Study Guide: chemical bonds, acids, bases, water, chemical reaction, common assessment
Complete the following
Characteristic
pH
Acid
0-6
Base
8-14
Ion formed when mixed
with water
Donates or accepts H+
atoms
Taste
H3 O+
OH-
Donates
Accepts
Sour
Bitter
Examples
Citrus, soft drinks,
stomach acid, lemon juice
Cleaning products, alka
seltzer, see book for more
1. What molecule is formed when an acid and base are mixed together? What is the name of this reaction?
Water, neutralization reaction
2. Label the following substances as strongly acidic, mildly acidic, strongly basic, mildly basic, or neutral?
a. Acetic acid pH = 5.8 mildly acidic
b. Water pH = 7 neutral
c. Sulfuric Acid (H2SO4) pH = 2
strongly acidic
d. Oven cleaner pH = 13 strongly basic
3. What does the pH of a substance measure to determine whether a substance is an acid or a base?
Hydrogen (H+) ions
4. Explain the following characteristics of water and give an example from the water lab where the
characteristic was observed.
a. Surface tension
measure of how difficult it is to break the surface of a liquid,
examples: bubble forming on top of cup of water, paper clip floating on water
b. Cohesion the attraction of water to itself (causes surface tension of water), possible
because of hydrogen bonds, Examples: bubble forming on top of cup of water, bead
forming on wax paper
c. Adhesion ability of water to stick to other surfaces, microscope slides sticking together
5. What property of water gives it the following characteristics listed above? Hydrogen bonding ( oxygen
of one water molecule is attracted to the hydrogen of another water molecule)
6. Why is solid ice able to float on top of liquid water? Solid ice is less dense than liquid water
7. Explain the difference between hydrophobic and hydrophilic substances. Include in your explanation
what makes a substance hydrophilic or hydrophobic and which category polar and nonpolar substances
fall into. Also, include some examples of hydrophilic and hydrophobic substances.
Hydrophobic: fear water, molecule does not have positively and negatively charged ends (shares
electrons equally), nonpolar substances, examples: oil, butter, fats
Hydrophillic: mix with water (water loving), molecule has positively and negatively charged ends,
polar, examples: food-coloring, water, salt
8. What makes a molecule polar or nonpolar? Polar molecules have positively charged and negatively
charged atoms and nonpolar molecules do not have any charges on the atoms
9. For the following picture, identify the type of bond the arrow is pointing to.
covalent
hydrogen
10. How many electrons are shared between two atoms in a single covalent bond? Double bond?
Two electrons are shared in a single bond and 4 electrons are shared in a double bond
11. What is the purpose for atoms bonding together? So atoms can have a filled valence shell (eight or
two electrons) and become more stable like a noble gas
12. Explain the differences between ionic and covalent bonds.
 Ionic: electrons are not shared equally, some atom(s) gain electrons while other
atom(s) lose electrons, forms between a metal and a nonmetal
 Covalent: electrons are shared equally between atoms, forms between nonmetal
atoms
13. What is the name of a substance that conducts electricity? electrolyte
14. Explain the transfer of energy between a substance and its surroundings in an endothermic reaction and
an exothermic reaction.
 Endothermic: energy is transferred from the surroundings to the substance
 Exothermic: energy is transferred from the substance to the surroundings
15. What happens during a chemical reaction? Atoms are rearranged to form new molecules
16. What part of a chemical equation must be changed to balance the chemical equation?
(number placed in front of the molecule)
Coefficient
17. On what side of a chemical equation are the products on? The reactants? Products are on the righthand side and reactants are on the left-hand side (like reading a book, start on the left and move
to the right)
For each molecule, draw the lewis structure of the individual atoms, the complete molecule, and
determine whether it contains an ionic or covalent bond. See bonding packet for answers
on how to draw the molecules.
18. LiF
Ionic
19. BaBr2 Ionic
20. F2
covalent
21. RbCl Ionic
22. NH3
Covalent
Common Assessment
1. For the following chemical reaction, predict what the product will be.
CH4 + 2O2  CO2 + 2 _H2O____
2. How many total atoms of carbon (C) are represented by the following chemical formula,
2C6H12O6 ? 12
3. What is the octet rule?
States that atoms want to gain or lose electrons so that they
have a filled valence shell like the nearest noble gas
4. Balance the following chemical reactions:
____ Fe3O4 +
2
K +
_4_ H2 
Br2  2
__3__
Fe +
4_ H2O
KBr
5. Explain the law of conservation of mass. Mass is never created nor destroyed (it only
changes forms)
6. An experiment was performed in the SI lab. The mass of the experiment was recorded before
and after the reaction. The products of the chemical reaction contained less mass than the
reactants. Give a possible explanation for this observation. (Hint: the law of conservation of
mass is never violated). How could you change the experiment, so that the total mass of the
reactants equals the total mass of the products.
If it was an open system, some of the mass could have been transferred into the
surroundings. Some of the mass could have also been transferred into heat. The
experiment could be changed by performing it in a closed system, so that less of the mass
is transferred to the surroundings.