Chemistry Final Exam Test Yourself

Definitions When a stress is added to a chemical reaction at equilibrium, the reaction shifts so as to relieve the stress (Le Chatelier’s Principle) This lowers the activation energy of a reaction (Catalyst)

The actual steps that occur in a chemical reaction (Reaction Mechanism) A chemical reaction is this if it occurs naturally (Spontaneous)

A reaction which takes in heat energy; product has more potential energy (+∆H) (Endothermic) A reaction which gives off heat energy; product has less potential energy (-∆H) (Exothermic)

The kinetic energy necessary for a chemical reaction to occur (Activation Energy) When the maximum amount of solute has dissolved in a solvent at a specific temperature; increases with temperature (Saturated Solution)

A measure of the energy of disorder in a substance (Entropy) A measure of the potential energy associated with a substance (Enthalpy)

A chemical reaction is at this when the concentrations of reactants and products remain constant. (Forward reaction rate = Reverse reaction rate.) (Equilibrium) Branch of chemistry that can be used to determine how fast a reaction occurs (Kinetics)

The branch of chemistry that can be used to determine whether or not a reaction is spontaneous (Thermodynamics) The pressure that sits over any liquid (Vapor pressure)

The total pressure is equal to the sum of the individual pressures (Dalton’s Law of Partial Pressures) Moles of solute per kilograms of solvent (Molality)

A measure of the maximum amount of solute dissolved in a solvent at a given temperature (Solubility) A homogenous mixture (Solution)

20% there! A substance that is dissolved (Solute) A substance that dissolves another (Solvent) Disorder is increasing in the universe (2 nd Law of Thermodynamics)

A substance that changes color in an acidic or basic environment (Indicator) A molecule that accepts an H+ ion (Base)

A molecule that donates an H+ ion (Acid) Used to indicate concentration (moles/liter) (Molarity)

A molecule is this when the atoms in it share electrons. Composed of non-metals (Covalent) A compound is this when the atoms in it give or take electrons. Composed of at least one non-metal and one metal (Ionic)

Short Answer What are the 4 factors that affect the rate of a reaction? (Concentration, surface area, temperature, and adding a catalyst) As the number of ions increases in a solution, the ____________ goes down (Freezing point)

As the number of ions increases in a solution, the ____________ goes up (Boiling point) If the equilibrium constant (K) is much less than one, are there more products or reactants at equilibrium? (reactants)

If the K a for an acid is much greater than one, is it a strong or weak acid? (strong) Which gas law includes pressure, volume, temperature, and the # of moles? (Ideal Gas Law – PV = nRT)

Whose law states that as the temperature of a gas increases, the volume also increases? (Charles’) Whose law states that as the pressure of a gas increases, the volume decreases? (Boyles)

What are 4 units of pressure? (atm, torr, mm Hg, kPa) State the geometrical shape and whether the following is purely covalent or polar covalent: CCl 4 (Tetrahedral, purely covalent)

If the central atom in a molecule pulls unevenly on the surrounding electrons, what type of molecule is it? (polar covalent) What must be negative for a reaction to be spontaneous? (∆G)

What theory states that electron pairs in a molecule are as far apart from one another as possible? (VSEPR – Valence Shell Electron Pair Repulsion) The change in enthalpy (  H) is negative for what type of reaction? (Exothermic)

Which of the following substances contains the greatest amount of disorder (S)? A. 1.0 mole of CO 2 (s) B. 1.0 mole of CO 2 (l) C. 1.0 mole of CO 2 (g) D. 0.5 mole of CO 2 (s) (C)

Which of the following pH values is indicative of a strong acid? A. pH B. pH C. pH D. pH (A)

An ____________ reaction that ________ entropy will always be spontaneous. (exothermic; increases) Which is the acid and which is the base in the following: H 2 CO 3 + H 2 O → HCO H 3 O + ? (acid – H 2 CO 3 ; base – H 2 O)

2NO + I 2 → 2NOI This reaction is 2 nd order with regard to NO and 1 st order with regard to I 2. What is the rate equation? (R= k[NO] 2 [I 2 ] ) For the following reaction, N 2 (g) + O 2 (g) ↔ 2NO (g), the equilibrium constant at a particular temperature is The concentrations of each substance are the following: [N2] = 0.5 M, [O2] = 1.7 M, [NO] = M. Which way will the reaction shift so as to achieve equilibrium? (Q = 1.2 x 10-4 Reaction will shift to the right)

Which arrow represents the activation energy of the catalyzed reaction? (6) Which arrow represents the heat of reaction (∆H)? (2) Which arrow represents the activation energy for the uncatalyzed reaction? (1) Is the forward reaction exo- or endothermic? Is ∆H neg. or positive? (exothermic; ∆H neg)

More than half-way! 2 SO 2 (g) + O 2 (g) ↔ 2 SO 3 (g) + energy Which way would increasing the temp shift this reaction at equilibrium? (to the left) Which way would decreasing the [SO 3 ] shift this reaction at equilibrium? (to the right) Increasing the pressure? (to the right)

A ______ ______ is used in galvanic cells to maintain charge balances between the 2 half-cells. (salt bridge) What is the electrolyte in lead-acid (car) batteries? (sulfuric acid)

What is the oxidation number of Chromium in CrO 4 2- ? (+6) Zn + 2MnO 2 + 2NH Cl - → Zn 2+ Mn 2 O 3 + 2NH 3 +2Cl - + H 2 O What is the reducing agent? Oxidizing agent? (Zn – reducing agent; MnO 2 – oxidizing agent)

What is the oxidation number of carbon in H 2 C 2 O 4 ? (+3) What is the formula for carbon disulfide? (CS 2 )

Fe(s) + Ni2+(aq) → Fe2+(aq) + Ni(s) What reaction is taking place at the anode? (Fe(s) → Fe2+ (aq) + 2e- ) What reaction is taking place at the cathode? (Ni2+(aq) + 2e- → Ni(s) Where is the nitrate ion going? (to the anode) Where is the K+ ion going? (to the cathode)

What is the formula for calcium carbonate? (CaCO 3 ) What is the formula for iron III oxide? (Fe 2 O 3 ) What is the formula for dinitrogen monoxide? (N 2 O)

Which of the following conducts electricity? CO 2, Ne, Ag, CCl 4 (Ag) What is the molecular geometry of CO 2 ? (linear) What type of bond exists in H 2 ? (purely covalent)

Acids taste ___, donate__ ions. sour H + sour H + Bases taste__, accept __ions, donate __ions, denature___. bitter H + OH - protein bitter H + OH - protein In a neutral solution, [H + ] is ___[OH - ]. In an acidic solution, [H + ] ____ [OH - ]. In a basic solution, [H + ] is ____ [OH - ]. (equal to; greater than; less than)

What is the concentration of 20.0 g of NH 3 dissolved in 130 mL of water? (6.5 M) A(n) ____ in temperature will help a solute that dissolves endothermically dissolve. (increase)

A solution is a _______ mixture. (homogeneous) If a saturated solution at 80 o C is cooled to 25 o C, what will happen? (a precipitate will form)

When you drink from a straw, you _____ the pressure inside the straw allowing the ______ ______ to push the liquid up. (decrease; atmospheric pressure) When you heat up a gas in a closed container, what happens? (temperature increased; pressure increased)

1 atm = _____ mm Hg (760) Walking up a hill is an example of a ________ process; rolling a rock down a hill is an example of a _______ process. (nonspontaneous; spontaneous)

List in order of least entropy to most entropy: 1 mol H 2 O(l), 1 mol H 2 O(g), 1 mol H 2 O(s) (solid – liquid – gas) An endothermic reaction feels ___ to the touch. An exothermic reaction feels ___ to the touch. (cold; hot)

What is the catalyst in the following:? 2NO(g) + O 2 (g) → 2NO 2 (g) 2NO 2 (g) + SO 2 → 2SO 3 (g) + 2NO(g) (NO(g)) Predict what will happen to the rate of a reaction if “x” has the following values: 0, 1, 2 (no change; double; quadruple)

A homogeneous catalyst is in the same _____ as one of the reactants; heterogeneous, different ______ than any of the reactants. (phase; phase) Most household spills are ____; most cleaners are _____. (acidic; basic)

You have a stock solution of 18 M H 2 SO 4 and would like to make mL of 3.0M acid. How would you do it? (take 417 (420 SF) mL of water and add 83 mL of 18 M H 2 SO 4 ) What are the six strong acids? Everything else is _________! (HBr, HI, HCl, H 2 SO 4, HClO 4, HNO 3 ; weak)

In a gas mixture of H 2, He and Ar, the total pressure is 90.3 kPa. The partial pressure of Ar is 40.7 kPa, and the partial pressure of He is 5.1 kPa. What is the partial pressure of H 2 ? (44.5 kPa) The_______ ____ is when the vapor pressure of a liquid is equal to atmospheric pressure. (boiling point)

A gas has a volume of 20.0 L at 100. o C and 500. mm Hg. What is its new volume at 60. o C and 700. mm Hg? (13 L) Gasoline and water do not mix because gasoline is _____ and water is ______. (purely covalent; polar)

2 SO 2 (g) + O 2 (g) ↔ 2 SO 3 (g) What is the equilibrium constant for the above reaction? (K = [SO 3 ] 2 (click one more time) [SO 2 ] 2 [O 2 ] What is always true when a reaction is at equilibrium? [rate of forward rxn = rate of reverse rxn – NOT that the concentrations of the products and reactant are ALWAYS equal (only when K = 1)]

Under which of the following conditions would you expect gases to behave ideally? A. T = 100 K, P = 1.0 atm B. T = 300 K, P = 1.9 atm C. T = 150 K, P = 1.0 atm D. T = 273 K, P = 0.5 atm (D)

Almost there!!! When iron oxidizes, what is it called? (Oxidation, rusting, corrosion) If a reaction gets hot, it is an ________ rxn and _________ heat to/from the surroundings. (exothermic; releases… to)

A strong acid or base dissociates ___________ into its constituent ions in an aqueous solution. (Completely!) CONGRATULATIONS!!! YOU’RE DONE!!!!!!