General Chemistry Final Exam study guide
Vocab
Chapter 10:
Solid: rigid with a definite shape
Liquid : flowing matter with a definite volume
Gas: flowing, compressible matter with indefinite shape and volume
Brownian motion: the constant, random motion of tiny chunks of matter
Temperature: a measure of the average kinetic energy of the particles in the material
Evaporation: particles of a liquid form a gas, occurs at the surface of the liquid
Vaporization: particles of a liquid form a gas, occurs throughout the liquid and requires the addition of heat
Sublimation: particles of a solid escape and form a gas
Condensation: particles of a gas form a liquid
Boiling: temperature at which vaporization occurs
Freezing: particles of a liquid form a solid
Melting: particles of a solid form a liquid
Deposition: particles of a gas form a solid (snow)
Heat of vaporization: the energy absorbed when 1 kg of a liquid vaporizes at its boiling point
Heat of fusion: The energy released when 1 kg of a substance solidifies at its freezing point
Chapter 11:
Barometer: an instrument that measures air pressure
Boyle’s Law: As volume increases, pressure decreases. As volume decreases, pressures increases.
Charles’ Law: As temperature is increased, gases expand and volume increases. As temperature is decreased, gases condense and volume decreases.
Combined Gas Law: explains the relationship between volume, pressure and temperature:
P1V1 = P2V2
T1 T2
Chapter 13:
Dissociation: the process by which an ionic solid separates into + and – ions
Unsaturated solution: the amount of solute dissolved is less than the maximum amount that can be dissolved
Saturated solution: holds the maximum amount of solute per amount of solution
Supersaturated solution: contains more solute than the maxium, a solution is heated, solute is dissolved and then the solution is cooled
Osmosis: the flow of solvent molecules through a semi-permeable membrane from an area of high concentration to an area of low concentration
Colloid: a heterogeneous mixture that contains small particles suspended in a dispersing medium
Tyndall effect: the light-scattering effect of colloids
Emulsion: a colloid consisting of fine liquid droplets dispersed in a liquid medium (lotion)
Chapter 14
Acid: a substance that produces H+ ions in water
Acidic hydrogen: Any hydrogen ion that can be given off by an acid: HCl, HNO3, H2CO3
Ionization: ions forming from a covalent substance: H2O H3O+
Base: a substance that produces OH- ions in water
pH: a mathematical scale that represents the concentration of H+ ions expressed as a number from 0 to 14
Review questions
Chapter 10:
1. Compare the particle motion in a gas, liquid and solid.
Particles in a gas are moving freely in all directions and have the most kinetic energy. Particles in a liquid move past each other. Particles in a solid vibrate in place.
2. Convert 255oC to Kelvin.
255oC + 273K = 528K
3. Convert 600 Kelvin to Celsius.
600K – 273oC = 327oC
4. How is it possible to get water to boil at room temperature?
Lower the pressure
5. Why does food need longer to cook at high altitudes?
Air pressure is lower at high altitudes so water boils at a lower temperature. Because of this, food must be cooked for a longer period of time.
6. Describe how a pressure cooker speeds up cooking.
Due to the higher pressure, water boils at a higher temperature. Because of this, water cooks faster.
Chapter 11
7. Use Boyle’s Law: P1V1 = P2V2 to calculate the following: A 400L cylinder of oxygen gas is compressed at 150 atm. The oxygen must be administered at 3 atm. What volume can the oxygen occupy at this pressure?
(150 atm)(400L) = (3 atm) (V2)
V2 = (150 atm)(400 L) / 3 atm = 20,000L
8. Use Charles’ Law: V1/T1 = V2/T2 to calculate the following: A 4L sample of gas is collected at 30oC. What volume will it occupy at 0oC?
4L / (30oC + 273K) = V2 / (00C + 273)
V2 = (273K)(4L)/303K = 3.6L
9. Use the Combined Gas Law: P1V1/T1 = P2V2/T2: A 2.7L sample of nitrogen is collected at 121 kPa and 288K. If the pressure increases to 202 kPa and the temperature rises to 303K, what volume will the nitrogen occupy?
(121 kPa)(2.7L) / 288K = (202 kPa)(V2) / 303K
V2 = (121 kPa)(2.7L)(303K) / (288K)(202 kPa) = 1.7 L
10. The following are equivalent pressures: 1.00 atm = 760 mmHg = 14.7 psi = 101.3 kPa
Convert the following:
a. 600 mmHg to psi
600mmHg X 14.7psi = 11.6 psi
1 760mmHg
b. 8 psi to mm Hg
8 psi X 760 mmHg = 413.6 mmHg
1 14.7 psi
c. 20 psi to kPa
20 psi X 101.3 kPa = 137.8 kPa
1 14.7 psi
d. 200kPa to atm
200 kPa X 1.00 atm = 1.97 atm
1 101.3 kPa
11. How are pressure and volume related?
Inversely proportional
12. How are temperature and volume related?
Directly proportional
Chapter 13
13. What affect does solute have on the freezing point of a substance?
Solute decreases the freezing point (freezing point depression) because it prevents the particles of the substance from getting close together.
14. What affect does solute have on the boiling point of a substance?
Solute increases the boiling point of a substance (boiling point elevation) by preventing the molecules from reaching the surface and escaping.
15. How do temperature and pressure affect the solubility of gases?
Solubility of gases increases has pressure increases and temperature decreases. (put the cap back on the soda and place it in the fridge to prevent it from going flat)
Chapter 14
16. Label the following substances acid or base:
a. NaOH: base
b. H2C2O4: acid
c. NH3: base
d. H2SO4: acid
17. Identify the following acids as monoprotic, diprotic or tripotic:
a. H2SO4: diprotic
b. HF: monoprotic
c. H3PO4: triprotic
d. HC2H3O2: monoprotic
18. What characteristic distinguishes strong acids from weak acids?
Strong acids dissociate completely, weak acids do not.
19. Compare and contrast the properties of acids and bases.
Acids taste sour, bases taste bitter and feel slippery. Acids turn litmus red, bases turn litmus blue.
20. Describe the pH scale. Which values are acidic? Basic?
The scale goes from 0 to 14. Acids are below 7, 7 is neutral, bases are greater than 7 up to 14.
21. List some household items that are acidic and basic.
Citrus juices and fruit are acidic. Vinegar is acidic. Detergents and cleaners are mostly basic.
22. What is a pH indicator? How does it work?
pH indicators are chemicals that change colors in solutions of various pH.
23. What characteristic distinguishes strong bases from weak bases?
Strong bases dissociate completely, weak bases do not.
24. Describe how to perform a titration.
A solution of known concentration is used to determine the concentration of an unknown solution by measuring the volume it takes to neutralize the solution. (A pH indicator is used and a change of color is observed.)
25. In terms of [H+] and [OH-], distinguish between acidic, basic and neutral.
[H+] > [OH-] = acidic
[H+] < [OH-] = basic
[H+] = [OH-] = neutral
26. Solution A has a pH of 2. Solution B has a pH of 5. Which solution is more acidic? How many times more acidic?
Solution A is 1000 times more acidic than solution B.
27. What are the H+ concentrations for number 26?
Solution A = 1 X 10-2
Solution B = 1 X 10-5
28. What are the OH- concentrations?
Solution A = 1 X 10-12
Solution B = 1 X 10-9