Chemistry Hnrs. Final Exams

Be able to solve for the mass percent or volume percent of a solute in a particular solution (Ch.16)

(%(v/v))=vol. of solution/vol. of solution x 100% ex. What is the percent by volume of ethanol (C2H6O)in the final solution when 85 mL of ethanol is diluted to a vol. of 250mL w/ water? %vol=vol. solute/total vol.; 85 mL/250mL x 100% = 34% (%(m/m))=mass of solute/mass of solution x 100%

Be able to calculate the the molar heat of a reaction using both Hess's law of summation and the molar enthalpy of formation for reactant/products in the eq.(Ch.17)

(Heat)H0=Hf0(products)-(Heat)Hf0(reactants) ex. C(s, graphite) + O2(g)-->CO2(g) (heat)H=-393.5 kJ C(s, diamond)+O2(g)--->CO2(g) (heat)H=-395.4 kJ CO2(g)---->C(s, graphite) + O2(g) (heat)H=-395.4 kJ C(s,diamond)+O2(g)-->CO2(g) (heat)H=-395.4 kJ CO2 (g)-->C(s,graphite) + O2(g) (heat)=393.5 kJ (Cancel out CO2/O2) C(s,diamond)--->C(s, graphite) (heat)H=-1.9kJ

Using collision theory, identify what factors can effect the rate of a reaction ~continued~(Ch.18)

(Temp.-raise temp, speeds reaction; lowering slows down)(conc.-# of particles in a given vol. affects the rate @ which reactions occur; more particles crammed-increases conc./frequency of collision leading to higher reaction rate ) (Particle size- Total surface area of a solid/liquid, reactant affects rate. Smaller particle size, larger surface area of mass particles) (Catalysts-lowers activation energy; increases the rate of reaction w/o being used up during reaction)

Balancing Chemical Equations(Ch.11)

A chemical equation must be balanced to indicate the quantity of reactants needed to make the product, otherwise it'd be unstable: ex. SnO2 + H2 → Sn + H2O (add 2 to H) SnO2 + H2 → Sn + 2 H2O SnO2 + 2 H2 → Sn + 2 H2O (now add 2 to balance both H2's) Answer: SnO2(s) + 2 H2(g) → Sn(s) + 2 H2O(g)

What are the main differences between nuclear and chemical eq.? (Ch. 25)

A nuclear reaction involves the splitting of nuclei, usually producing something unstable and releasing neutrons. After a nuclear reaction, a process of emitting radiation (alpha beta and gamma) occurs for it to gain stability. A chemical reaction is where atoms bond with each other to gain stability.

What is Stoichiometry? (Be able to determine mole ratios from a balanced chemical eq.) (Ch.12)

A subject in chemistry that is the calculations of quantities in chemical reactions. ex. 3Fe(s)+4H2O(g)--->Fe3O4(s)+4H2(g) How many moles of H2(g) can be produced when 3 moles of Fe3 react? # mol H2(g)=3mol Fe(s) x 4mol H2 (g)- -------- = 4mol H2(g) 3 mol Fe (s)

Be able to complete and balance nuclear reactions involving beta decay, alpha decay, positron emission, and electron capture

Alpha- 238/92U-----> 234/90 Th + 4/2He(alpha) Beta- 1/0n--->1/1H + 0/-1 e(beta) Gamma (no mass/no charge)

What is an activation barrier and how does it determine if a chemical reaction will occur or not? (Ch.18)

An activation barrier is the point which reactants have to pass in order to for it to become a product. If the reactants have enough activation energy to pass this activation barrier,it will react.

Identifying general reactants/products that participate in each type of eq. ~continued~

An element/compound are the reactants in a single replacement reaction. A different element and a new compound are the products.

What are endothermic and exothermic processes? Describe how the conservation of energy dictates the relationship of heat flow between a system and its surroundings. Also know the mathematical sign convention for endothermic/exothermic reactions (Ch.17)

An endothermic process is one that absorbs heat from its surroundings. In an endothermic process, the system gains heat as the surroundings cool down. An exothermic process is one that releases heat into its surroundings. In an exothermic process, the system loses heat as the surroundings heat up. The law of conservation of energy states that in any chemical or physical process, energy is neither created/destroyed

Be able to compare and contrast the following definitions of acids and bases: Arrhenius, Bronsted-Lowry, and Lewis. If given a simple eq., be able to identify acid/base present using these definitions

Arrhenius said that acids are hydrogen-containing compounds that ionize to yield hydrogen ions (H+) in aq. solution (H+ producer). He also said that bases are compounds that ionize to yield hydroxide ions (OH-) in aq. solution (OH- producer)

Know eq. for Boyle's, Charles', Gay Lussac's, and the combined Gas law (Be able to identify which gas law must be used & correctly use the the eq. to solve problem) (Ch.14)

Boyle's Law- P1 x V1= P2 x V2; Charles' Law- V1/T1=V2/T2; Gay Lussac's law- P1/T1=P2/T2; Combined Gas Law- P1 x V1/T1=P2 x V2/T2

Be able to conduct calculations using the specific heat capacity eq.(Ch.17)

C=q/m(triangle of Heat) x T=Heat(j/g x C) or cal/g x C)/mass (g) x change in temp. (C) ex. How much heat is required to raise temp. of 250.0g of Mercury 52degrees C? (250.0g)(.14g/C)(52C)=1820=1.82kJ d

What is a thermochemical eq.? If given such an eq., be able to calculate the heat absorbed/evolved in a reaction for a specific mass of procduct/reactant (Ch.17)

Chemical eq that includes the enthalpy change. ex. Calculate the amount of heat (in kJ)required to decompose 2.24 mol NaHCO3(s); 2NaHCO3(s)+129 kJ-->Na2CO3(s)+H2O(g)+CO2(g) (triangle)H=129kJ; 2molNaHCO3/129kJ=2.24mol/x kJ; x=144.5kJ

Identify the five primary classes of Chemical Eq. (If given a generic equation, identify what type of reaction it is using the type and # of elements reacting) ~continued~(Ch.11)

Combination Reaction- chemical change in which two or more substances react to form a single new substance (always have 1 product in a combination reaction) x+y-->xy ex. 2Mg(s)+O2(g)-->2MgO(s)

Identify the five primary classes of Chemical Eq. (If given a generic equation, identify what type of reaction it is using the type and # of elements reacting) ~continued~(Ch.11)

Combustion Reaction- chemical change in which an element/compound reacts oxygen often producing energy in the form of heat/light. element w/ carbon+ O2 -->CO2(g)+H2O(g) ex. 2C8H18(l)+25O2(g)-->16CO2(g)+18H2O(l)

Identify the five primary classes of Chemical Eq. (If given a generic equation, identify what type of reaction it is using the type and # of elements reacting) ~continued~(Ch.11)

Decomposition Reaction-Chemical change in which a single compound breaks down into two or more simpler products ex. 2HgO(s)--> 2Hg(l)+O2(g) ex. 2HI-->H2(g)+I2(s)

Identifying general reactants/products that participate in each type of eq. ~continued~(Ch.11)

Decomposition reaction-single compound-reactant; 2 or more substances are the products.

Identify the five primary classes of Chemical Eq. (If given a generic equation, identify what type of reaction it is using the type and # of elements reacting)(Ch.11)

Double-Replacement Reaction - an exchange of positive ions between two compounds ab+cd--> ad+bc (always have two ionic compounds as reaction) ex.Ba(NO3)2 (aq) +H3PO4(aq)-->Ba(NO3)2+H3PO4---> Ba3(PO4)2+6NHO3

Identifying general reactants/products that participate in each type of eq. ~continued~(Ch.11)

Double-replacement reaction, two ionic compounds are the reactants; two new compounds are the products.

Use mole ratios to complete sotichiometric calculations to determine the amount of one substance in a chemical reaction(mol, L, g, molecules) from initial amt of 2nd substance (mol, L, g, molecules)(Ch.12)

Ex. How many moles of glucose C6H12O6 are consumned when 3 mol of CO2 are produced? C6H1206(s)+6O2(g)-->6 CO2(g)+6H2O(l) moles of C6H12O6=3mol CO2 x 1mol C6H12O6 -------- = 0.5moles 6 mol CO2

Describe the sequence of events that occurs in nuclear fission and fusion. Be able to compare and contrast the two

Fission is the splitting of the nuclei into smaller fragments. In a chain reaction,some of the neutrons produced react with other fissionable, producing more neutrons which react with still more fissionable atoms. Fusion is when nuclei combine to produce a nuclei of greater mass. Fusion reactions, in which small nuclei combine, release much more energy than fission reactions, in which large nuclei split. Both exert much energy

What is free energy and entropy? Use Gibbs free energy to calculate/determine if a given chemical process is spontaneous(Ch.18)

Free energy is energy available to do work. Entropy is a measure of the disorder of a system; (triangle)G(free energy)=(triangle)H(enthalpy)-T(temp.) x (triangle)S(entropy) (triangle)H=-, (triangle)S=+ encourage rxn to be spontaneous

Ideal Gas Law (correctly use the eq. to solve problems) (Ch.14)

Ideal Gas Law- PV=nRT, R=8.31(L x kPa)/(K x mol) P- Pressure R=8.31(L x kPa)/(K x mol) V-Vol. n-moles T-Temp.

What is the difference between a real/ideal gas?Under what conditions do real gasses deviate from ideal behavior? (Ch.14)

Ideal Gas- follows the gas law @ all conditions temp./pressures, conforms precisely to the assumptions of the kinetic theory, its particles has no volumes, and there could be no attraction between particles in the gas, there is no gas for which these assumptions are true, ideal gas does not exist

What are endothermic and exothermic processes? Describe how the conservation of energy dictates the relationship of heat flow between a system and its surroundings. Also know the mathematical sign convention for endothermic/exothermic reactions ~continued~(Ch.17)

If the energy of the system decrease during that process, the energy of the surroundings must increase by the same amount so that the total energy of the universe remains unchanged. 1 Calorie=1 kilocalorie=1000calories

Be able to calculate the equilibrium constant for an eq. and determine whether the foward or reverse reaction is favored @ equilibrium (Ch,18)

Keq=[C]c x [D]d /[A]a x [B]b *a value of Keq greater than 1 means that products are favored over reactants; a value of Keq less than 1 means that reactants are favored over products

What is chemical equilibrium? Using LeChatalier's principle, identify if a specific change in chemical equilibrium would favor the forward/reverse reaction in a reversible chemical process. ~conitnued~ (Ch.18)

Le Chatalier's principle: if a stress is applied to a system in a dynamic equilibrium, the system changes in a way that relieves the stress. Stresses that upset the equilibrium of a chemical system include changes in the conc. of reactants, products, changes in temp., and changes in pressure.

Be able to compare and contrast the following definitions of acids and bases: Arrhenius, Bronsted-Lowry, and Lewis. If given a simple eq., be able to identify acid/base present using these definitions

Lewis Proposed that an acid accepts a pair of electrons during a reaction(electron-pair acceptor), while a base donates a pair of electrons(electron-pair donor)

Know the eq. for molarity and use it to solve for liters, moles, or molarity ~continued~(Ch.16)

M=mol solute/L solution; ex. Household Laundry bleach is a dilute aqueous solution of sodium hypochlorite (NaClO).How many moles of solute are present in 1.5 L of 0.70M NaClO? M=7, V=1.5L, mol=?, mol=M(L); mol solute=0.70mol NaClO/1 L x 1.5L= 1.1mol NaClO

Be able to calculate the freezing point depression and boiling point elevation of a liquid if given the relevant information (calculating molality)(Ch.16)

Molality (m)=mol solute/kg solvent; freezing point (triangle)T=Kf x mf, boiling point-(Triangle) Tb=Kb Ex. Antifreeze protects a car from freezing. It also protects it from overheating. Calculate the freezing-point depression and the freezing point of a solution containing 100 g of ethylene glycol (C2H6O2) antifreeze in 0.500kg of water. moles C2H6O2= 100g C2H6O2 x 1mol/62.0 g C2H6O2=1.62 mol; m=mol solute/kg solvent=1.61 mol/0.500kg=3.22m (triangle)Tf=Kf x m= 1.86 degreesC/m x 3.22m=5.99C, 0.00-5.99=5.99C

Know the eq. for molarity and use it to solve for liters, moles, or molarity (Ch.16)

Molarity (M)=moles of solute/liters of solution. ex. One saline solution contains 0.90g NaCl in exactly 100mL of solution. What is the molarity of the solution? solution concentration=0.90g NaCl/100mL x 1 mol/58.5 g NaCl x 1000mL/1L= 0.15 mol/L=0.12 M

What is Net Ionic Equation and Spectator ion? (Why can certain ions be eliminated from chemical equations)? (Ch.11)

Net ionic eq.-eq. for a reaction in solution that shows only those particles that are directly involved in the chemical change ex. Ag+ (aq)+Cl-(aq)--->AgCl(s) Spectator ion- an ion that appears on both sides of an eq./isnt directly involved in the reaction *Net ionic eq. shows only those particles involved in the reaction and is balanced w/ respect to both mass/charge

Conceptually describe how volume, temperature and number of moles effect gas pressure~continued~ (Ch.14)

Number of moles- you can use kinetic energy theory to predict and explain how gases will respond to a change of conditions. If you inflate an air raft, for example, the pressure inside the raft will increase. Collisions of particles w/ the inside walls of the raft result in the pressure that is exerted by the enclosed gas. By adding gas, you increase # of particles. Increasing # of particles increase number of collisions (gas pressure increases);Basically-> More molecules=More collisions=more force=high pressure

What is partial pressure? (How do you use Dalton's law of partial pressures to calculate the pressure of a gas in a mixture)? (Ch.14)

Partial pressure- contribution of each gas in a mixture makes to the total pressure. In a mixture of gases, the total pressure is the sum of the partial pressures of the gases. P total= P+P+P...

What is Percent yield and Theoretical yield? Actual yield? (Be able to calculate all 3 of these values if given data from a chemical process) (Ch.12)

Percent Yield- The ratio of the actual yield to the theoretical yield expressed in a percent; Theoretical yield-maximum amount of product that could be formed from given amount of reactants; Actual yield- amount of product that actually forms when the reaction is carried out in the laboratory percent yield= actual yield -------------- x 100% Theorectical yield

How do changes in temp./pressure affect the solubility of the liquid and gaseous solutes? (Ch.16)

Pressure:Changes in pressure have little effect on solubility of solids and liquids, but strongly influences the solubility of gases. Gas solubility increases as the partial pressure of the gas above the solution increases. At higher temps. kinetic energy of molecules is greater than at lower temp. so they move faster.

Identify what each term in a rate law represents. From a rate law eq., how do you knowif a given reaction is slow or fast?(Ch.18)

Rate=k[A]a[B]b; The value of the specific rate constant, k, is large if products form quickly,The value's small if products form slowly

What is the difference between a real/ideal gas?Under what conditions do real gasses deviate from ideal behavior? ~continued~(Ch.14)

Real Gas- Behave much like an ideal gas w/ their temp./pressure, particles do not have vol., there are atttractions between the particles, can condense or even solidify because of these attractions when they are compressed/cooled. Real gases differ from an ideal gas at low temp./high pressure

Limiting Regeant (Be able to computationally determine limiting regeant, given amounts in grams, liters, moles of 2/more regeants in a reaction)(Ch.12)

Regeant that determines the amount of of product that can be formed by a reaction.*You must calculate the amount of product each reactant makes whichever reactant makes less product is the limiting regeant

Identify the five primary classes of Chemical Eq. (If given a generic equation, identify what type of reaction it is using the type and # of elements reacting) ~continued~(Ch.11)

Single Replacement reaction-Chemical change in which one element replaces a second element in a compound z+xy--->zy+x ex. Zn(s)+Cu(NO3)2 (aq)-->Cu(s)+Zn(NO3) (aq)

Be able to explain the difference between strong and weak acids/bases

Strong acids are completely ionized in aq. solutions, weak acids ionize only slightly in aq. solution. Strong bases dissociate completely into metal ions and hydroxide ions in aq. solution. Weak bases react with water to form hydroxide ions and the conjugate acid of the base *Stronger the acid, larger Ka value

Identifying general reactants/products that participate in each type of eq. (Ch.11)

The # of elements and/or compounds reacting is a good indicator of possible reaction type and thus possible products. Combination reaction- 2/more reactants (elements/compounds)combine to form a single product An element/compound are the reactants in a single

Be able to compare and contrast the following definitions of acids and bases: Arrhenius, Bronsted-Lowry, and Lewis. If given a simple eq., be able to identify acid/base present using these definitions

The Bronsted-Lowry theory defines an acid as a hydrogen-donor (H+Donor), and a base as an hydrogen ion acceptor (H+acceptor)

Describe the relationship between molar heat fusion and solidification, and between vaporization/condensation. Be able to calculate exact quantities of heat involved in a phase change if given the appropriate molar enthalpy value ~continued~(ch.17)

The amount of heat necessary to vaporize one mole of a given liquid is called its molar heat of vaporization (triangle)Hvap.)The amount of heat released when 1mol of vapor condenses at the normal boiling point is called its molar heat of condensation(triangle)Hcond.) The quantity of heat absorbed by a vaporizing liquid is exactly the same as the quantity of heat released when the vapor condenses(triangle) Hvap.=-(triangle)Hcond.)

What are the 3 factors which affect the rate @ which a solute dissolves ? (How do you know if a solute is likely to be soluble in a particular solvent)? (Ch.16)

The compositions of a solute and the solvent will determine whether a substance will dissolve. Stirring (agitation), temperature, and the surface are of the dissolving particles determine how fast the substance will dissolve.

Describe the relationship between molar heat fusion and solidification, and between vaporization/condensation. Be able to calculate exact quantities of heat involved in a phase change if given the appropriate molar enthalpy value (ch.17)

The heat absorbed by one mole of a solid substance as it melts at a constant temperature is the molar heat of fusion (triangle)Hfus). The molar heat of solidification (triangle Hsolid) is the heat lost when one mole of a liquid solidifies at a constant temp. the quantity of heat absorbed by a melting solid is exactly the same as the quantity of heat realeased when the liquid solidifies (triangle Hfus.=-(Triangle)Hsolid.

What is Enthalpy? (Be able to conduct calculations involving enthalpy) (Ch.17)

The heat content of a system at a constant pressure. q sys.=(triangle)H= -qsurr.= -m x C x (triangle)T

What force holds the nucleus together?Explain why nuclei become unstable and radioactive decay, paying special attention to the band of stability

The nuclear force is the attractive force that acts between all nuclear particles that are extremely close, such as protons and neutrons in a nucleus. If a force does not hold these subatomic particles together the like-charged protons would repel one another and fly apart; The neutron-to-proton ration determines the type of decay that occurs

Using collision theory, identify what factors can effect the rate of a reaction (Ch.18)

The rate of a chemical reaction depends upon temp., concentration, particle size and use of a catalyst.According to collision theory, atoms, ions and molecules can react to form products when they collide w/ one another, provided that the colliding particles have enough kinetic energy.

Identifying general reactants/products that participate in each type of eq. ~continued~ (Ch.11)

The reactants in a combustion reaction are oxygen and usually hydrocarbon; products of most combustion reactions-carbon dioxide and water

How do you write proper chemical formulas in a skeleton equation when told which chemicals are getting produced? (Ch.11)

The reactants of the equation are typically on the left-hand side of the equation and the products are on the right-hand side. To make the equation complete, you need to solve for the correct coefficients for each of the chemicals, which indicate the relative amounts of each (Formulas of Reactants to the left of the arrow while products to the right)

Conceptually describe how volume, temperature and number of moles effect gas pressure (Ch.14)

Volume - you can raise the pressure exerted by a contained gas by reducing its volume. The more gas is compressed, the greater is the pressure than the gas exerts inside the container; when volume is halved, pressure is doubled

What is chemical equilibrium? Using LeChatalier's principle, identify if a specific change in chemical equilibrium would favor the forward/reverse reaction in a reversible chemical process.(Ch.18)

When rates of the forward and reverse reactions are equal, the reaction has reached a state of balance called chemical equilibrium. At chemical equilibrium, no net change occurs in the actual amounts of the components of the system.

Given Ksp for a salt, calculate the concentration of ions at equilibrium (Ch.18)

ex What is the concentration of lead ions in a saturated lead chromate solution @ 25C? (Ksp=1x10^-13) PbCrO4(s)<--->Pb2+(aq)+CrO4 2-(aq); Ksp=[Pb2+][CrO2-] 1.8x10^-14=[x][x]=x^2-->(sq. rt. 1.8x10^-14) x=1.3 x 10^-7 Pb2+ CrO4 2- since equilibrium = x, [Pb2+]=1.3x10^-7 I 0 0 C +x +x E x x

Know eq. for Boyle's, Charles', Gay Lussac's, and the combined Gas law (Be able to identify which gas law must be used & correctly use the the eq. to solve problem) ~continued~ (Ch.14)

ex. A balloon contains 30.0 L of helium gas @ 103 kPa. What is the vol. of helium when balloon rises to altitude where pressure is only 25.0 kPa? (Assume that the temp. remains constant) (Use Boyle's Law) We need to Find vol. : V2=V1 x P1/P2; V2=30.0L x 103 kPa/25.0 kPa = 1.24 x 10^2 L

Know eq. for Boyle's, Charles', Gay Lussac's, and the combined Gas law (Be able to identify which gas law must be used & correctly use the the eq. to solve problem) ~continued~ (Ch.14)

ex. A balloon inflated in a room @ 24degrees C has a vol. of 4.00L. The Balloon is then heated to a temp. of 58degrees C. What is the new vol. if pressure remains constant? (new vol.=V2); T1-24 degrees C+273=297 K; T2-58 degrees C + 273= 331 K; V2=V1 x T2/T1, V2=4.00L x 331 K/297 K= 4.46 L

Ideal Gas Law (correctly use the eq. to solve problems) ~continued~(Ch.14)

ex. A child's lungs can hold 2.20 L. How many grams of air do her lungs hold @ a pressure of 102 kPa and a body temp. of 37 degrees C? Use a molar mass of 29g for air, which is ~20% O2 (32 g/mol) & 80% N2 (28g/mol). P=nRT; n=?, V=2.20 L, T=37 degrees C +273=310 K, R=8.31 (L x kPa)/(K x mol), P=102 kPa; n= PV/RT, n=102 kPa(2.20 L)/8.31 (kPa x L)/(mol x K) (310 kPa)= .087mol x 29 g/1mol = 2.5 g

Be able to calculate the equilibrium constant for an eq. and determine whether the foward or reverse reaction is favored @ equilibrium ~continued~(Ch.18)

ex. A liter of gas mixture at equilibrium at 10C contains 0.0045 of N2O4 and 0.030 mol of NO2. Write the expression for the equilibrium constant and calculate the equilibrium constant (Keq) for the reaction K= [NO2]^2/[N2O4]=.03/.0045= .2

If given one of the following, be able to convert it into any one of the other three: [H+],[OH-],pH, pOH (Ch.19)

ex. Calculate pH or [H+] for each solution- b.pH=13.20 pOH,pH,H+,OH- [H+][OH-] pH=-log[H+] 10^-13=6.31x10^-14 pH+pOH=14 10-ph=[H+]

Describe the relationship between molar heat fusion and solidification, and between vaporization/condensation. Be able to calculate exact quantities of heat involved in a phase change if given the appropriate molar enthalpy value ~continued~(ch.17)

ex. How many grams of ice @ 0 degrees C will melt if 2.25 kJ of heat are added? Hfus=6.01 kJ/mol,H=2.25, m ice=?g; 6.01kJ/1mol H2O=2.25kJ/x mol, x= .37mol x 18g/1mol=6.7g ex. How many kJ of heat are required to melt a 10.0g popsicle @ 0degrees C? Assume the popsicle has the same motor mass/heat of fusion as water; 10g H2O x 1mol/18g=.56mol 6.01kJ/1mol H2O= x kJ/.56mol, x =3.4kJ

Use the realtion M1V1=M2V2 to conduct calculations involving the dilution of solutions(ch.16)

ex. How many mL of aqueous 2.00M MgsSO4 solution must be diluted with water to prepare 100.0mL of aqueous 0.400M MgSO4? V1=M2V2/M1=0.400M x 100.0mL/2.00M=20.0mL,Thus 20.0 mL of the initial solution must be diluted by adding enough water to increase the volume to 100.0mL

Limiting Regeant (Be able to computationally determine limiting regeant, given amounts in grams, liters, moles of 2/more regeants in a reaction)~continued~ (Ch.12)

ex. The eq. for the complete combustion of ethene (C2H4) is C2H4+3O(g)-->2CO2(g)+2H2O(g); If 2.70 mol C2H4 is reacted with 6.30 mol O2, identify the limiting regeant. 2.70 mol C2H4-->mol H2O; 6.3 mol O2-->mol H2O #1. 2.7mol C2H4 x 2mol H2O --------- = 5.4 mol H2O 1 mol C2H4 #2. 6.3mol O2 x 2mol H2O --------- = 4.2 mol H2O 3 mol O2 So, O2 is limiting reagent

Know eq. for Boyle's, Charles', Gay Lussac's, and the combined Gas law (Be able to identify which gas law must be used & correctly use the the eq. to solve problem) ~continued~ (Ch.14)

ex. The gas used in an aerosol can is @ a pressure of 103 kPa @ 25degrees C. If the can is thrown into the fire , what will the pressure be when the temp. reaches 928 degrees C? (add 273 to temp.'s); P2=T2 x P1/T1, P2= 103 kPa x 1201K/298 K= 415 kPa= 4.15 x 10^2 kPa

Be able to conduct calculations using the specific heat capacity eq. ~continued~(Ch.17)

ex. The temp. of a 95.4-g piece of copper increases from 250C to 48.0 C when the copper absorbs 849 J, what is specific heat of copper? Mcu=95.4g,(triangle)T=(48.0C-25.0C)=23.0C, q=849J Ccu=?J/(gxC) Ccu=q/M(triangle)T= 849J/95.4g (23.0C)= 0.387 J/(g x C)

Know eq. for Boyle's, Charles', Gay Lussac's, and the combined Gas law (Be able to identify which gas law must be used & correctly use the the eq. to solve problem) ~continued~ (Ch.14)

ex. The vol. of gas-filled balloon is 30.0 L @ 313K and 153 kPa pressure. What would vol. be @ standard temp./pressure (STP)? V2=V1 x P1 x T2/P2 x T1, V2= 30.0L x 153kPa x 273 K/101.3 kPa x 313 K = 39.5 L

If given one of the following, be able to convert it into any one of the other three: [H+],[OH-],pH, pOH (Ch.19)

ex. What are the hydroxide-ion conc. for solutions w/ the following pH values? a. 4.00 pOH,pH, H+,OH- [OH-]=1 x 10^-14/ 1 x 10^-4= [H+][OH-]=1 x 10^-14 1x10^-12= pH+pOH=14 10-ph=[H+] pH=-log(1 x 10^-12)= 12

What is Enthalpy? (Be able to conduct calculations involving enthalpy)~continued~(Ch.17)

ex. When 25.0mL of water containing .025mol HCl at 25.0C is added to 25.0mL of water containing 0.025 mol NaOH at 25.0C in a foam cup caloriemeter, a reaction occurs. Calculate the enthalpy change (in kJ) during this reaction if the highest temp. is observed is 32.0C. Assume the densities of the solution are 1.00g/mL (triangle)H=-mC(triangle)T= C=4.18 J/g C; (triangle)T=32-25=7.0; m=50mL (1g/mL)=50g; -50g(4.18J/gC)(7degree)= -1500J=-1.5x10^3J=1.5kJ

What is Percent yield and Theoretical yield? Actual yield? (Be able to calculate all 3 of these values if given data from a chemical process) ~continued~(Ch.12)

ex. what is the percent yield if 13.1 g CaCO is actually produced when 24.8g CaCO3 is heated? CaCO3(s)----->CaO(s)+CO2(g) 1. 24.8g CaCO-->mol; 24.8 g x 1mol/100g=.248mol CaCO3 2. .248mol CaCO3=.248 mol CaO 3 .248 mol CaO-->g; .248 x 56 g/1 mol =13.9g CaO %yield=13.1g/13.9g= 94%

Calculating Partial Pressure (Ch.14)

ex.What is the partial pressure of oxygen (Po2) @ 101.3 kPa of total pressure if the pressures of nitrogen carbon dioxide, and other gasses are 79.10 kPa, 0.040 kPa, and 0.94 kP, respectively? Ptotal=Po2, Pco2, P N2, 32.9 kPa= 6.6 kPa + Pco2+ 23.0 kPa; 32.9 kPa=29.6kPa +Pco2; Pco2=32.0kPa-29.6 kPa= 3.3 kPa