Chem 112 Exam #1 Complete Questions With Detailed Correct Answers

miscible - correct answers liquids that dissolve freely in one another in any proportion, no solubility limit (ie, water, ethanol) two ways to change solubility limit - correct answers change temperature, change pressure temperature - correct answers solids: deltaH 0, endothermic, ^ temp= ^ solubility limit, favors (aq): heat+solute(s) =solute(aq) gases: deltaH 0, exothermic, ^ temp decreases solubility limit, favors (s): solute(g) = solute(aq)+heat pressure - correct answers for gas dissolved in liquid/solid Henry's Law: c fish p; c=concentration of gas (opening a soda) collecting gas in bubbles decreases entropy, energetically unfavorable concentration units - correct answers amount solute present in given amount of solvent/soln percent concentration by mass - correct answers mass solute/mass soln x 100 mole fraction - correct answers X; moles of solute/sum moles of all componenets OR moles solute/moles soln molarity - correct answers M; moles solute/ L soln molality - correct answers m; moles solute/ mass solvent (kg) colligative properties - correct answers when you add a solute to a solvent to form a soln, all of the physical properties of the solvent change. depend only on the # of dissolved particles and not their nature Raoult's Law - correct answers delta VP = XP (X=mole fraction, P=pressure of solvent) enthalpy of soln (deltaH soln) - correct answers heat change associated with making a soln step 1 deltaH1: provide space w/in volume of solvent, breaking I.A., endothermic, 0 step 2 deltaH2: break solute, endothermic, 0 step 3 deltaH3: make I.A. b/t solute/solvent, exothermic, 0 entropy (s) - correct answers measure of the disorder of a system; increased disorder decreases the energy of the system (it costs energy to keep order) breaking up: S^ compressing: S decrease creating a soln/mixture: S^ solution - correct answers homogeneous (uniform) mixture mixture - correct answers combination of 2+ elements in varying ratios solute - correct answers dissolved in solvent solvent - correct answers present in greatest quantity in soln and is in the same state as the soln solid solutions - correct answers alloys gas solutions - correct answers mixture of gases; nitrogen is the solvent in air liquid solutions - correct answers advantageous in reactions (Alka Seltzer); serve as heat sinks heat sink - correct answers liquid solution that absorbs excess heat, such as in computer processors; can prevent explosions saturated solution - correct answers contains the maximum amount of a solute that will dissolve in a given solvent at a specific temperature unsaturated solution - correct answers contains less solute than the solvent has the capacity to dissolve supersaturated solution - correct answers contains more solute than is present in a saturated solution. Unstable: solute separates for brief periods of time, so still considered part of the solution solution process - correct answers "like dissolves like" ie, intermolecular attractions dissolve the same intermolecular attractions solubility limit - correct answers maximum amount of solute that will dissolve in a given amount of solvent ionic solids - correct answers held together by electrostatic attraction b/t cations/anions, from ionic compounds. Ionic force is stronger than that of a molecular solid: hard, brittle, medium melting pt (NaCl) covalent network solids - correct answers entire solid held together by covalent bonds, like one large molecule. Very hard, strong, high melting pt (grpahite, diamond, silica, quartz) molecular solids - correct answers held together by weak intermolecular attractions, formed from molecular compounds. Soft, low melting pt (paraffin in candles) metallic solids - correct answers held together by metallic bonding- 3D covalent bonding. formed from metal elements, conduct electricity. Hard, strong, medium melting pt metallic bonding - correct answers 3D covalent bonding, electrons are shared in all directions, not just in line across 2 atoms solid-- liquid - correct answers melting or fusion- melting parts of solid fuse into one liquid liquid-- solid - correct answers freezing, solidification liquid-- gas - correct answers boiling, vaporization, evaporation gas--liquid - correct answers condensation