at lower alitude. NO Some water molecules that are not on the surface even become water vapor (i.e., gas molecules in tiny bubbles) for an instant as the water heats up. The earlier the pressure of the water vapor becomes the same as the atmospheric pressure, the later the boiling point of water occurs. No answer (i.e., all options above are true.)

??

What is a hydrogen bond? A hydrogen bond is the intermolecular attractive force between polar molecules that have a hydrogen atom bonded to either a nitrogen, oxygen, or fluorine atom. A hydrogen bond is the covalent bond between a hydrogen atom and a carbon atom. A hydrogen bond is the intermolecular attractive force between diatomic hydrogen molecules. A hydrogen bond is the covalent bond in polar molecules that have a hydrogen atom.

A hydrogen bond is the intermolecular attractive force between polar molecules that have a hydrogen atom bonded to either a nitrogen, oxygen, or fluorine atom.

Why desalination has not contributed significantly to the global demand for fresh water? Because the life span of desalination plants is very short as they generate huge amounts of salt sludges. Because it is expensive to build desalination plants and they use great amounts of energy. Because technological difficulties in maintaining desalination plants are yet to be overcome. Because desalinated water does not taste as good as natural fresh water.

Because it is expensive to build desalination plants and they use great amounts of energy.

Which statement is false? Water has a high specific heat. If the same amount of heat is added to the same amount of water and soil, the temperature of water rises by a smaller value than the temperature of soil does. This is because water has a high specific heat. If the same amount of heat is added to the same amount of water and soil, the temperature of water rises by a larger value than the temperature of soil does. This is because water has a high specific heat. The degree of the temperature increase of water in response to the amount of heat being added is not so steep as in the case of most other substances. This is because water has a high specific heat.

If the same amount of heat is added to the same amount of water and soil, the temperature of water rises by a larger value than the temperature of soil does. This is because water has a high specific heat.

Read Green Beat at the end of Chapter 8 and select the statement which does NOT correctly convey its content. The counties with the highest level of lithium in the water showed significantly reduced crime rates. Lithium is the most commonly prescribed drug for some serious psychiatric disorders. The idea of adding small amount of lithium to drinking water was not well-accepted by the public. Lithium like fluoride has been proved to be very effective in preventing cavities.

Lithium like fluoride has been proved to be very effective in preventing cavities.

What type of process occurs when an ice cube turns into liquid water? The ice is condensing, and it is an endothermic process. The ice is condensing, and it is an exothermic process. The ice is melting, and it is an exothermic process. The ice is melting, and it is an endothermic process.

The ice is melting, and it is an endothermic process.

What happens when water evaporates? The water molecules have absorbed enough energy to overcome the hydrogen bonding intermolecular attractive forces and the water goes through a phase change. The water molecules have enough energy to break the covalent bonds and a chemical reaction occurs. The polarity of the water molecule keeps the water molecules closely packed together. The net dipole of the water molecules allows the water molecules to easily overcome the ionic bonding forces of attraction.

The water molecules have absorbed enough energy to overcome the hydrogen bonding intermolecular attractive forces and the water goes through a phase change.

Which statement is false? In a water molecule, electron density is pulled toward the oxygen atom. Hydrogen bonds are the strongest type of intermolecular force. The structure of ice contains a lot more empty space than that of liquid water, causing the density of ice to be lighter than that of liquid water. There are covalent bonds among water molecules. No answer (i.e. all options above are true.) NO

There are covalent bonds among water molecules.

Which statement is describing intermolecular forces? Methane can react with oxygen to form carbon dioxide and water. Water molecules are formed from the covalent bonding between an oxygen atom and two hydrogen atoms. Water is cooled and the ice forms a hexagonal shape. Methane molecules have a tetrahedron shape.

Water is cooled and the ice forms a hexagonal shape.

on a heating curve, what happens when a liquid starts to turn into a gas? When the liquid reaches its boiling point temperature, the temperature increases steadily until all of the molecules turn into a gas. NO When the liquid reaches its boiling point temperature, the temperature stays constant until some of the molecules turn into a gas. When the liquid reaches its melting point temperature, the temperature increases steadily until some of the molecules turn into a gas. When the liquid reaches its melting point temperature, the temperature stays constant until all of the molecules turn into a gas.

When the liquid reaches its boiling point temperature, the temperature stays constant until some of the molecules turn into a gas.

Which country is NOT among the top three users of desalination plants? USA Australia Saudi Arabia United Arab Emirates

aussie

Which city shows the greatest fluctuation of the average temperature in June? Denver, CO Chicago, IL Miami, FL San Francisco, CA

denver

According to Green Beat at the end of Chapter 8, fluoride is the substance recently proposed by a dentist to be added to the water supplies in the US. True False

false

The specific of a substance is the amount of heat energy required to raise the temperature of gram of a substance by degree

heat, 1, 1, celsius

Which statement is true? Formation of ice crystals escalate the hurricane's intensity. But this process can't occur during the formation. Formation of ice crystals reduce the hurricane's intensity. This is because heat is released during the ice formation. Formation of ice crystals escalate the hurricane's intensity. And this formation occurs at the bottom of the storm where the air mass is cold. Formation of ice crystals escalate the hurricane's intensity. Because heat is absorbed during the formation. No answer (i.e., all options above are false.)

none

What is the correct order of the treatment steps that occur in a typical water treatment plant? settling, disinfection, flocculation, disinfection/fluoride, filtration, screen screen, flocculation, settling, disinfection, filtration, disinfection/fluoride disinfection/fluoride, settling, screen, flocculation, filtration, disinfection flocculation, screen, disinfection, filtration, disinfection/fluoride, settling

screen, flocculation, settling, disinfection, filtration, disinfection/fluoride

Based on the following information, which substance has the highest melting point temperature?Table salt is a solid at room temperature.Mercury is a liquid at room temperature.Water is a liquid at room temperature.Methane is a gas at room temperature. methane table salt mercury water

table salt

Which country has the greatest water footprint per person per year? USA United Kingdom China Republic of Congo

usa