Gases and Their Properties 4. The kinetic molecular theory describes the motion of atoms and molecules and explains the properties of gases. As a basis for understanding this concept: a. Students know the random motion of molecules and their collisions with a surface create the observable pressure on that surface. b. Students know the random motion of molecules explains the diffusion of gases. c. Students know how to apply the gas laws to relations between the pressure, temperature, and volume of any amount of an ideal gas or any mixture of ideal gases. d. Students know the values and meanings of standard temperature and pressure (STP). e. Students know how to convert between the Celsius and Kelvin temperature scales. f. Students know there is no temperature lower than 0 Kelvin. g.* Students know the kinetic theory of gases relates the absolute temperature of a gas to the average kinetic energy of its molecules or atoms. h.* Students know how to solve problems by using the ideal gas law in the form PV = nRT. Using , H2 + O2 H2O, how many grams of water could form from the reaction of 64.0g of O2? A)10.0g B)36.0g C)64.0g D)72.0g E)None of the above What causes a gas to expand when it is heated? A. The particles in the gas move around faster and spread out. B. The gas becomes bigger. C. Particles in a high temperature state rise up and push the low temperature ones down. D. The actual particles themselves swell so that the whole gas becomes larger when heated. Why does a gas decrease in pressure when the container it is in becomes larger? A. A larger container causes the particles of gas to hit the boundaries less often, therefore they exert less pressure. B. The particles slow down when the container increases in size, therefore causing the particles to hit the walls with less force. C. Because the particles swell and become heavier, so that they move slower and hit the boundaries less often. D. Some gas always escapes when a container expands and therefore, the pressure inside goes down. At absolute zero, which best describes the motion of all gas particles? A. B. C. D. They become absolutely still. They turn into ice. They disappear. They become very cold and frost grows on top of the atoms. What is the temperature of a metal at 435OC in the Kelvin scale? A.162 K B. 567 K C.708 K D.1.59 K E. 312 K What are the values for STP? A.273OC and 1 atm B. 0 K and 1 atm C.0 OC and 1 atm D.273 K and 360 mmHg A 30ml cylinder changes from 27OC to 127OC, what will the cylinder’s new volume be if pressure remains constant? A.15ml B. 40ml C.630ml D.75ml E. None of the above The air in the room is at 25°C and has a pressure of 101kPa. How many moles of gas are in the room, if the room has a volume of 20 dm3? (R = 8.31) A. B. C. D. 230.0 mol 1.61 mol 0.816 mol 76.0 mol What is the volume of 2 moles of methane gas at STP? A.22.4 L B. 470.0 L C.11.2 L D.44.8 L Acids and Bases 5. Acids, bases, and salts are three classes of compounds that form ions in water solutions. As a basis for understanding this concept: a. Students know the observable properties of acids, bases, and salt solutions. b. Students know acids are hydrogen-ion-donating and bases are hydrogen-ion-accepting substances. c. Students know strong acids and bases fully dissociate and weak acids and bases partially dissociate. d. Students know how to use the pH scale to characterize acid and base solutions. e.* Students know the Arrhenius, Bronsted-Lowry, and Lewis acid-base definitions. f.* Students know how to calculate pH from the hydrogen-ion concentration. What is not a property of Bases? A. B. C. D. Feel Slippery Sour in taste Conduct an electric current Form a salt and water when combined with an acid E. All of the above According to Brønsted-Lowry, acids and bases are: A. Acids contain hydrogen ions and bases contain hydroxide ions. B. Acids are proton donors and bases are proton acceptors. C. Acids accept electron pairs and bases donate electron pairs. An unknown solution in the lab has a pH of 13, which best describes the solution? A.A B. A C.A D.A E. A strong acid weak acid neutral solution strong base weak base What happens when equal amounts of a 1M acid and a 1M base are mixed? A. The solution is neutralized. B. A salt and water are formed. C. The [H3O+] and [OH-] are equal. D. All of the above E. Both A and B When a strong acid or base are mixed with water they separate fully into separate ions, this process is called: A.Disintegration B. Degeneration C.Dissolution D.Dissociation E. None of the above An acid solution has a hydronium concentration of [H3O+] = 0.001M, what is the pH of the solution? A.1 B. 2 C.3 D.4 E. 5 Solutions 6. Solutions are homogenous mixtures of two or more substances. As a basis for understanding this concept: a. Students know the definitions of solute and solvent. b. Students know how to describe the dissolving process at the molecular level by using the concept of random molecular motion. c. Students know temperature, pressure, and surface area affect the dissolving process. d. Students know how to calculate the concentration of a solute in terms of grams per liter, molarity, parts per million, and percent composition. 10g of Sodium Chloride is added to 100ml of water, which is the solute? A.Water B. Sodium Chloride C.Water and Sodium Chloride D.Both A and C How does water dissolve a polar solute? A. By surrounding the charges of the solute with the positive and negative poles of the water molecules. B. By filling the gaps between the molecules C. Water does not dissolve polar solutes. D. Water gets broken down into H+1 and OH-1 and these attach to the charges of the polar solute Heating a solid solute helps the dissolving process by: A. Melting the solute therefore creating a liquid that mixes easily with the solvent B. Spreading the molecules away from each other so empty spaces are filled C. Increasing the speed of the solute therefore increasing the collisions D. All of the above Which of the following is not a way to increase the rate at which a solid solute dissolves? A. Stirring B. Crushing the solute first C. Adding pressure D. Increasing the temperature 1.5 mol of CuCl2 are dissolved into 50L of water, what is the Molarity of solution? A.75.0 M B. 3.0 M C.0.03 M D.0.75 M Explain why heating a gas solute will not help it dissolve. A. Because the gas molecules are too small to be affected by the increase in heat. B. Because the gas molecules are too hard to stir and heating is just like stirring on the molecular level. C. Gas molecules move faster when heated and this causes them to move out of the solution so they don’t dissolve. D. Gas molecules are lower in energy than water, therefore when the gas molecules are heated they have an increase in their total enthalpy of dissolution which requires an increase in the molecular status. Chemical Thermodynamics 7. Energy is exchanged or transformed in all chemical reactions and physical changes of matter. As a basis for understanding this concept: a. Students know how to describe temperature and heat flow in terms of the motion of molecules (or atoms). b. Students know chemical processes can either release (exothermic) or absorb (endothermic) thermal energy. c. Students know energy is released when a material condenses or freezes and is absorbed when a material evaporates or melts. d. Students know how to solve problems involving heat flow and temperature changes, using known values of specific heat and latent heat of phase change. Which of the following is the best description of the temperature of a substance? A. The temperature is the average kinetic energy of the individual particles in the substance. B. The temperature is best described as how hot a substance is. C. The temperature is the total amount of kinetic energy from all of the particles in a substance. D. Temperature is best defined as the absence of cold. E. None of the above When a reaction releases energy (in other words energy is a product) this reaction can be described as: A. B. C. D. E. Endothermic Exothermic Either condenses or freezes Both B and C None of the above How much energy is needed to raise the temperature of 10g of water from 20OC to 40OC? A.200.0 J B. 836.8 J C.2510.4 J D.418.4 J E. None of the above What is the ΔHvap for water? A.334 J/g B. 4.184 J/g OC C.2260 J/g D.1 cal/g OC How much energy does it take to get 260g of water at its freezing point to solidify? A. B. C. D. E. 587600 J 86840 J 1087.8 J 3340.6 J None of the above Reaction Rates and Chemical Equilibrium 8. Chemical reaction rates depend on factors that influence the frequency of collision of reactant molecules. As a basis for understanding this concept: a. Students know the rate of reaction is the decrease in concentration of reactants or the increase in concentration of products with time. b. Students know how reaction rates depend on such factors as concentration, temperature, and pressure. c. Students know the role a catalyst plays in increasing the reaction rate. d.* Students know the definition and role of activation energy in a chemical reaction. 9. Chemical equilibrium is a dynamic process at the molecular level. As a basis for understanding this concept: a. Students know how to use LeChatelier's principle to predict the effect of changes in concentration, temperature, and pressure. b. Students know equilibrium is established when forward and reverse reaction rates are equal. c.* Students know how to write and calculate an equilibrium constant expression for a reaction. The Reaction rate for a chemical reaction relies on: A. The decrease in reactants conc. and the increase in products conc. B. A change in temperature, pressure, and surface area. C. The presence of a catalyst D. All of the above Describe how adding pressure to solid reactants effects the rate of reaction? A catalyst increases the rate of a reaction by: A. Increasing the speed of individual particles so they hit harder. B. Breaks the reactants into smaller pieces. C. Lowering the activation energy. D. Telling the reactants to react together. E. Both C and D Describe how adding pressure will increase the rate of a reaction for a gas reactants? Which factor does not effect the equilibrium of a reaction? A. B. C. D. E. Temperature Catalyst Pressure Concentration None of the Above In a sealed bottle that is half full of water, equilibrium will be attained when water molecules A. Cease to evaporate B. Begin to condense C. Are equal in number for both the liquid and the gas phase D. Evaporate and condense at equal rates In the reaction: N2 + 3H2 2NH3 Where would the equilibrium shift if Pressure is increased? A. B. C. D. Left The side with the more moles of gas The side with the least moles of gas Both A and B What is the formula you would use to calculate the Equilibrium constant of a reaction? Draw a Heat curve and label where a liquid, a gas, and freezing occurs Zn (s) + 2HCl (g) H2 (g) + ZnCl2 (aq) + HEAT Write the Equilibrium expression/constant for the above reaction. Zn (s) + 2HCl (g) H2 (g) + ZnCl2 (aq) + HEAT What would happen to the equilibrium if H2 gas is removed? Zn (s) + 2HCl (g) H2 (g) + ZnCl2 (aq) + HEAT What would happen to the equilibrium if the reaction is placed on ice? Zn (s) + 2HCl (g) H2 (g) + ZnCl2 (aq) + HEAT What would happen to the equilibrium if the volume the reaction is in increased? Why does a more concentrated solution react at a faster rate? A hot piece of Iron is placed into a tub of water at room temp. Which one losses energy? In Thermochemistry, which term is used to describe a reaction that is cold in temperature. 2Na + Cl2 2NaCl If 3.64 moles of Na is reacted with an excess of chlorine gas, how many moles of NaCl will be produced? A. 1.28 mol B. 3.64 mol C. 7.28 mol D. 10.92 mol 2H2 + O2 2H2O If 8 g of oxygen reacts with an unlimited amount of hydrogen, how many grams of water will be produced? A. 9 g B. 16 g C. 18 g D. 36 g A mass of 5.4 grams of aluminum (Al) reacts with an excess of copper (II) chloride (CuCl2 ) in solution, as shown below. 3CuCl2 + 2Al 2AlCl3 + 3Cu What mass of solid copper (Cu) is produced? A. B. C. D. 0.65 g 8.5 g 13 g 19 g Which statement best describes the density of an atom’s nucleus? A. The nucleus occupies most of the atom’s volume but contains little of its mass. B. The nucleus occupies very little of the atom’s volume but contains little of its mass. C. The nucleus occupies most of the atom’s volume but contains most of its mass. D. The nucleus occupies very little of the atom’s volume but contains most of its mass. D Which part of the atom has the least amount of mass? A. B. C. D. electron cloud nucleus neutrons proton A How many outer shell electrons (valence electrons) does iron have? 2 Draw the Lewis electron dot diagram for nitrogen. N Elements X has the following electron configuration: 1s22s22p63s23p64s23d104p65s24d105p6. Which of the following describes this element? A. unstable metal B. unstable nonmetal C. stable metal D. stable nonmetal D Which of the following elements has the largest radius? A.F B.Br C.As D.N E.S C Where are the alkali earth metals? 2nd Group If aluminum becomes an ion, does it become larger or smaller? Smaller – it lost electrons (3+) What is Nuclear Fusion? When a nucleus breaks down into smaller ones An isotope of uranium emits a particle composed of two protons and two neutrons. What remains after the isotope emits the particle? A. a new element that has a mass smaller than the uranium mass B. a new element that has a mass greater than the uranium mass C. a new isotope of uranium that has a mass greater than the starting mass D. a new isotope of uranium that has a mass smaller than the starting mass A What are the three types of nuclear decay? Alpha, beta, gamma How is a positive ion formed? By losing electrons What element is in group 4 and period 5? A. Magnesium B. Zirconium C. Vanadium D. Boron B If a circuit for a light bulb is bridged by a glass of pure water, what will happen? A. B. C. D. The light bulb will glow because water conducts electricity The light bulb wont glow because the water needs to have ions Hard to say it depends on the temperature of the water Only if a catalyst is available will it light B Ionic materials are best described as: A. Gaseous masses with weak interparticle forces B. Solids made of atoms sharing electrons in order to complete the valance shells of the participating elements C. Solids made of a repeating pattern of ions held by electrostatic forces D. Liquids that have weaker intermolecular bonds so that the molecules can easily pass each other. C Which of the following best explains how covalent bonding occurs? A. Atoms exchange electrons forming positive and negative ions B. Metals share electrons forming molecules C. Nonmetals share electrons forming molecules D. Marvin Gaye plays “Let’s get it on” and the atoms tumble into each others arms. C Which of the following elements is filling the “s” sublevel? A. B. C. D. Cu Fe Ca Ne What family is Bromine in? If the unbalanced equation is: C3H8 + O2 → CO2 + H2O, then what is the best whole number ratio between the propane and the oxygen. A. B. C. D. E. 1 1 3 3 8 to to to to to 5 1 8 2 2 A The mole is best defined as: The number of hydrogen atoms in a water molecule B. The number of carbon atoms in 12g of carbon-12 C. The mass of a single atom D. The number of atoms it takes to get the molar equivalent of an atoms mass B A. What is the molar mass of sodium hydroxide, NaOH? 40 g/mol How many moles is 46.5g of sodium hydroxide? A)1860mol B).860mol C)40.0mol D)1.16mol E)None of the above D What is the molar mass of (NH4)2Cr2O7? 252 g/mol How many grams of (NH4)2Cr2O7 are in 5.50mol of ammonium dichromate? 1386 g If a room at STP has 300L of CO in it, how many grams of carbon monoxide are in the room? 375 g What type of chemical reaction always produces carbon dioxide and water? Combustion What is ionization energy? Energy needed to take 1 electron away from an atom Why do metals create different colors when heated? The electrons get excited, jump to a higher level, fall back down and release the energy