Exambusters Study Cards 13 Solutions – Flashcards
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Unlock answers| Molarity (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 |
