1. Chapter 2 Chemistry of Life

2. I. Composition of Matter
Matter is anything that has mass and takes up space
Mass is the quantity of matter an object has
Weight is a force produced by gravity acting on mass

3. Elements
Substances that cannot be broken down chemically into simpler kinds of matter
Found on the periodic table
Oxygen, carbon, hydrogen and nitrogen are the four elements that make up most living things (in different combinations of course)

4. Atom
Simplest particle of an element that retains all the properties of that element
Contains
Protons
Neutrons
Electrons

5. Where to find information on the periodic table
Atomic number = number of protons
Mass number= number of protons plus neutrons

6. II. Energy The ability to do work
Energy can only be transferred from one form to another

7. States of Matter States of matter only change if energy is added or lost
Solid
Particles close together
Particles move slow
Fixed volume
Fixed Shape
Liquid
Particles spaced further apart
Particles move faster
Shape of container
Gas
Particles even further
Particles move most rapidly
Fill volume of container

8. Chemical Reaction
One or more substances change in order to produce one or more substances (basically substances change into other substances)
Chemical bonds are either broken (energy is released) or formed (energy is absorbed)

9. Example of chemical reaction
Reactants  Products
CO2 + H2O  H2CO3
Metabolism is the sum of all the chemical
reactions in your body

10. Activation Energy
The amount of energy needed to start a chemical reaction (normally very high)
Catalysts help reduce the amount of activation energy needed to start a reaction
Enzymes are proteins that help speed up chemical reactions in living things without being destroyed in the reaction

13. III. Water and Solutions
Water is very important
It is formed by covalent bonds between two hydrogen and one oxygen
Because there is an unequal sharing of electrons (oxygen is a hog) the molecule is polar
A polar molecule is one with a charge
Negative in one region (near oxygen)
Positive in another region (hydrogen)

15. Solubility of Water
The polarity of water allows it to dissolve other polar substances
such as sugars and salts, ionic compounds and some proteins

16. Hydrogen Bonds
Force of attraction between a hydrogen molecule with a partial positive charge and another atom or molecule with a partial or full negative charge
Enable water to have adhesive and cohesive properties

17. Forces
Cohesion- attractive force that holds molecules of a single substance together (ex. water and water)
Contributes to the upward motion of water from roots to leaves of a plant
Adhesion- attractive force between two particles of different substances (ex water and glass)
Two wet microscope slides together

18. Water is so AMAZING!
Can absorb or release large amounts of energy in the form of heat with only a slight temperature change (hydrogen bonds)
The shape of the water molecule makes its solid form (ice) less dense than water, therefore lakes and ponds freeze from the top down, allowing aquatic life to survive under the icy surface

19. Water is the universal solvent!!
Solution
Solute  substance dissolved
Solvent substance doing the dissolving
Aqueous solution  one with water as the solvent
Saturated solution contains the maximum amount of solute
Concentration- amount of solute dissolved in a fixed amount of solution

20. Acids and Bases
Hydroxide ion is OH- and is in greater concentration in bases (alkaline)
pH (7.1-14)
Hydronium ion is H3O+ and is in greater concentration in acids
pH (0-6.9)

22. Multiple Choice
1. The way in which elements bond to form compounds depends on which of the following?
A. the model of the atom
B. the structural formula of the compound
C. the dissociation of the ions in the compound
D. the number and arrangement of electrons in the atoms of the elements

23. Multiple Choice, continued
Chapter 2
Standardized Test Prep
Multiple Choice, continued
1. The way in which elements bond to form compounds depends on which of the following?
A. the model of the atom
B. the structural formula of the compound
C. the dissociation of the ions in the compound
D. the number and arrangement of electrons in the atoms of the elements

24. Multiple Choice, continued
Chapter 2
Standardized Test Prep
Multiple Choice, continued
2. If an atom is made up of 6 protons, 7 neutrons, and 6 electrons, what is its atomic number?
F. 6
G. 7
H. 13
J. 19

25. Multiple Choice, continued
Chapter 2
Standardized Test Prep
Multiple Choice, continued
2. If an atom is made up of 6 protons, 7 neutrons, and 6 electrons, what is its atomic number?
F. 6
G. 7
H. 13
J. 19

26. 3. The amount of energy needed for this chemical reaction to begin is shown by the line rising from the reactants. What is this energy called?
A. chemical energy
B. electrical energy
C. activation energy
D. mechanical energy

27. 3. The amount of energy needed for this chemical reaction to begin is shown by the line rising from the reactants. What is this energy called?
A. chemical energy
B. electrical energy
C. activation energy
D. mechanical energy

28. 4. Suppose that this reaction needs a catalyst to proceed
4. Suppose that this reaction needs a catalyst to proceed. In the absence of a catalyst, the activation energy would be which of the following?
F. larger than what is shown
G. the same as what is shown
H. smaller than what is shown
J. not much different from what is shown

29. 4. Suppose that this reaction needs a catalyst to proceed
4. Suppose that this reaction needs a catalyst to proceed. In the absence of a catalyst, the activation energy would be which of the following?
F. larger than what is shown
G. the same as what is shown
H. smaller than what is shown
J. not much different from what is shown

30. 5. What is an aqueous solution that contains more hydroxide ions than hydronium ions called?
A. a gas
B. a base
C. a solid
D. an acid

31. 5. What is an aqueous solution that contains more hydroxide ions than hydronium ions called?
A. a gas
B. a base
C. a solid
D. an acid

32. B. Water is a polar molecule.
7. The covalent bonds on the water molecule depicted in the picture above has partial positive charges on the hydrogen atom and a partial negative charge on the oxygen atom. What do the partial positive and partial negative charges on this water molecule mean?
A. Water is an ion.
B. Water is a polar molecule.
C. Water needs a proton and two electrons to be stable.
D. Oxygen atoms and hydrogen atoms have opposite charges. [

33. 7. The covalent bonds on the water molecule depicted in the picture above has partial positive charges on the hydrogen atom and a partial negative charge on the oxygen atom. What do the partial positive and partial negative charges on this water molecule mean?
A. Water is an ion.
B. Water is a polar molecule.
C. Water needs a proton and two electrons to be stable.
D. Oxygen atoms and hydrogen atoms have opposite charges.

34. Short Response
Covalent bonding is a sharing of electrons between atoms. Why do some atoms share electrons?

35. Covalent bonding is a sharing of electrons between atoms
Covalent bonding is a sharing of electrons between atoms. Why do some atoms share electrons?
Answer:
Sharing electrons achieves a stable number of electrons in the orbitals that correspond to the highest energy level for each atom.