General Chemistry Final Exam with Complete Solutions-, Exams of Advanced Education

Download General Chemistry Final Exam with Complete Solutions- and more Exams Advanced Education in PDF only on Docsity! General Chemistry Final Exam with Complete Solutions definition of thermochemistry - correct answer-branch of thermodynamics that deals with the evolution of absorption of energy as heat in chemical processes what is an everyday example of heat evolving from a chemical reaction - correct answer-burning of petroleum for energy what does the reaction system include? - correct answer-all the chemicals involved in the reaction what does the surrounding consist of? - correct answer-everything else, such as containers and the atmosphere what are the two ways in which energy can be transferred between a reaction system and its surroundings? - correct answer-either as work or as heat when does the system gain energy as work? - correct answer-when the work is positive when does the system lose energy as work? - correct answer-when the work is negative conversion of 1 L*atm to J - correct answer-1 L*atm = 101.325 J what is it called when the system transfers energy as heat to the suroundings - correct answer-exothermic what is the value of q and U in an exothermic reaction - correct answer-negative what is it called when the system gains energy as heat from the surroundings - correct answer-endothermic what is the value of q and U in an endothermic reaction? - correct answer-positive what does U stand for? - correct answer-the energy of a system what is the first law of thermodynamics? - correct answer-equivalent to the law of conservation of energy state functions - correct answer-functions that depend only on the state of a system, not on how that state is achieved what is the value of w when system is compressed? - correct answer-positive what is the value of w when system is expanded - correct answer-negative how do you calculate the energy released as heat - correct answer-1. balance equation and find changeH 2. finding limiting reactant 3. multiply moles of limiting reactant by changeH/mole how do you calculate change in Urxn when given equation and change Hrexn - correct answer-1. Fine change in moles of gas (coefficients) 2. multiply change by RT 3.subtract from change Hrxn what is the value of Change Hrxn when adding two equations - correct answer-add the two change Hrxn how to calculate changeHf - correct answer-Use hess's law how to find change Hrxn using bond energies - correct answer-(energy required to break bonds in reatants)-(energy evolved as heat upon formation of bonds in product) how to calculate change Hrxn using change Hf - correct answer-products change Hf - reactants change Hf how to calculate molar bond enthalpy using change Hf - correct answer-1. calculate change Hrxn using change Hf 2. divide by number of bonds definition of heat capacity - correct answer-energy in the form of heat required to raise the temperature of the sample by one degree what does qp=? - correct answer-change of H how to calculate heat capacity? - correct answer-heat energy/changeT how to calculate molar heat capacity - correct answer-heat capacity/moles how to calculate heat required to raise the temperature using molar heat capacity - correct answer-=(moles)(molar heat capacity)(changeT) definition of specific heat - correct answer-heat capacity per gram of substance how to calculate specific heat - correct answer-(heat capacity)/(mass) how does the temperature affect the rate of evaporation? - correct answer-higher the temp, higher the rate of evaporation how to tell how much vapor is condensed into liquid in container - correct answer-1. calculate pressure of gas 2. compare to equilibrium vapor pressure of the liquid 3. If pressure of gas is more, then gas condenses until pressures= each other how does intermolecular attractions affect vapor pressures? - correct answer-strong intermolecular attractions have low vapor pressures because they cannot overcome the attractive forces of other molecules to enter the vapor phase where is the normal boiling pyoint? - correct answer-where vapor pressure = external pressure how to find the energy required to disperse liquid through its surface tension - correct answer-energy = surface tensions * change in area crystallinity - correct answer-the degree of structural order in a solid unit cell - correct answer-smallest subunit of crystal lattice simple cubic - correct answer-one atom per unit cell (each corner 1/8 of atom) length of edge is 2r body-centered cubic - correct answer-two atoms per unit cell (each corner 1/8 of atom, 1 atom in middle) length of the main diagonal is 4r face centered cubic - correct answer-four atoms per unit cell (each corner 1/8 of atom, each face 1/2 atom) length of diagonal of a face is 4r how to calculate volume of a unit cel - correct answer-(#atoms*molecular weight)/(density*avagrado) types of solids - correct answer-ionic crystal, molecular crystal, network crystal, amorphous, metallic crystal atomic crystals - correct answer-particles of the same size ionic crystals - correct answer-held together by electrostatic attraction between ions of opposite charge molecular crystal - correct answer-crystals composed of neutral molecules network crystal - correct answer-extended network of covalent bonds metallic crystal - correct answer-Atoms in metals lose electrons to form cations. De- localized electrons surround ions in the electron cloud. Metallic bonds (electrostatic interactions between the ions and the electron cloud) hold the metallic solid together. Atoms are arranged like closely packed spheres. boiling point with respect to intermolecular forces - correct answer-higher the force, higher the boiling point colligative properties - correct answer-properties that depend on the ratio of the nuber of solute particles to the number of solvent molecules how to calculate molality - correct answer-(moles solute)/(amt of solvent in kgs) colligative molality - correct answer-(number of ions)*(molality) what is the difference between the vapor pressure of a solvent and that of a pure solvent - correct answer-the vapor pressure of the solvent will be less than that of the pure solvent because of the prescence of solute molecules at the surface of the solution decreases the number of solvent molecules per unit of area what is raoult's law - correct answer-vapor pressure of the solvent is directly proportion to the mole fraction of the solven raoult's law equation - correct answer-vapor pressure solute = vapor pressure solvent*mole fraction solute vapor pressure lowering - correct answer-the difference between the vapor pressure of the solution and the vapor pressure of the pure solvent which has a higher boiling point, pure solvent or solution and why - correct answer- solution because the equilibrium vapor pressure of a solution is less than that of a pures solvent, thus is requires a higher temperature for the vapor pressure to reach the atm pressure how to find boiling point of solution (dilute) - correct answer-(Tsolution-Tpure)=(boiling point constant(solvent)*(colligative molality solute) which has a lower freezing point, pure solvent or solution - correct answer-solution how to find freezing point of solution (dilute) - correct answer-(Tsolution- Tpure)=(freezing point constant(solvent)*molality solute) direction of osmosis - correct answer-from higher concentration to lower concentratoin how to calculate osmotic pressure (bar)? - correct answer-=R(bar)TMc colligative molarity = - correct answer-iM reverse osmosis - correct answer-when the pressure of lower concentration is higher than high concentration and flows to high azeotrope - correct answer-A mixture of two liquids that cannot be separated by distillation henry's law - correct answer-The concentration of a gas dissolved in a liquid at a given temperature is directly proportional to the partial pressure of the gas above the liquid how to solve for average rate of concentration change/rate of reaction - correct answer- change in concentration product/time how to take into consideration stoichimoetric coefficients in a rate of reaction calculation - correct answer-1/coefficient how to determine rate law of reaction - correct answer-(rate of reaction 1/rate of reaction 2) = (concentration 1/concentration 2)^x what does zero order indicate - correct answer-that the rate of the reaciton does not depend on how much of that reactant is available and an increase in decrease of that concentration does not affect the rate of reaction graph of first order reaction - correct answer-linear for ln[A] vs t how to find concentration after n half lives - correct answer-=(1/2)^n * initial concentration how to calculate half life for first order - correct answer-0.693/k particles in radioactive processes - correct answer-alpha, beta, gamma alpha particle effects - correct answer-4,2 He (mass number decreases by 4 and atomic number decreases by 2) beta particle effects - correct answer-0,-1 e (mass number does not change and atomic number increases by 1) gamma particle effects - correct answer-0,0 y (mass and atomic numbers do not change)