AP Chem: States of Matter – Flashcards

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question
What is the pressure exerted by 5 moles of gas in a 40 L container at 300 K?
answer
Using the ideal gas equation, you can calculate the pressure exerted by the gas is about 3.1 atm.
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How many atoms of a substance are in 1 mole of that substance?
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In 1 mole of a given substance, there are                   6.022 x 1023 atoms.
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On the periodic table, the masses given for the elements are masses for what quantity of the element?
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The masses given for the elements are for 1 mole of the element. 
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Polar substance will only dissolve what other type of substances?
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Other polar substances
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In order for a solvent to dissolve a solute, what must be overcome? 
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In order for a solvent to dissolve a solute, intermolecular forces must be overcome. 
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What is the freezing point depression equation?
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Tfkf msolute
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  1. Physical Change
  2. Chemical Change
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  1. Substance changes form or state only. Boiling, melting, freezing, dissolving, grinding, cutting
  2. Where new substances are formed with new chemical and physical properties. Oxygen and hydrogen form water; sodium and chlorine form salt (sodium chloride)
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List the three states if matter in order of increasing density
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Gas: neither definite shape nor volume

 

Liquid: definite volume; takes shape of container

 

Solid: definite size and shape

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Phase

Two examples

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A sharply defined, uniforme region in a mixture.

 

Examples- oil and vinegar in salad dressing; ice and water in a frozen pond

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Density

General equation and three standard units

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The mass of a unit volume of a substance.

 

Density = mass/volume

 

g/mL g/L kg/L

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Calculate the density of a rock with mass = 10g and volume = 5mL
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Density = mass/volume

 

density 10 g/5 mL = 2 g/mL

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Element

List some examples

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A substance composed of identical atoms.

 

gold, silver, oxygen, hydorgen, lead, chlorine, helium, iron, copper, fluorine, arsenic

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Compound

List some examples

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Substance composed of two or more different elements chemically combined. For example:

Water - H2O

Salt - NaCl

Sugar - C6H12O6

Ammonia - NH3

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Mixture

List some examples

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A combination of substaces held together by physical means.

(Dirt, milk, soup, saltwater, granite)

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Homogenous ang heterogenous Mixture

Give example

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Homogeneous mixtures are uniforme in composition. (Air, metal, alloy, salt water)

Hetergeneous mixtures are not uniform in composition. (Dirt, spaghetti sauce)

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Symbols for:

  1. Barium
  2. Beryllium
  3. Platinum
  4. Arsenic
  5. Tin
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  1. Ba
  2. Be
  3. Pt
  4. As
  5. Sn
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Symbols for:

  1. Sodium
  2. Potassium
  3. Calcium
  4. Hydrogen
  5. Magnesium
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  1. Na
  2. K
  3. Ca
  4. H
  5. Mg
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Names for:

  1. Fe
  2. Co
  3. Ni
  4. Cu
  5. Zn
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  1. Iron
  2. cobalt
  3. Nickel
  4. Copper
  5. Zinc
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Symbols for:

  1. Silver
  2. Gold
  3. Mercury
  4. Aluminum
  5. Lead
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  1. Ag
  2. Au
  3. Hg
  4. Al
  5. Pb
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Names for:

  1. C
  2. Si
  3. N
  4. P
  5. O
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  1. Carbon
  2. Silicon
  3. Nitrogen
  4. Phosporous
  5. Oxygen
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Symbols for:

  1. Sulfur
  2. Fluorine
  3. Chlorine
  4. Bromine
  5. Iodine
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  1. S
  2. F
  3. Cl
  4. Br
  5. I
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Names for:

  1. He
  2. Ne
  3. Ar
  4. Kr
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  1. Helium
  2. Neon
  3. Argon
  4. Krypton
  5. Uranium
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Einstein's law of conservation of energy
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The sum-total of mass and energu remains constant in a reaction but mass and energy may be interconverted.

E = mc2

E= energy; m = mass

c= speed of light

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Identify as element, compound, or mixture

Sand, air, gold, water, salt, hydrogen

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Sand - mixture

Air - mixture

Gold - element

Water - compound

Salt - compound

Hydrogen - element

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  1. Physical Properties
  2. Chemical properties
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  1. Properties which can be observed without changing the substance into something different. Color, odor, hardness, density, luster, state, conductivity, solubility, boiling and melting points.
  2. A chemical property is observed when a substance changes into a new substance. Iron forms rust in air and water; gasoline burns in oxygen.
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PRESSURE

Write Normal Atmospheric Pressure in Five Standard Units

;

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Pressure is force per unit of area

;

1 atmosphere= 760 torr

= 760 mm Hg

= 101.3 kilopasca;s

= 14.7 pounds/square inch

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  1. Barometer
  2. Manometer
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  1. An instrument, invented by torricelli in 1643, which measures atmospheric pressure. An evacuated glass tube in which a column of mercury rises or falls with change in pressure.
  2. An instrument used to measure pressure of gases in a closed container.
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State three postulates of:

The Kinetic

Molecular

Theory of gases

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  1. Matter is composed of very small particles; a gas is mostly empty space.
  2. Particles are in constant random motion.
  3. Collisions are elastic
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State the formula for Graham's Law of Diffusion.Do heavy or light gases diffuse faster?

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A mixture of a gas A & B:

(RA)(MWA)1/2 = (RB)(MVB)1/2

MWA,MWB = Molecular weights

RA, RB = Rates of Diffusion

(Light gases diffuse faster)

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Charles' Law

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V1/T1 = V2/T2

Pressure and amount of gas are constant

V = volume

T = Kelvin

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At 300 K a gas has a volume of 10 liters. Find the volume at 400 K

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Use Charles' Law,

V1/T1 = V2/T2

10/300 = V2/400

V2 = 13.3 L

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Boyle's Law

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P1;x V1 = P2 x V2

Pressure and volume are inverse if temperature and amount of gas are constant

P = pressure

V = volume

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A sample of gas has a volume of 23 L at 800 torr. find the volume at 400 torr.

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Use Boyle's Law

P1 x V1 = P2 x V2

25 x 800 = 400 x V2

V2 = 50 L

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Combined Gas Law
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P1V1/T1 = P2V2/T2

Amount of gas is constant

P = pressure

V = volume

T = kelvin

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Dalton's Law of Partial Pressure

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In a gas mixture, the total pressure equals the sum of the partial pressures of each component

Ptotal = P1 + P2 + P3 ...

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Ideal Gas Law

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PV = nRT

P = pressure (Atmospheres)

V = volume (Liters)

n = # of Moles

R = 0.0820 L-ATM/MOL-K

T = temperature in K

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How many moles of H2 gas are there in 20 L at 4 atm and 400 K?

answer

Use the Ideal Gas Law

PV = nRT

;

(4 atm)(20 L) = n(0.082)(400)

n = 2.44 moles

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  1. STP
  2. Gay-Lussac's Law of Combining Gas Volume
answer
  1. Standard temperature (0° C or 273 K) and standard pressure (1 atmosphere or 760 torr)
  2. When only gases are involved in a reaction, the volumes of reactants and product are in a small, whole number ratio.
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  1. Avogadro's Law (regarding gases)
  2. What is the volume of 1 mole of any gas at STP
answer
  1. Under the same conditions of temperature and pressure; equal volumes of gases contain equal numbers of moles.
  2. 22.4 L
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N2 + 3H2 ; 2NH3

In the above reaction how many L of NH3 will be produced from 6L H2

;

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According to Gay-Lussac's Law the volumes of gases are in direct proportion to the coefficients in the equation.

H2 : 3/6 L = NH3 : 2/x

x = 4L of ammonia

 

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Sublimation

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The change from a solid to a vapor without the forming of a liquid

Compounds which show sublimation

(CO2, I2)

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Describe a phase change from liquid to gas

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When a molecule gains enough kinetic energy to overcome the intermolecular attractive forces within a liquid, it escapes the surface and becomes gas.

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  1. Phase equilibrium
  2. Dynamic equilibrium
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  1. For a liquid in a closed container; when the rates of evaporation (liquid to gas) and condesation (gas to liquid) equalize: the concentration of each is stable.
  2. In a closed container where opposing changes are taking place at equal rates; the concentration of all components remains constant.
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Normal Boiling Point

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The temperature at which a liquid phase becomes a gas phase when vapor reaches atmospheric pressure.

Pressure = 1 atm

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Define:

  1. Critical temperature
  2. Critical pressure
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  1. The temperature above which the liquid phase of a substance can no longer exist.
  2. Minimum pressure required to liquify a gas at its critical temperature
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Melting Point

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The temperature at which the solid and liquid phases co-exist

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  1. Heat of fusion (value for water)
  2. Heat of vaporization (value for water)
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  1. The amount of energy required to change a gram of substance from liquid at its melting point. (Water - 80 calories/gram)
  2. The amount of energy required per gram to change a liquid to gas at its boiling point. (Water - 540 calories/gram)
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  1. Triple point
  2. Vapor pressure
answer
  1. The only temperature and pressure combination at which the 3 phases of a substance (solid, liquid and gas) can co-exist at equilibrium
  2. The pressure the gas phase exerts on its liquid phase in a close container. This pressure varies with temperature.
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Define boiling point in terms of vapor pressure

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The temperature at which the vapor pressure over a liquid reaches atmospheric pressure. The substance boils (liquid to gas)

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  1. How much heat is required to change 10 grams of water to steam at 100° C
  2. How much heat is required to melt 0.5 grams of ice at 0° C
answer
  1. Heat of vaporization of water is 540 cal/g

10g x 540 cal/g = 5400 cal

 

2. Heat of fusion of water is 80 cal/gram

(0.5 grams)(80 cal/gram) = 40 cal

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