B1: Describe how the polarity of the water molecule results in hydrogen bonding.
Hydrogen bonding happens because a part of water molecule is negatively charged while another part is positively charged. The hydrogen part in a water molecule is attracted to the negatively charged part of another water molecule, while the oxygen part of water is attracted to the positively charged part of another water molecule. The positively charged part of a water molecule is located in the hydrogen part, because when hydrogen forms a covalent bond with oxygen, the hydrogen almost becomes a complete positive charge (the electron in the hydrogen atom is strongly pulled to the oxygen; that is why it appears that the hydrogen atom only contains one proton, one neutron, and almost no electron). When hydrogen forms a bond with either oxygen, fluorine, and nitrogen, the corresponding bond is called hydrogen bonding.
B2: Describe the role of the water molecule as a solvent, temperature regulator, and lubricant.
Water is the universal solvent and facilitates chemical reaction both outside of and within living systems.When a salt like sodium chloride (Na+ and Cl-) is put into water, the negative ends of the water molecules are attracted to the sodium ions, and the positive ends of the water molecules are attracted to the chloride ions. This makes both of them separate.
The temperature of liquid water rises and falls slowly, preventing sudden or drastic changes. The many hydrogen bonds that link water molecules cause water to absorb a great deal of heat before it boils.
Water has a high heat of vaporization, keeping the body from warming up. Hydrogen bonds are broken when water is changed to steam; this accounts for the very large amount of heat needed for evaporation. This property also helps moderate the earth’s temperature so that life can continue to exist.
Hydrogen bonding happens because a part of water molecule is negatively charged while another part is positively charged. The hydrogen part in a water molecule is attracted to the negatively charged part of another water molecule, while the oxygen part of water is attracted to the positively charged part of another water molecule. The positively charged part of a water molecule is located in the hydrogen part, because when hydrogen forms a covalent bond with oxygen, the hydrogen almost becomes a complete positive charge (the electron in the hydrogen atom is strongly pulled to the oxygen; that is why it appears that the hydrogen atom only contains one proton, one neutron, and almost no electron). When hydrogen forms a bond with either oxygen, fluorine, and nitrogen, the corresponding bond is called hydrogen bonding.
B2: Describe the role of the water molecule as a solvent, temperature regulator, and lubricant.
Water is the universal solvent and facilitates chemical reaction both outside of and within living systems.When a salt like sodium chloride (Na+ and Cl-) is put into water, the negative ends of the water molecules are attracted to the sodium ions, and the positive ends of the water molecules are attracted to the chloride ions. This makes both of them separate.
The temperature of liquid water rises and falls slowly, preventing sudden or drastic changes. The many hydrogen bonds that link water molecules cause water to absorb a great deal of heat before it boils.
Water has a high heat of vaporization, keeping the body from warming up. Hydrogen bonds are broken when water is changed to steam; this accounts for the very large amount of heat needed for evaporation. This property also helps moderate the earth’s temperature so that life can continue to exist.
B3: Distinguish among acids, bases and buffers.
Acid:
pH level: less than 7
Physical Characteristics: depending on the temperate, acids can be seen in solid, liquid or gaseous form. taste sour.
Strength: depends on concentration of the hydronium ions.
Phenolphthalein: colorless
Chemical Formula: an acid has a chemical formula with H at the beginning of it. For example, HCl (Hydrochloric Acid). There is one exception to his rule, CH3COOH = Acetic Acid (vinegar)
Litmus Test: acids change litmus paper red
Base:
pH level: more than 7
Physical Characteristics: bases feel slippery because of the reaction of the base with the oils of your hand. Frequently solids except ammonia which is a gas. Taste bitter
Strength: depends on concentration of the hydroxide ions
Phenolphthalein: makes it pink
Chemical Formula: A base has a chemical formula with OH at the end of it. For example, NaOH (Sodium Hydroxide).
Litmus Test: Bases change litmus paper blue.
Buffers:
Its pH changes very little when a small or moderate amount of strong acid or base is added to it and thus it is used to prevent changes in the pH of a solution. Buffer solutions are used as a means of keeping pH at a nearly constant value in a wide variety of chemical applications.