General Questions and Answers

What type s of intermolecular forces are expected between 2 6 dimethylcyclohexanone molecules CH3 Indicate with yes or no which apply dipole forces induced dipole forces hydro CH3

Bronsted Lowry base Lewis acid Arrhenius acid Lewis base Arrhenius base Bronsted Lowry acid Proton donor Proton acceptor Produces OH in solution Electron pair acceptor Produces H3O in solution Electron pair donor

3 Rank the following acid in order of increasing acid strength the top one is the strongest There is no partial credit on this problem Strongst acid 2 1 HBrO2 HBrO3 HBrO Weakest acid

Which of the following are amphoteric Select all that apply Incorrect choices are penalized SO4 H PO4 HCO3 H O HPO4 PO43 OH CO3 HSO3 H3O

Energy kJ mol 50 37 5 25 12 5 1 2 Reaction Profile A The reaction is exothermic B The activation energy is 50 kJ mol C AH 25 0 kJ mol D Point 2 is an activated complex E The products are lower in energy than the reactants

9 Match the following points in a titration to their pH ranges Equivalence point of a weak acid strong base titration Equivalence point of a strong acid strong base titration Equivalence point of a strong acid weak base titration Halfway to the equivalence point of a weak acid strong base titration pH pKa pH 7 pH 7 pH 7 5 points Which of the following are conjugate acid base pairs Select all that apply Incorrect responses are penalized H SO and I

1 pts The vapor pressure of benzene CH is 40 1 mmHg at 7 60 C What is its vapor pressure at 87 90 C The molar heat of vaporization of benzene is 31 0 kJ mol

Identify the polyprotic acids Select all that apply Wrong answers are penalized HCIO3 HNO3 H3PO4 H CO3 HCI H SC

Give the number of valence electrons for S

Rewrite the following without an exponent 62

Which of the following correspond to standard atmospheric conditions O 0 C and 760 mmHg 25 C and 760 mm Hg O 25 C and 101 3 mmHg O 0 C and 101 3 mmHg Methane reacts with oxygen gas to produce carbon dioxide and water vapor What volume of water vapour is produced from the reaction of 4 0 L of oxygen gas 1 0 L H 0 8 0 L H O 4 O 4 0 LH 0 1 point 1 point

The Following IR spectra was obtained Interpret the Spectra and match the peaks to the functional groups in the molecule Transmitance 0 8 0 6 200 THYMOL INFRARED SPECTRUM 2005 1000

1 The actual solubility of KCI in water at 20 C is given in a solubility table as 34 0 g KC1 100 g water which is equal to a molality of 4 56 m How does your result compare to your experimental molality Is it acceptable error actual value experimental value actual value error 100 4 56 260048 4 56 2 At 50 C the solubility of KCl in water is 42 6 g in 100 g water What is the molality of KCl in water

My Activities Tell me what you want to do a Read the following extract from Federalist Paper 10 by James Madison and answer the question that follows AMONG the numerous advantages promised by a well constructed Union none deserves to be more accurately developed than its tendency to break and control the violence of faction The friend of popular governments never finds himself so much alarmed for their character and fate as when he contemplates their propensity to this dangerous vice He will not fail therefore to set a due value on any plan which without violating the principles to which he is attached provides a proper cure for it The instability injustice and confusion introduced into the public councils have in truth been the mortal diseases under which popular governments have everywhere perished as they continue to be the favorite and fruitful topics from which the adversaries to liberty derive their most specious declamations In Federalist Paper 10 James Madison uses the phrase Happy Combination What does he mean by it O Co existence of National and State Governments O Direct Democracy O Rule of factions

The following orbital diagram is incorrect but it has the correct number of electrons represented by arrows for a neutral uncharged atom Which two statements are true Increasing Energy 7s 6s 5s 3s 7p 6p 5p 4 4p 3p 2p 6d 5d 4d 3d 5f 4f

Question 4 Points 2 Read the excerpt adapted from Wikipedia and answer the question that follows The Big Bang theory is the prevailing cosmological model of the early development of the universe The major premise of the Big Bang theory is that the universe was once in an extremely hot and dense state that expanded rapidly a Big Bang This rapid expansion caused the young universe to cool and resulted in its present continuously expanding state According to recent measurements scientific evidence and observations the original state happened around 13 7 billion years ago this can be referred to as the time that the Big Bang occurred According to the passage which among the following will happen in another few billion years O The universe will expand more The universe will cool more The universe will expand and become cooler None of the choices

The reaction below has a Kp value of 41 What is the value of Kc for this reaction at 400 K N2 g 3 H g 2 NH3 g

e Using 0 9850 M NaOH in your calculations instead of the correct value of 1 300 M NaOH Hint Look up your molarity calculation to see what happens to the answer if the wrong NaOH molarity is used 3 Primary standards are very pure solids They have the advantage that they can be weighed using an analytical balance and they are stable under laboratory condi tions In an experiment the primary standard oxalic acid dihydrate H C O 2H O was used to standardize a solution of sodium hydroxide The reaction can be described by the following equation 2 pts 2NaOH aq H C O 2H O s Na C O aq 4H O 1 a Calculate the molarity of an oxalic acid solution if it takes 34 0 mL of 0 200 M NaOH solution to consume the acid in a 25 0 mL sample of this ox alic acid solution 34 0mL NaOH x 0 0034 10 3L IML x 0 200 mol NaOH IL NaOH X 1 mol H C O 2 mol NaOH b Calculate the mass of H C O 2H O required in the standardization

Classify Complete and balance each of the follo reaction equations No combination or decomposition reactions appear in this excercise because you Can t reliaby predict their products with your Current level of Chemistry knowledge 7 8 9 0 Zn s K S aq CoBrz aq C6H 2 1 12 Brz 1 AU NO3 3 aq Cd C1 aq Al S 0 9 KI aq

What did Nathaniel Hawthorne s work feature O Fragility of illusion O The institution of slavery O Moral allegories with a Puritan inspiration Development of young people s character and morality

CuSO4 aq Zn s Cu s ZnSO4 aq The single replacement reaction above produces 157 0 g of copper and an unknown amount of zinc sulfate What mass of Zn was used in the reaction Answer to the tenths place Molar mass of Cu 63 55 g mol Molar mass of Zn 65 38 g mol Answer g of zinc

Carbon dioxide can be produced by burning carbon in oxygen C O2 CO2 Approximately how many moles of carbon dioxide can be created from 24 0 g C O 24 mol 2 0 mol 12 mol 22 mol 44 mol O 0 20 mol 0 50 mol

The reaction between iron II Fe and dichromate Cr O2 in the presence of a strong acid H is shown Cr O 6 Fe 14 H 2 Cr 6 Fe 7 H O Determine the volume in milliliters of a 0 140 M solution of Mohr s salt NH4 Fe SO4 2 6H O needed to completely react with 0 0500 L of 0 140 M potassium dichromate K Cr O7 volume mL What volume in milliliters of 0 140 M K Cr O is required to completely react with 0 0500 L of a 0 140 M solution of Mohr s salt

How many moles of the excess reagent remain after 2 0 mol Al and 2 0 mol Cl react 2 Al s 3 Cl 1 2 AlCl3 s

5 Co3FeAs8

For the balanced equation below determine the approximate mass of ammonia NH3 produced from 2 3 mol of calcium hydroxide NH4 2SO4 Ca OH 2 2NH3 CaSO4 2H2O 0 068 g 39 g 78 g 0 27 g 52 g

Read the following lines from the essay On Reading and Books by Arthur Schopenhauer and answer the question that follows Esau who while hunting the deer for his father was robbed of the blessing by Jacob disguised in his brother s coat The writer has used which of the following in this statement Descriptive Narrative

H2O Which of the following questions are MOST appropriate to identify water s behavior in this reaction Will water accept a proton to form a conjugate base Will HCI donate a proton and act as a base Will HCI donate a proton and act as an acid ONGULUGU the proton Lact as a base

3 Part B 2 The burning of the magnesium becomes uncontrolled it burns brightly Oops Will the reported mole ratio of magnesium to oxygen be too high or too low as a result of this technique error Explain 4 Part B 3 In a hurry to complete the experiment Sylvia did not allow all of the magnesium to react Will her reported magnesium to oxygen ratio be reported too high or too low Explain

Something is wrong with all 4 of these hypothetical student responses orbital diagrams or electron configurations Your Why is the response wrong 1 point What is the real correct answer 1 point Using what you actually know about the content provide the real response that should have been provided There are 4 hypothetical responses so this is worth a total of 8 points 2 points each In your post refer to the responses by their numbe Here are the responses Student Response 1 2 3 Question What is the electron configuration for lithium How many electrons are in the 2p level for fluorine Which block of the periodic table is helium found in Incorrect Response 15 7 electrons The p block

25 mL of 0 1 mol L HCI is mixed with 0 4 g of an unknown carbonate Determine the molar mass from the carbon dioxide produced pressure in the room 98 kPa volume of CO2 12 5 temperature of the water 26 C

4 Classify complete and balance each of the following reaction equations No combination or decomposition reactions appear in this exercise because you can t reliably predict their products with your current level of chemistry knowledge C4H10O 1 O g 5 H SO4 aq 3 Al s Pb NO3 2 aq BaBr aq Na3AsO4 aq C5H10 1 MgCl aq O g

A student makes a diluted solution of caffeine by pipetting 8 0 mL of the stock caffeine solution into a test tube and dilutes it with 8 0 mL distilled water If the concentration of the stock caffeine is 10 m m what would be the concentration of caffeine in mg ml in the test tube

How many moles of carbon are there in 153 g of calcium oxalate CaC 04 Molar Mass of CaC2O4 128 10 g mol

1206 17 8 g 16 0 g Question 6 1 point E Listen Water can be separated into its elements according to the following equation by electrolysis If 20 0g of water is decomposed by this method how much oxygen gas is produced 10 0 g 02 35 6 g A H O 2 H O g 2 H g O g

Draw a diagram that shows what happens to the compound when it is added to water Briefly explain what is happening Show the role of water molecules in this process Remember that not all compounds are soluble in water

Rather than combining 4 00 g of Na2SO4 142 04 g mol with a solution containing 10 0 g of H SO4 98 08 g mol a student accidentally used 4 00 g of sodium sulfide 78 05 g mol with the acid The acid reacted with the sodium sulfide to produce highly toxic hydrogen sulfide gas How many moles of hydrogen sulfide 34 08 g mol were produced 0 0510 mol 0 102 mol 0 0512 mol 0 0257 mol 0 0315 mol Na S s H SO aq Na SO4 aq H S g

In a demonstration of the complete combustion of propane C3Hg with oxygen O2 several balloons were prepared with various proportions by volume of propane and oxygen The loudest explosion occurred for the balloon with the correct stoichiometric proportions of the gases Which balloon had the loudest explosion 01 portion propane to 1 portion oxygen 1 portion propane to 3 portions oxygen 1 portion propane to 4 portions oxygen 1 portion propane to 5 portions oxygen 2 portions propane to 3 portions oxygen Question 12 1 point 4 Listen Which statement about a balanced chemical reaction equation is always correct O The total number of moles of the products equals the total number of moles of the reactants The number of atoms of each kind is the same for the products as for the reactants O The sum of the stoichiometric coefficients for the products equals the sum of the stoichiometric coefficients for the reactants The sum of the masses of all gaseous products equals the sum of the masses of the gaseous reactants The sum of the masses of solid products equals the sum of

matter Question 8 1 point Listen Which should give the least vigorous reaction when dropped in water Li Na

If a sample contains 2 651 mol calcium carbonate CaCO3 what is the mass in grams of the sample

The following reaction is classified as a CH3 CO Na HClO4 CH3 CO2 H NaClO4 displacement and decomposition reaction displacement reaction combination and decomposition reaction decomposition reaction combination reaction

What is the sum of the coefficients of the following equation when it is balanced C6H12O6 O2 CO2 H O

What are the correct coefficients reading from left to right when the chemical equation is balanced 12 Cl H O HIO3 HCI 1 2 3 1 3 1 1 1 1 1 O 1 5 1 2 1 O2 1 2 1 5 1 5 6 2 10

How many moles of sulfide ions are in 8 64 mol of aluminum sulfide Al2S3 ahloride SirCle

20 0 g of silver was reacted with excess chlorine as in the following equation 2 Ag Cl 2 AgCl 20 0 g of silver chloride was collected What are the percent yield Molar mass of Ag 107 9g mol AgCI MM 143 3 g mol 52 5 13 6 73 5 78 5 64 5

Lead II nitrate and ammonium iodide react to form lead II iodide and ammonium nitrate according to the reaction Pb NO3 2 aq 2NH I aq Pbl s 2NH4NO3 aq What volume of a 0 490 M NH4I solution is required to react with 335 mL of a 0 620 M Pb NO3 2 solution volume How many moles of Pbl2 are formed from this reaction moles mL mol RhI

11 Integration 10 2 2 9 8 7 6 5 ppm 2 4 3 3 N 2 3 1 0

Balance the following equation by inserting coefficients for the reaction of aqueous Pb ClO3 with aqueous Nal equation Pb ClO3 aq Nal aq Incorrect What mass of lead iodide solid will form if 1 50 L of concentrated Pb ClO3 2 is mixed with 0 150 L of 0 160 M Nal Assume the reaction goes to completion mass of lead iodide solid Pbl s NaClO3 aq 6 22

3A 2B C 2D A B D Oc Question 6 1 point 4 Listen Balance the following reactions 12 Cl2 H O HIO3 HCI

3 a Experimental Procedure Part A List two reasons for using crucible tongs to handle the crucible and lid after their initial firing b Why is it best to cool the crucible and lid and sample in a desiccator rather than on the laboratory bench 15b