General organic chemistry Questions and Answers

3 Discuss the isomerism shown by Co NH3 4Br2C1

The ability of a solution to resist changes to the pH from added acid or base depends upon the amount of weak acid and weak base The buffering capacity is the ratio of weak acid to weak base and the best buffering occurs when these are equal making the buffering capacity equal to 1 In the above buffer the buffering capacity is the ratio of H PO4 1 to HPO4 or K H PO4 H 0 K 4 44 x 105 K 8 HPO42 5 55 x 10 5 10 Here the buffering capacity is close to 1 0 8 and so the buffering capacity is When the buffering capacity is 1 the H 0 K and the pH pKa This helps chemists choose the right buffer for the needed pH To buffer at pH 7 the weak acid should a pK of close to 7 True or False the weak acid should have K of close to 1 x 107 True or False A good B bad C true D false W

Which of the following statements is not true A nonspontaneous process cannot be made spontaneous A spontaneous process always moves towards equilibrium a highly spontaneous process need not occur rapidly The reverse of a spontaneous reaction is always nonspontaneous

Consider the reaction 2A 25 kcal mol 2B C and its energy diagram 60 50 40 kcal mol 30 20 10 0 True or false questions course of rx the AE is a constant for the reaction the AE determines the Keq the rate is determined by the amount of energy in the transition state designated the activation energy is another name for the energy in the transition state

Provide the correct IUPAC name for the compound shown here O 5 4 2 1 6 3 X

Provide the correct IUPAC name for the compound shown here I

Provide the correct IUPAC name for the compound shown here H3C SH CH3

Which substance has the highest entropy at 25 C MgCO3 s O C H4 g CH3OH 1 O Clawanbitol

Buffers are solutions that buffer against large changes in pH when an acid or base is added Buffers contain a weak acid to neutralize added base and a weak base to neutralize added acid Most buffer problems want you to calculate the pH For example Calculate the pH of a buffer made from dihydrogen phosphate and hydrogen phosphate when the H PO4 4 44 x 105 M the HPO4 5 55 x 105 M and the K 6 20 x 108 i First identify the acid It s either H PO4 or HPO42 The acid is ii Then write the reaction for the acid dissolving in water iii Then write the expression for the Ka HPO42 H 0 Ka iv Then solve for H 0 and input the number Kal H 0 H O O HPO42 H 0 HPO42 v Finally calculate the pH 6 20 x 10 8X 5 55 x 105 because it has the most acidic hydrogens

For each of the following reactions indicate whether you would expect the entropy of the system to increase 1 AS 0 decrease D AS 0 If you cannot tell by inspecting the equation mark NA a CH OH 1 CH OH g b N O4 g 2 NO g c CO g H O g CO g H g d 2 KCIO3 s 2 KCl s 3 O 8 e HC H O2 1 HC H O s F N2 g O2 g 2 NO g ON H4 1 N g 2 H g 2 NH3 g H SO4 aq NH4 2SO4 aq

13 38 Propose a plausible mechanism for each of the following transformations a x b c f d f 1 EtMgBr 2 H O OH 1 H CEC 2 H O H SO 1 NaH 2 Etl X OH Na HO OH OEt

What is the pH of a solution prepared by mixing 500 mL of 0 10 M NaOCI and 500 mL of 0 17 M HOCI Please report 2 decimal places K HOCI 3 2 x 10 8

A mixture of methane and argon gases is maintained in a 9 25 L flask at a pressure of 1 71 atm and a temperature of 30 C If the gas mixture contains 7 23 grams of methane the number of grams of argon in the mixture is g Submit Answer Retry Entire Group 9 more group attempts remaining

Consider the reaction FeO s Fets O Fe O s Given the table of thermodynamic values Substance 1235 FeO s Fe O3 s O618 1 Fe s 0756 3 0 8 AH a 271 9 O 0 822 16 5 4x 60 75 27 15 Determine the temperature in C above which the reaction is spontaneous 205 0 89 96 This reaction is spontaneous at all temperatures

Question 25 Zinc metal will react with nitric acid vigoursly hint for acid formula ic ate What mass of zinc metal will react completely with 40 0 mL of 0 200M Nitric Acid need balanced equation O 0 26 g 0 98 g 3 1 g 1 2 g

Determine oxidation s for the following b CO3 C Fe Brz d CuI a NH CI Balancing redox equations using the half rxns in acidic soln use the steps Cr 1 2 Cr O I

Use your calculator for the following 1 When H3O 5 555 x 104 the pH this is an solution 2 When OH 5 555 x 104 the pOH this is an solution 3 When OH 5 555 x 104 what is the pH 10 14 using H30 OH 10 14 H O pH log this is an A acidic B basic or alkaline OH solution C neutral 10 14 5 555 x 104 D 1 800 x 10 11 E 10 745

4 How many mEq are in 4L of 0 75M CaCl2 5 How many ml of 4M NaOH would it take to neutralize 120ml of 1M HCI

For the following reaction at equilibrium HCIO H O ClO H O HCIO is the H O is the clo is the H 0 is the 3 It is on the list of strong acids and so is a It is both a very It does not contain hydroxide so is a It is a The K approaches positive infinity a acid b base c conjugate acid e strong f moderately strong or weak d conjugate base 8 weak acid and a very acid base acid because it is on the list of strong acids base

How many grams of solute are present in 985 mL of 0 380 M KBr

ences to access important values if needed for this question The formal charge is the charge an element would have in a molecule or ion if all of the bonding electrons were shared equally between atoms We can draw three inequivalent Lewis structures for carbon dioxide CO The concepts of formal charge and electronegativity can help us choose the structure that is the mc significant representation 1 Assign formal charges to the elements in each of the structures below Formal Charge 01 C 02 0 C 0 A 0 C 0 0 C 0 B C 000 2 The structure that contributes most significantly to the overall electronic structure of CO2 is V

Ice the following equations OUH FeO C Fe CO C 602 01 b AI H SO4 Al SO4 3 H C SO CS COA 1

he above redox reaction use oxidation numbers to identify the element oxidized the element reduced the oxidizing agent and the reducing agent name of the element oxidized SiO32 2CI H 0Si 2CIO 2OH formula of the oxidizing agent name of the element reduced formula of the reducing agent

When all concentrations at equilibrium are known a numerical value for the constant can be calculated Give the value for the Keq given the following concentrations HF 0 030 M H3O 0 020 M F 0 020 M HF H O F H 01 F H 0 Keq A HE Hel HF B H O C F1 I D H 0 E 0 020 M F 0 030 M G 0 013 4

the above redox reaction use oxidation numbers to identify the element oxidized the element reduced the oxidizing agent and the reducing agent name of the element oxidized Cu OH 2 21 I2 Cu 20H formula of the oxidizing agent name of the element reduced formula of the reducing agent

Identify the species oxidized the species reduced the oxidizing agent and the reducing agent in the following electron transfer reaction Cl Ni 2CI Ni2 species oxidized As the reaction proceeds electrons are transferred from to oxidizing agent species reduced reducing agent

For the following reaction 4 48 grams of nitrogen gas are allowed to react with 5 77 grams of hydrogen gas nitrogen g hydrogen g ammonia g What is the maximum amount of ammonia that can be formed What is the FORMULA for the limiting reagent What amount of the grams

1 How many ATOMS of nitrogen are present in 1 49 moles of nitrogen monoxide atoms of nitrogen 2 How many MOLES of oxygen are present in 4 81x1022 molecules of nitrogen monoxide moles of oxygen

How many moles of NaOH are present in 12 5 mL of 0 110 M NaOH moles

The formal charge is the charge an element would have in a molecule or ion if all of the bonding electrons were shared equally between atoms We can draw three inequivalent Lewis structures for the bromate ion BrO3 The concepts of formal charge and electronegativity can help us choose the structure that is the best representation 1 Assign formal charges to the elements in each of the structures below Note Count oxygen atoms starting from the left for each structure Formal Charge Br 01 02 03 0 Br 0 A Br 0 0 0 B 0000 2 The best Lewis structure for BrO3 is Br 0 0 C needed for this question 0 0000 Previous

Bond Bond Energy kJ mol C 0 CI CI C CI C O 1072 242 339 732 Using the values of bond energy from the table above estimate the enthalpy change for the following reaction CO g Cl g COCI g kJ

NTERACTIVE EXAMPLE Specific Heat Capacity Calculations Using A 2 5 g sample of a metal requires 10 8 of energy to change its temperature from 23 C to 41 C Using the given information and table below determine t identity of the metal Substance Specific Heat Capacity J g C aluminum s 0 89 nickel s 0 50 iron s 0 45 0 38 0 24 0 13 copper s silver s gold s HOW DO WE GET THERE Determine the specific heat capacity of the metal Specific heat capacity s J g C

20 Which process is most likely nonspontaneous at 25 C and 1 atm A A rock climber repels down a cliff X VB C6H6 1 C6H aq C COz s CO g D A drop of water evaporates on a dry summer day y

A local AM radio station broadcasts at an energy of 5 86 10 31 kJ photon Calculate the frequency at which it is broadcasting KHz Frequency 71 VUS 103 1

Attempt in Progress a plausible mechanism for the following transformation 1 34a Low HBr x

Write the mechanism for the reaction of a SECONDARY AMINE with an ACID CHLORIDE to generate an AMIDE and H C Include the structure and names of your choices and name the product formed

Please help me understand the mechanism of this reaction of an amino group with acidic conditions and Dean Stark I will give thumbs up thank you so much in advance for your help n 8 points H N H Dean Stark a

1 09 mol sample of argon gas at a temperature of 12 0 C is found to occupy a volume of 23 2 liters The pressure of this gas sample is Submit Answer Use the References to access important values if needed for this question Retry Entire Group 9 more group attempts remaining m

ant values if needed for this question In the laboratory a student finds that it takes 202 Joules to increase the temperature of 13 0 grams of gaseous neon from 20 5 to 36 6 degrees Celsius The specific heat of neon calculated from her data is J g C

If a balloon containing 3 0 L at 25 C is cooled to 54 C what is its new volume The pressure and the moles of gas remain constant L

Ba CH CO by measuring out 106 jumol of barium acetate into a 200 mL volumetric flask and filling the A chemist prepares a solution of barium acetate flask to the mark with water Calculate the concentration in mmol L of the chemist s barium acetate solution Round your answer to 3 significant digits

The following information is given for mercury at 1 atm Tb 357 00 C Tm 39 00 C Specific heat solid 0 1410 J g C Specific heat liquid 0 1390 J g C Use the References to access important values if needed for this question AHvap 357 00 C 295 6 J g AHfus 39 00 C 11 60 J g A 29 70 g sample of solid mercury is initially at 61 00 C If 600 0 J of heat are added to the sample at constant pressure P 1 atm which of the following is Select all that apply The sample is a solid O The sample is a liquid The sample is at a temperature of 39 00 C The sample is a solid in equilibrium with liquid

12 38 Propose a mechanism for the following reaction Br OH Nah

eed explanations to why thats the answe lease 25 I and II are OCH3 Br X H HOH H 1 A enantiomers CHCH B diastereomers not isomeric OCH3 Br CH3 OH D identical E constitutional isomers

A mixture of nitrogen and argon gases at a total pressure of 705 mm Hg contains 2 23 grams of nitrogen and 6 62 grams of argon What is the partial pressure of each gas in the mixture PN PAr 11 11 mm Hg mm Hg

28 Which compound would show optical activity More than one of these B trans 1 4 Dimethylcycloheptane C cis 1 4 Dimethylcyclohexane D cis 1 4 Dimethylcycloheptane FY trans 1 4 Dimethylcyclohexane

12 44 Identify the reagents you would use to accomplish each of the following transformations OH b Idi OH OH 0 CH SERE

12 54 Propose an efficient synthesis for each of the followin transformations m C C 4 T

Predict the major product of the following reaction Y 08 OC OM A ON SOCI C D Ph

writing a chemical equation from a description of the reaction Gaseous water and solid magnesium oxide are formed by the decomposition of solid magnesium hydroxide Write a balanced chemical equation for this reaction 0 4 X