Exambusters Study Cards 13 Solutions – Flashcards
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Unlock answersMolarity (State general equation) |
The number of moles of solute in a liter of solution.
M=n/L
M= molarity; n = moles; L = liters |
Solute |
The substance dissolved in another (solvent). Salt is the solute in salt water. |
Solvent |
A substance, usually a liquid, into which another substance (solute) is dissolved. Water is the solvent in iced tea. |
Solution (Give an example) |
A liquid, gas, or solid phase containing two or more components uniformly dispersed.
e.g. air, coffee, saltwater |
Calculate the molarity when 5 moles of NaCl is dissolved in 25 liters of water. |
M = n/L
M = 5/25 M = 0.2M |
Calculate the moles of NaCl in 5 liters of a 2 molar solution. |
M = n/L 2 M = n/5 L 10 = moles of NaCl |
Acid anhydride |
Non-metallic oxides which, when reacted with water, form acid solutions. e.g. CO2 + H2O → H2CO3 SO3 + H2O → H2SO4 |
Basic anhydride |
Metallic oxides which, when reacted with water, form basic solutions. e.g. Na2O + H2O → 2 NaOH CaO + H2O → Ca(OH)2 |
Why is water a good solvent for ionic compounds? |
Due to hydrogen bonding, water is polar. The negatively charged oxygen attracts a cation, and the positively charged hydrogen, an anion. |
Solubility Curves |
A curve for a given substance which shows how much dissolves in a given amount of solvent at different temperatures. |
How do temperature and pressure affect the solubility of a solid? |
Solubility usually increases with increasing temperature. Pressure has little effect. |
How do temperature and pressure affect the solubility of a gas? |
Solubility usually decreases with increasing temperature. Solubility in creases in direct proportion to an increase in pressure. |
Which three factors affect the rate of solubility? |
pulverizing stirring heating |
What is a general rule for solubilities of polar and nonpolar compounds? |
"Like dissolves like." Ionic and polar solvents dissolve ionic, polar solutes. e.g. Water dissolves salt.
Nonpolar solvents dissolve nonpolar solutes. e.g. Acetone dissolves gasoline and cooing oil. |
Solubility of nitrates, acetates, and chlorates in water. |
All are soluble |
Solubility of Na, K, and (NH4)+ compounds in water. |
All are soluble. |
Solubility of chlorides in water. |
All chlorides are soluble, except Ag, Hg, Pb. |
Solubility of sulfates in water. |
All sulfates are soluble, except Pb, Ba, Sr, Ca |
Solubility of carbonates, phosphates, sulfides, and silicates in water. |
All insoluble, except Na, K, (NH4)+ |
Solubility of hydroxides (OH-) in water. |
All insoluble except Na, K, (NH4)+, Ca, Ba, Sr |
Hydrated ion |
A dissolved ion which is surrounded by water molecules. It is attracted electrostatically to the polar water molecule. |
Miscible |
Two liquids which dissolve in each other. e.g. water and alcohol |
Immiscible |
Two liquids which do not dissolve in each other. e.g. oil and vinegar |
Brownian Movement |
When light is shone through a colloid, the individual zig-zag paths of the particles in the dispersing medium can be observed; like smoke in a dark theater. |
Basic facts about Solutions |
particle size less than 1 nanometer. Clear (may be colored) )articles don't settle Can pass through membranes Particles not visible |
Basic facts about colloids |
particles measure 1-1000 nanometers Particles don't pass through a membrane Show Brownian movement and the Tyndall effect Particles don't settle Clear Pass through filter paper |
Basic facts about Suspensions |
No Brownian movement Don't pass through filter paper or a memebrane Cloudy, but particles settle on standing Particles visible with microscope or eye |
Dilute |
Small amount of solute in the solvent. |
Concentrated |
Large amount of solute in the solvent. |
Saturated |
In the presence of undissolved solute, the solution is holding all the solute possible at that temperature. |
Unsaturated |
More solute can be dissolved in the solvent at that temperature. |
Supersaturated |
Created by cooling a saturated solution. If cooled slowly, the solute stays dissolved. The amount of solute in the solution is greater than the solubility at a given temperature. |
Write the equation for percent concentration of a solute in a solution (mass/mass). |
% concentration = (gsolute/gsolution)(100%) |
HOw many grams of NaCl are required to prepare 500 g of a 5% solution? |
% Conc. = (gNaCl/gsolution)(100%) 5% = (x/500 g)(100%) 25 g NaCl = x |
Molality |
The number of moles of solute dissolved in 1 kg of solvent. molality (m) = moles solute/kg solvent |
Calculate the molality of 10 moles of H2SO4 dissolved in 4 kg of water. |
molality = moles solute/kg solvent = 10/4 = 2.5 molal |
Gram-equivalent weight |
The amount of substance which reacts with or displaces one mole of H+ ions. |
Normality |
The number of gram-equivalent weights in a liter of solution. |
Wire the equation for molarity changes related to diluting a solution. |
(M1)(V1)= (M2)(V2)
M = molarity V = Volume |
10 liters of a 6 molar solution is diluted to 3 molar. What is the final volume? |
(M1)(V1)= (M2)(V2) (6)(10) = (3) (V2) V2 = 20 L |
Colligative Properties |
Properties of solutions that depend primarily on the concentration of solute and not on the type of particle. |
List three basic colligative properties of solutions. |
vapor pressure lowering boiling point elevation freezing point depression |
In H2O solutions how many °C is the freezing point depressed for each molal of solute? |
1.86 °C for each molal of particles of solute |
In H2O solutions how many °C is the boiling point elevated for each molal of solute? |
0.51 °C for each molal of particles of solute |
Hydrated crystal |
A crystal that holds a definite proportion of water in its structure |
Crystal |
In a crystal structure, ions or atoms form a repeating pattern of unit cells. |
List six basic types of unit cells which can make up crystal lattices. |
Simple cubic face-centered cubic body-centered cubic tetragonal hexagonal monoclinic |
efflorescent |
Hydrated crystals which lose their water of hydration on exposure to air at room temperature. e.g. magnesium sulfate |
deliquescent |
Hydrated crystals which absorb water from the air and become wet. e.g. calcium chloride and magnesium chloride |
anhydrous crystal |
A hydrated crystal which loses its water of hydration. The pure salt loses the crystal structure and crumbles to powder |
Unit cell |
The smallest portion of a crystal lattice that is repeated throughout the crystal |