Chapter 2 - Chemistry of Life
Section 1 – Composition of Matter
Section 2 – Energy
Section 3 – Water and Solutions
Objectives
Define the term matter
Explain the relationship between elements and atoms.
Explain the relationship between enzymes and activation energy.
Describe the structure of a water molecule.
Explain how water’s polar nature affects its ability to dissolve substances.
Differentiate between acids and bases.
Section 1 – Composition of Matter
Composition of Matter
______is anything that takes up space and has mass.
______is the measure of the amount of matter that an object contains.
______is the basic building block of matter
◦Composed of electrons, protons, and neutrons.
______are found in the nucleus
______move about the nucleus in orbitals or electron clouds.
Atom (Draw an atom)
Elements
______are substances that cannot be broken down chemically into simpler kinds of matter.
◦______arranged on the periodic table
______are atoms of the same element that differ in their number of neutrons.
Compounds
______are a chemical combination of two or more elements.
◦Held together by bonds
______result from electron transfer
______result from electron sharing
8 is a magic number (2 in the case of small elements)
Two type of compounds
Ionic compounds
Covalent compounds
Section 2 - Energy
Energy
______is the capacity to do work
States of Matter
Three common states of matter:
◦______
◦______
◦______
Fourth type:
◦______: an ionized gas
Solid
______- a substance in which the particles occupy fixed positions in a well-defined, three-dimensional arrangement.
◦Definite shape and volume.
◦Examples:
Iron
Ice
Liquid
______- a flowing substance with a definite volume but an indefinite shape.
◦Definite volume and takes shape of container
◦Examples:
Water
Mercury
Bromine
Gas
______– a flowing, compressible substance with no definite shape or volume.
◦Takes shape and volume of container
◦Examples
Oxygen
Hydrogen
Helium
Chemical Reactions
______occurs when one or more substances change into new substances
◦______– starting substances in a chemical reaction.
◦______– the ending substances in a chemical reaction.
Activation Energy
______is the amount energy required in order for a reaction to take place.
______speed of chemical reactions by lowering the activation energy.
______are biological catalysts
◦Without them the chemical reactions in the body would occur so slowly we would not survive.
Oxidation-Reduction Reactions
______(Oxidation-Reduction Reaction) –electrons transfer from one atom to another.
______– a reactant loses one or more electrons = positive ion
______– a reactant gains one or more electrons = negative ions
Section 3 – Water and Solutions
Molecular Shape and Properties
A water molecule is composed of two hydrogen atoms and one oxygen atom (H2O).
The oxygen end of the molecule carries a negative charge and the hydrogen end of the molecule carries a positive charge.
Shape of water
The ______of the water molecule gives a partial negative charge around the oxygen area, and a partial positive charge around the hydrogen atoms. With both partial positive and negative charges being present on the molecule, both positive and negative charges are attracted to it.
Polarity
The polar nature of water allows it to dissolve many different substances.
Polarity due to an unevenly distributed charge on the molecule.
Due to its molecular structure, water is a ______. Therefore, it can dissolve many ionic substances, such as salt, and polar substances, such as sugar. As a result of the solvent properties of water, the liquid always contains dissolved materials, particularly ionic substances.
Water is known as the ______because it dissolves such a large number of substances. More substances are soluble in water than in any other liquid. Water's ability to dissolve so many substances is due to its polar nature.
Polarity of Water
Hydrogen Bonding
______is the force of attraction between a hydrogen molecule with a partial positive charge and between another atom or molecule with a partial or full negative charge.
Hydrogen bonds in water exert an attractive force strong enough so that water “clings” to itself and some other substances.
◦Hydrogen bonds form, break, and reform with great frequency.
Cohesion and Adhesion
______attractive force that holds molecules of a single substance together.
◦Water molecules move upward through the roots of plants.
______– attractive force between two particles of different substances, such as water molecules and glass molecules.
◦______– attraction between molecules that results in the rise of the surface of a liquid when in contact with a solid.
Cohesion and Adhesion
Temperature Moderation
Water has a high heat capacity, which means that water can absorb or release large amounts of energy.
Keeps it cool during the day be absorbing heat and warm at night by radiating it off at night.
Solutions
______ – the dissolving agent
______ – the thing begin dissolved
______– solutions in which the solvent is water
Acids and Bases
Hydronium ions are greater than the number of hydroxide ions – Acid
Hydroxide ions are greater than the number of hydronium ions - Base
pH Scale
Buffers
______are chemical substances that neutralize small amounts of either an acid or a base.
Buffers help us to maintain the pH values in a normal healthy body