Solutions Exam 1

Question 1

solution

Answer 1

composed of a solute and solvent, each of which can be a solid, liquid or gas

Question 2

Molarity (M)

Answer 2

amount of solute(moles) / volume of solution (L)

Question 3

Mass Percent

Answer 3

(mass of solute / mass of solution) x 100

Question 4

Volume Percent

Answer 4

(volume of solute / volume of solution) x 100

Question 5

Mass Volume Percent

Answer 5

(mass of solute (g) / volume of solution (mL)) x 100

Question 6

Parts Per Blank

Answer 6

ppm (parts per million) = mg solute / L solution

or: (g solute / g solution) x 1,000,000

ppb (x10^9)
ppt (x10^12)

Question 7

Mole Fraction (Xi) and Percent

Answer 7

Xi = moles of i / total solution moles

mole percent = 100(Xi)

Question 8

Molality (m)

Answer 8

independent of temperature unlike molarity

amount of solute (moles) / mass of solvent (kg)

Question 9

Normality (N)

Answer 9

(# of equivalents)(Molarity)

Question 10

Solubility

Answer 10

amount of solute that can be dissolved in a solvent

= grams of solute dissolved / given mass or volume of solvent

increases with temperature (with few exceptions)

Question 11

miscible

Answer 11

ability of 2 compounds to homogeneously mix in a solution

-like dissolves like (ex: polar: water, ionic, salts, alcohols, water-soluble compounds; or nonpolar: hydrocarbons, molecular compounds, oils, gasoline, grease, fat, fat-tissue, many organics)

Question 12

enthalpy of solution (delta H soln)

Answer 12

energy involved in mixing a solute and solvent to form a solution

delta H soln > 0 (+) endothermic and feels cold
delta H soln < 0 (-) exothermic and feels hot

Question 13

ideal solution

Answer 13

when delta H soln = 0 (occurs for hydrocarbon (organic) mixtures)

Question 14

Saturated

Answer 14

The saturated line represents the point where dissolution and crystallization are both occurring and in equilibrium with each other

Question 15

Undersaturated

Answer 15

region of the graph occurs when the solvent can dissolve more solute than is available (located on bottom part - kind of where gases would be)

Question 16

Supersaturated

Answer 16

occurs when solution has more solute in solutions than equilibrium allows.

Question 17

Fat-soluble

Answer 17

compounds that are essentially nonpolar; recognized for being composed of mostly C and H atoms and possibly one OH group. (Ex: Vitamin A)

Question 18

Water-soluble

Answer 18

compounds that are polar; recognized for having numerous OH groups (polar) along with C and H atoms (ex: Vitamin C)

Question 19

Temperature Effects: Solids dissolved in liquids

Answer 19

solubility increases as temperature increases

Question 20

Temperature Effects: Gasses dissolved in liquids

Answer 20

solubility of gas in liquid decreases as temperature increases

Question 21

Pressure Effects: (Gases dissolved in Liquids)

Answer 21

As pressure increases, the solubility of gas in liquid increases.

Question 22

Henry’s Law

Answer 22

Describes pressure effects of pressure increasing - solubility of gas in liquid increases.

C = kPgas

• C: solubility or concentration
• k: henry’s law constant (sometimes 1/k)
• Pgas: pressure of the gas

Sometimes written as:
k = C1/P1 = C2/P2

Question 23

Raoult’s Law

Answer 23

Describes why adding a solute to a solvent causes the solvent to have a lower vapor pressure (or partial pressure, Pa). The partial pressure (Pa) is equal to the mole fraction (Xa) multiplied by the pure pressure of the solvent.

Combine Dalton’s law if question asks about vapor pressure. Dalton’s: Ptot = XaPa^o + XbPb^o

Question 24

Negative deviation

Answer 24

Mixture of polar molecules

Question 25

Positive deviation

Answer 25

Mixture of nonpolar and polar molecules

Question 26

Fractional distillation

Answer 26

When separating mixtures, fractional distillation is used in stages to distill, separate out the liquid, condense the vapor, and re-distill.