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7 Cards in this Set
- Front
- Back
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What is the structure of the water molecule?
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The water molecule is made up of two atoms of hydrogen and one atom of oxygen. The two hydrogen atoms are closer together than the hydrogen and oxygen atom.
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In terms of charges describe the structure of the water molecule.
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The distribution of the charges on a water molecule is unequal. The oxygen atom pulls the bonding electrons towards it, which makes the oxygen slightly negatively charged. The hydrogen atoms have small positive charges. This unequal distribution of charge is called a dipole.
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In terms of bonds, describe the structure of the water molecules.
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The slightly negative oxygen atoms attract the slightly positive hydrogen atoms of other water molecules and the weak electrostatic attraction between them is called a hydrogen bond.
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Draw a simple structure showing two polar water molecules
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Why is water a good solvent?
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Water is polar, which means that the charges are unevenly distributed. The tiny charges water molecules attract other molecules or ions that have charges on them. The hydrogen bonds are covalent so they are weak and easily broken to react with other ions
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Using sodium chloride as an example, explain how water is advantageous as a solvent for it.
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Sodium chloride is an ionic compound, so when it is dissolved in water the ions move around freely (Na +, Cl -). These ions are attracted to the dipoles of the water molecule. The solution becomes more chemically reactive as it is in the liquid state and the bonds are not as strong as those in a solid.
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What is the role of water as a solvent in living organisms both systematic and cellular?
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Many reactions including most metabolic reactions will only take place in a solution because this makes it possible for ions or molecules to come in contact with each other.
Cytoplasm contains many different substances dissolved in water. Water can flow so it can carry dissolved substance from one place to another. This happens in the blood and in the xylem vessels and phloem sieve tubes of a plant. Urea is removed from the body by being dissolved in water. |
