Honors Biology- Chemistry Review: Campbell Ch 2-3
1. Complete the following conversions:
5.65 g = 0.00565 kg0.056 m = 56 mm174 mL =0.174L
711 kg = 711,000 g3.79 km = 3790 m0.006 L = 6000 μL
0.074 g = 74 mg745 μm =0.0745 cm127 μL =0.127mL
302°C = 575 K185 K =-88 °C100°C =373 K
2. Express the following measurements in scientific notation:
246.983 = 2.46983 x 10217.2 = 1.72 x 1010.00053 = 5.3 x 10-4
0.06713 =6.713 x 10-2150 = 1.5 x 102100,005 = 1.00005 x 105
132,987,000 = 1.32987 x1080.3 = 3 x 10-1
3. Round each of these measurements to three significant figures:
24.590 = 24.6 24.353 = 24.43.002 =3.00956.789 = 957
67.963 = 68.0 102.06 =102102.6 =10399.88 =99.9
4. A block of rock salt has a mass of 10.7 g. Each edge of the block has a length of 5.00 cm. What is the density of the rock salt?
m= 10.7g
v= 125cm3D= m/v
D= 0.0856g/cm3
5. Indicate whether the substances below are compounds or elements:
SO2:CS8:EC60:ECH4:C
He:EN2:ENaCl:CH2O:C
6. What is an isotope? Same element but different number of neutrons (results in a different mass number)
7. What is the octet rule? Explain its relationship to chemical bond formation.
Atoms will share, gain, or lose electrons in order to be stable (have a complete valence); this process involves either covalent or ionic bonds.
8. Complete the table below:
Isotope / Symbol / # of protons / # of electrons / # of neutrons / Atomic # / Mass #Carbon-12 / 6 / 6 / 6 / 6 / 12
Carbon-14 / 6 / 6 / 8 / 6 / 14
Tin-119 / 50 / 50 / 69 / 50 / 119
Tin-120 / 50 / 50 / 70 / 50 / 120
Iron-56 / 26 / 26 / 30 / 26 / 56
Lithium-7 / 3 / 3 / 4 / 3 / 7
Sodium-23 / 11 / 11 / 12 / 11 / 23
9. Explain why atoms of the noble gases do not easily form bonds, unlike most other atoms.
They have a full valence already and are stable.
10. Ca+2O-2I-1
Xe Rb+1N-3
11. Write the chemical formulas for the ionic compounds formed from the following:
A) magnesium and iodine: MgI2C) sodium and sulfur Na2S
B) Fe3+ and oxygen: Fe2O3D) Pb2+ and nitrogen: Pb3N2
12. What is the difference between a nonpolar covalent bond and a polar covalent bond?
In a nonpolar covalent bond, atoms are approximately equal in electronegativity & neither atom pulls the electrons more towards them; in a polar covalent bond, one of the atoms pulls the shared electrons towards them more.
13. What is a hydrogen bond? A weak bond between a slightly negative atom & a slightly positive atom of different molecules.
14. Depict the hydrogen bond formed between:
A) two water molecules
B) a water molecule & an ammonia (NH3) molecule
15. Balance the following equations:
A) CH4+2 O2CO2 + 2 H2O
B) 2 Sb+3 I22 SbI3
C)3 H2+N22 NH3
D)6 CO2+6 H2OC6H12O6+6 O2
16. Determine the molar mass (g/mol) of the following compounds:
A) CO2 44g/molC) C6H12O6180g/mol
B) NaCl 58.5g/molD) H2CO3 62g/mol
17. How many grams of lactic acid (C3H6O3) are in 1 L of a 0.5 M solution of lactic acid?
(1L) (.5mol/L) (90g/mol) = 45g (units cancel)
18. How many grams of salt (NaCl) must be dissolved in water to make 2 liters of a 2.0 M salt solution? (2L) (2mol/L) (58.5g/mol) = 234g
19.What causes a solution to become acidic? Increase in hydrogen ion concentration of a solution
Basic? Reduction of hydrogen ion concentration of a solution
Neutral? Equal #’s of H+ and OH- ions
20. What does the pH scale measure?Concentration of H+ and OH- in a solution.
21. Describe how buffers help to maintain the pH of solutions and why this would be important in living organisms.
Buffers help to maintain the pH of solutions by accepting or donating hydrogen ions from the solution when they are in excess or have been depleted.
22. Define the following terms which apply to solutions:
A) solute: dissolved by solvent
B) solvent: dissolving agent of a solution
C) aqueous solution: solution where water is the solvent
D) hydrophilic: water loving
E) hydrophobic: water “fearing” (won’t dissolve in water or other polar solvents)
23. Indicate whether the following compounds are hydrophilic or hydrophobic. Do these substances contain ionic, polar, or nonpolar bonds?
A) olive oil: hydrophobic; nonpolar
B) sugar: hydrophilic; polar
C) salt: hydrophilic; ionic
D) candle wax: hydrophobic; nonpolar
24. Complete the following concept map illustrating how hydrogen bonding in water contributes to temperature regulation.
a) water molecule
b) absorbed
c) released
d) specific heat
e) heat of vaporization
f) evaporative cooling
g) solar energy/ heat
h) rain clouds
i) ice
25. List the 4 major classes of macromolecules.
Lipid, Protein, Carbohydrate, Nucleic Acid
26. What is a monomer? Small molecule that serves as a building block for
a polymer
What is a polymer? Large molecule consisting of many similar identical
building blocks linked by covalent bonds
27. Describe how a number of individual cars linked together forming a train is an appropriate analogy for the formation of a macromolecule.
Individual cars represent the monomers which are linked (or bonded) together to form a long molecule (train or polymer)