Lab Biology

Mrs. Campbell

Fall 2009

Lesson 1 Matter, Energy and Chemical Processes of Life

• Matter – anything that has mass and takes up space.

• Atom – the basic unit of matter.

• Molecule – the smallest particle of a substance that has all the properties of the substance.

• Mass – the amount of material an object has.

Lesson 1 con’t Matter, Energy and Chemical Processes of Life

• Chemistry – the study of matter and how it changes

• Bacteria – the simplest single cells that carry out all basic life activities

• Physical Property – a characteristic of a substance or an object that can be observed without changing the substance into a different substance

Lesson 1 con’t Matter, Energy and Chemical Processes of Life

• Chemical Property – a characteristic that describes how a substance changes into a different substance

• Element – a substance that can not be separated into other substances

• Chemical Reaction – a chemical change in which elements are combined or rearranged.

• Chemical Bond – the force holding atoms together in a compound or molecule.

Lesson 2 Atoms and Molecules

• Element Symbol – the one, two or three letters that represents the name of an element. The first letter is always capitalized. If there is more than one letter, the first is capitalized and the others are lower case.

• Compound – a substance that is formed when atoms of two or more elements join together.

• Atoms are composed of subatomic particles.

• Subatomic Particle – a proton, neutron, electron or other particle smaller than the atom.

Lesson 2 con’t Atoms and Molecules

• The atom consists of a positively charged nucleus surrounded by a negatively charged electron cloud.

• Protons have a positive charge (+) and are found in the nucleus. Neutrons have no charge or are neutral (0) and are found in the nucleus. Electrons have a negative charge (-) and are found in the electron cloud.

Lesson 2 con’t Atoms and Molecules

• Atomic Number – the number of protons in the nucleus of an atom.

• Atomic Mass – the average mass of the atom of an element.

• Isotope – one of a group of atoms of an element with the same number of protons and electrons but a different numbers of neutrons.

• Radioactive – the property of some elements or isotopes to give off energy as they change to another substance over time.

• Radioisotope – a radioactive isotope.

Lesson 3 Chemical Formulas

Chemical Formula – a set of symbols and subscripts that tells the kinds of atoms and how many of each kind are present.

• CH4 is the chemical formula for a molecule of methane. It has 1 atom of carbon and 4 atoms of hydrogen for a total of 5 atoms.

• CO2 is the chemical formula for a molecule of carbon dioxide. It has 1 atom of carbon and 2 atoms of oxygen for a total of 3 atoms.

Lesson 3 con’t Chemical Formulas

More Examples of Chemical Formulas

• If we have 3 water molecules, it would be written as 3H20. We now have 6 atoms of hydrogen and 3 atoms of oxygen.

• If we have 6 sugar molecules it would be written as 6C6H1206. We now have 36 carbon molecules, 72 hydrogen molecules and 36 oxygen molecules.

Lesson 3 con’t Chemical Formulas

• Ion – an atom that has either a positive or a negative charge.

• Examples of Ions = NA+ CL-

• Ionic Compound – two or more ions held together by electrical attraction.

• Examples of Ionic Compounds = NaCl

Lesson 3 con’t Atoms and Molecules

• Radical – a group of two or more atoms that act like one atom.

• Examples of Radicals

SO4 = sulfate

ClO3 = chlorate

NO3 = nitrate

CO3 = carbonate

PO4 = phosphate

Lesson 4Bonding Patterns

• Electrons are the subatomic particles that determine how an atom behaves.

• The farther an electron is from the nucleus, the more energy it has.

• Electrons orbit the nucleus at the speed of light. They orbit in energy levels called electron shells.

• Atoms tend to fill the outermost energy level with electrons.

• Atoms are more stable when its outermost energy level is filled.

Lesson 4 con’tBonding Patterns

• The number of electrons in an atom’s outermost shell determine the atom’s chemical properties.

• A chemical reaction is a chemical change in which the atom’s of elements are combined or rearranged.

• Atoms share, lend, or borrow electrons to fill the outermost shell. When this happens, a chemical bond is formed.

Lesson 4 con’tBonding Patterns

• There are 2 types of chemical bonds.

• Covalent bond – two atoms share one or more pairs of electrons. Atoms held together by covalent bonds form molecules.

• Ionic Bonds – ions are held together by a strong attraction of their opposite charges. A complete transfer of electrons occurs.

Lesson 4 con’tBonding Patterns

• Chemical Reactions – atoms change patterns.

• Reactants – a substance that is altered or changed in a chemical reaction.

• Products – a substance that is formed in a chemical reaction.

2H2 + 02 2 H2O

reactants yields products

Lesson 5Properties of Water

• Polar Molecule – a molecule with an uneven distribution of electrons.

• Hydrogen Bonds – a weak electrical attraction between the slight positive charge on a hydrogen atom and a slight negative charge on another atom.

• Solvent – a substance capable of dissolving one or more other substances.

Lesson 5 con’tProperties of Water

• Hydrophilic – water loving; polar molecules are hydrophilic.

• Hydrophobic – water hating; non-polar molecules are hydrophobic.

• Crystalline – a substance with regularly repeating arrangement of atoms.

Lesson 5 con’tProperties of Water

Examples of Crystalline Structure

Lesson 5 con’t Properties of Water

• Since oxygen has 8 protons, it pulls the electrons more strongly than the 2 hydrogen atoms with only 1 proton each.

• The oxygen end of the water molecule has a slight negative charge.

• The end with the 2 hydrogen atoms has a slight positive charge.

• A molecule in which opposite ends have opposite electrical charges is called a polar molecule.

Lesson 5 con’tProperties of Water

1. Water has a large capacity to hold heat.

2. Water molecules stick together because of hydrogen bonds.

3. Water expands as it freezes.

4. Water is an excellent solvent. Because water is polar, it dissolves ionic substances such as NaCl and polar substances such as sugars.

Lesson 5 con’tProperties of Water

Why is water important to us?

• Organisms are made up of 70% water.

• The cells in your body are 70% to 95% water.

• Water dissolves most biological substances.

Lesson 6Acids, Bases, and pH

• Water can dissociate (break apart) into H+ ions and OH- ions. (OH- = hydroxide ions).

• pH (potential hydrogen) – the concentration of H+ or OH- ions in a solution.

• A solution with more H+ ions than OH- ions is called acidic.

• A solution with more OH- ions than H+ ions is called basic or alkali.

• A solution with equal number of H+ ions and OH- ions is called neutral.

Lesson 6 con’t Acids, Bases, and pH

• Chemical balances and temperature balance in living things are maintained by acid-base reactions.

• The pH scale ranges from 0 to 14. A pH of 7 is considered neutral. A pH below 7 is considered acidic and a pH above 7 is considered basic or alkali.