states of water
the water molecule
Water is simply two atoms of hydrogen and one atom of oxygen bonded together (Figure 1.1). The hydrogen ions are on one side of the oxygen ion, making water a polar molecule. This means that one side, the side with the hydrogen ions, has a slightly positive electrical charge. The other side, the side without the hydrogen ions, has a slightly negative charge. Despite its simplicity, water has remarkable properties. Water expands when it freezes, has high surface tension (because of the polar nature of the molecules, they tend to stick together), and others. Without water, life might not be able to exist on Earth and it certainly would not have the tremendous complexity and diversity that we see.
three states of matter
Water is the only substance on Earth that is present in all three states of matter - as a solid, liquid or gas. (And Earth is the only planet where water is abundantly present in all three states.) Because of the ranges in temperature in specific locations around the planet, all three phases may be present in a single location or in a region. The three phases are solid (ice or snow), liquid (water), and gas (water vapor). See ice, water, and clouds (Figure 1.2). (a) Ice floating in the sea. Can you find all three phases of water in this image? (b) Liquid water. (c) Water vapor is invisible, but clouds that form when water vapor condenses are not. Click image to the left or use the URL below. URL:
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what is a polar molecule?
--> a) a molecule with a slightly imbalanced electrical charge. b) a molecule that is slightly positively charged. c) a molecule that is slightly negatively charged. d) a molecule that is colder than other molecules.
water molecules have this kind of charge.
a) negative b) in between c) positive --> d) no charge
when water freezes, water can do this.
a) changes to the liquid state --> b) expands c) contracts d) evaporates
hydrogen atoms have this kind of charge.
a) negative b) in between --> c) positive d) no charge
why does water have high surface tension?
--> a) the polar molecules stick together, positive side to negative side. b) the water molecule is very tightly bound, hydrogens to oxygen. c) the water droplet sends a glue-like substance to its surface. d) hydrogen and oxygen do cross-bonding, which makes them stick together more.
which of these is a special property of water?
a) water molecules can stick together b) water has a high surface tension c) expands when it freezes --> d) all of the above
all three phases of water can be present in a single location.
--> a) true b) false
earth is not the only planet that has water in all three states and water is the only substance that is found on earth in all three states.
--> a) true b) false
the three states of matter for water are
a) ice, snow and liquid --> b) ice, liquid water and water vapor c) solid, liquid and snow d) snow, solid water and gas
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