Energetics Questions and Answers

When looking back at the directions you realized that you skipped a step and had to redo the trial After getting the new data you found that the amount of energy lost to the calorimeter was 660 J the warm water was at 43 2 C right before it was added to the calorimeter containing cooler water at 17 5 C After stirring and waiting for the system to equilibrate the final temperature reached 34 4 C Calculate the heat capacity of this cllorimeter Report your answer to three significant figures

The reaction for which 4 H 4 Hco is CH g 20 g CO g 2H O CO g 10 g CO g C graphite O g CO g C diamond O g CO g

10 moles of gas compressed reversible from 10 L to 1 L at constant temperature The entropy change during the process is 10 R 10 R 23 03 R

For the reaction 3N O g 2NH3 g 4N g 3H O g If AH NH3 g 45 9 kJ mol AH H O g 241 8 kJ mol then AH N O g will be a 246 kJ c 82 kJ b 82 kJ d 246 kJ AH 879 6 kJ

The standard lattice enthalpy of NaCl is AsubH Na 108 4 A H Na 496 AbondH Cl 242 AegH CI 348 6 and AfH NaCl 411 2 All data is in kJ mol O 514 kJ mol 1 O 642 kJ mol 1 O 788 kJ mol 1 00 LI 1

Choose the correct answer A thermodynamic state function is a quantity i used to determine heat changes ii whose value is independent of path iii used to determine pressure volume work iv whose value depends on temperature only

Calculate the total work in Joule of the cycle process in Figure below if you know that the PA 3 78 P 1 81 and Pc 0 93 Bar and VA 0 53 and VB 3 91 L Just write a number in the box without unit please P bar D V L B C

5 A sample of a gas in a cylindrical chamber with a movable piston occupied a volume of 5 50 iters when the pressure was 5 85 x 10 Pa and the temperature was 24 9 C The volume of the system was readjusted to 13 6 liters by moving the piston What was the pressure exerted on the surface of the piston by the gas if the temperature of the system remained constant a 7 22 Pa b 2 66 x 10 Pa c 2 26 x 10 Pa d 1 34 x 105 Pa e 3 90 x 105 Pa What

Using the given thermodynamic data all data in kcal mol AH CaO s 152 AH CaC s 14 AH CO g 26 How much heat is required for the formation of 32 kg of CaC2 using CaO s and C s in kcal 56 112 56000

6 20 When 2g of benzene are burnt in a bomb calorimeter the heat produced is 83 6 kJ at 298 K Calculate the enthalpy of combustion of benzene Ans 3264 1 kJ mol 6 21 The enthalpy change AH of the reaction at 298 K C H5OH 302 g 2CO g 3H O l reaction 3 is found to be 326 7 K cal Calculate AE for the given Ans AE 326 1 kcal 6 22 400 cm of a gas are compressed to half of its volume by applying a pressure of 0 5 atm During the process 6 5 J of heat flows out to the surroundings Calculate AE of the system Ans 3 63 J 6 23 Calculate the work done w and internal energy change AE when one mole of water at 100 C vaporises against an atmospheric pressure of 1 atm assuming ideal gas behaviour Heat of vaporisation of water at 100 C is 1020 cal mol Ans 740 9 cal 279 1 call 6 24 Calculate the work done in calories when 5 moles of an ideal gas are compressed isothermally and reversibly from a pressure of 1 5 atm to 15 atm at

A chemist heats 31 65 g of nickel to 80 12 C then places the metal sample in the cup of water shown in the interactive Calculate the final temperature of the water The specific heat of nickel is 0 444 J g C and the specific heat of water is 4 184 J g C

Which of the following is correct 1 Internal energy is state function 2 Internal energy is extensive property 3 Heat at constant volume is called as change in internal energy 4 All of the above A 1 1 2 33 fatdot for and k

One mole of a monoatomic perfect gas is allowed to expand adiabatically and reversibly from a pressure of 15 bar and 298 15 K to 5 bar What is the final temperature and how much work is done by the noble gas

The thermal dissociation equilibrium of CaCO s studied under different conditions CaCO s Ca0 s CO g for this equilibrium the incorrect statement is 1 AH is dependent of T 3 K is dependent on the pressure of CO at a given T 101 Ca 2 K is independent of the initial amount of CaCO 4 AH is independent of the catalyst if any

2 The internal energy of an ideal gas follows the equation U 3 5 PV k where k is a constant The gas expands from an initial volume of 0 25 m to a final volume of 0 86 m If the initial pressure is 5 N m the change in internal energy in Joules is given P 3 constant

240 Given that Bond energies of H and N are 400 KJ mol and 240 KJ mol respectively of NH is 120 KJ mol Calculate the and AH bond energy of N H bond 1 300 KJ mol 3 410 KJ mol 1 11 The foll 2 250 KJ mol 1 4 280 KJ mol LA

in a constant pressure calorimeter 224 ml of 0 1M KOH aq solution is reacted with 50 ml of 0 IMH SO aq solution then increase in temperature of solution will be assume heat capacity of calorimeter is negligible Given Specific heat of solution 1 cal gm K Density of solution 1 gm ml B IK 05 YOK DAK

If for a certain reaction AH is 30 kJ mol at 450 H the value of AS in JK 1 mol for which the sam reaction will be spontaneous at the sam temperature is NEET 2020 Phase 2 1 70 2 70 3 33 4 33 mundillupe mer13 5

An ideal mono atomic gas is confined in a cylinder with the help of a piston that can slide inside the cylinder without friction The cylinder I placed on a horizontal platform in a vacuum chamber The walls of the cylinder and the piston are made of heat insulating materials Initially the temperature of the gas is To and the piston stays in equilibrium The temperature of the gas is quickly increased n times and then the gas is allowed to expand If the piston rises and again acquires an equilibrium state find the temperature of the gas in this new equilibrium state

g 2003 57 Enthalpy 57 of CH4 Enthalpy of CH4 O CH OH is negative If 2 2 enthalpy of combustion of CH and CH OH are x and y respectively Then which relation is correct 2001 a x y b x y c x y d x y

363 7 kCal mol e for the reaction 2 337 2 kCal 4 579 5 kCal 143 Heat of neutralisation of a strong dibasic acid in dilute solution by NaOH is nearly 1 27 4 kCal eq 3 13 7 kCal eq 2 13 7 kCal eq 4 13 7 kCal mol The temperature of a 5 ml of strong acid incre

12 A 0 500 L sample of H SO solution was analyzed by taking a 100 0 mL aliquot and adding 50 0 mL of 0 342 M NaOH After the reaction occurred an excess of OH ions remained in the solution The excess base required 14 03 mL of 0 082 M HCl for neutralization Calculate the molarity of the original sample of H SO4 Sulfuric acid has two acidic hydrogens A 4 7x10 B 8 0x10 C 4 7x10 D 8 0x102 E 8 0x10

50 If AH of ICl Cl and is 17 57 121 34 and g 106 96 J mol respectively Then bond dissociation energy of ICl bond is 1 35 15 J mol 3 210 73 J mol 2 106 69 J mol 4 420 9 J mol

A reversible reaction that occurs in a single step has AH 36 0 kJ mol and E 37 2 kJ mol What is the activation energy of th reverse reaction kJ mol

How does a catalyst increase the rate of a chemical reaction Select all that apply It provides a reaction path having a larger activation energy It changes the mechanism of the reaction It makes the heat of reaction more negative O It provides a reaction path having a smaller activation energy It makes the heat of reaction more positive

How is the kinetic energy of the particles that make up a substance different after it changes state

Calculate the lattice formation enthalpy lattice energy of TICI s in kJ mol using the following thermodynamic data Heat of sublimation for TI lonization energy for TI CI CI bond energy Electron affinity for Cl Heat of formation for TICI 161 kJ mol 569 kJ mol 223 kJ mol 369 kJ mol 224 kJ mol

A 80 00 g gold plate is removed from boiling water 1 00x102 C and is immediately immersed in a calorimeter containing 61 0 g of water that is initially at 25 13 C The final temperature is 28 01 C Calculate the specific heat capacity of gold

Bonus worth up to 1 2 pt Must show work explain fully for full bonus credit Consider the following reaction and thermodynamic data CO g 2 NH3 g CH4 g H O g N g Compound CO g CH g H O g NH g AH kJ mol 110 53 74 81 241 82 46 11 Calculate AH then determine the direction in which the reaction will shift in response to a decrease in tempera

Which of the following substances would you expect to have the smallest change in temperature if the same amount of energy is applied to each substance Gold c 0 129 J g C Lead c 0 130 J g C Iron c 0 450 J g C O Wool c 1 700 J g C

Which of the following processes requires more heat energy raising the temperature of 100 g of water by 10 0 C b raising the temperature of 50 g of water by 10 0 C

For the complete combustion of C7H16 complete the equation with the name of the other substances Balance the equation before answering so you know where to place each product C7H16 11 Select 7 Select 8 Select

Once the lien has been resolved what fine will the claimant face if he or she remove the lien within 10 days of the notice of satisfaction a 100 per month b 100 per week c 10 per day d 10 per week

A chemist measures the enthalpy change AH during the following reaction C6H12O6 s 2 CO g 2 C H OH 1 Use this information to complete the table below Round each of your answers to the nearest kJ m reaction 2CO g 2C H OH 1 CH O6 s 2C6H 2O6 s 4CO g 4C H OH 1 C H 2O6 s CO g C H OH 1 AH 69 kJ AH kJ kJ S

At what temperature does this substance vaporize according to the heating curve below Temperature C 250 200 150 100 50 0 50 100 150 0 C 200 C 100 C 100 C 50 C Heating Curve A B Heating C D E

15 If a claimant places a lien for more than what is owed the claimant is guilty of under Utah law a a Class B misdemeanor b no wrongdoing c a breach of contract O d a felony

Y Part A Amax lew link to access the section in your e Text Ultraviolet radiation and radiation of shorter wavelengths can damage biological molecules because they carry enough energy to break bonds within the molecules A carbon carbon bond requires 348 kJ mol to break What i longest wavelength of radiation with enough energy to break carbon carbon bonds Express your answer using three significant figures View Available Hint s VAE O Constants Periodic B

Calculate the energy required to heat 628 0 g of iron from 1 6 C to 12 2 C Assume the specific heat capacity of iron under these conditions is 1 1 449 J g K Round your answer to 3 significant digits 1 0 0 0 00

8 The value of the owner s title policy is based on the policy is based on the a sale price of the property loan amount b loan amount loan amount c sale price of the property sale price of the property d loan amount sale price of the property while the buyer s title

8 Which law protects an owner if the general contractor fails to pay his subcontractors O a Construction registry O b Residence Lien Restriction and Lien Recovery Fund Act c Mechanic s Lien Statutes O d Agency Law

Mass of Mg that used is 0 2378 g delta T 10 4C Hcl 100 0ml 6 Use your AHren from 2 to calculate how many kg of Mg are needed to react with excess HCI to produce 5 7 megajoules of heat

View Available Hint s Submit Part B name of the compound NI3 Spell out the full name of the compound View Available Hint s Submit Part C

Set E Phase Change Diagrams The diagram below shows the heating of a substance starting with the substance below its melting point KE Temperature C Temperature C 200 180 140 120 100 80 100 90 80 40 70 60 50 40 39 What is the boiling point of the substance 80 C 40 At what temperature are solid and liquid exist at 41 At which segment or segments is the substance average kinetic energy increasing AB CD EF 42 At which segment or segments is the substance exists in two phases BC DE 43 Potential energy of the substance remains constant during which segment or segments ABCDEF 44 What is the total length of the time that the substance exists only as a liquid 12 9 is 3 min 45 What is the total length of time that the substance undergoes melting 9 3 6min 48 Is the diagram a heating curve for water or for a different substance Explain your answer No because the melting point boiling point are not same The diagram below shows the cooling of a substance starting with the substance at a temperature above its boiling point The substance is losing heat at a rate of 155 Joules per minute Melting BS1 PE Boiling 179 PE KE S 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 Time minutes B 0 2 4 6 8 10 12 14 16 E D 49 What is boiling point of the substance 50 What is the freezing point of the substance 51 What is the melting point of the substance 18 20 22 24 26 28 30 32 34 36 38 40 42 44 Time minutes 52 Which segment or segments represents a time when the substance is going through a phase change 53 Which segment or segments represents a time when the substance is in one phase 54 What is the phase or phases of the substance during segment C 55 What is the total length of time it took for the substance to change from liquid to solid 56 Describe the change in kinetic energy of the substance during segment A 57 How much heat is lost by the substance to completely change from gas to liquid 58 How much heat is lost by the substance to completely change from liquid to solid

What amount of heat in kJ is required to convert 1 00 g of water at 67 0 C to 1 00 g of steam at 100 0 C specific heat capacity of water 4 184 J g C AHvap 40 7 kJ mol

d 10 4 cm 9 9 cm 19 3 cm Calculator answer

The standard enthalpies of formation at 25 00 C of methanol CH4O 1 water H O 1 and carbon dioxide CO g are respectively 238 7 kJ mol 285 8 kJ mol and 393 5 kJ mol Calculate the change in the entropy of the surroundings in J K upon the combustion of 14 8 g of methanol under a constant pressure of 1 000 atm and a temperature of 25 00 C N B combustion is the reaction of this substance with molecular oxygen to produce water and carbon dioxide

a The reaction of NO g and CO g is thought to occur in two steps Step 1 Slow NO g NO2 g NO g NO3 g Step 2 Fast NO3 g CO g NO g CO g Add the elementary steps to give the overall stoichiometric reaction Use the lowest possible coefficients Be sure to specify states such as aq or s If a box is not needed leave

The solubility of pure oxygen in water at 20 0 C and 760 torr is 4 30 103 g O per liter H O When air is in contact with water and the air pressure is 655 torr at 20 0 C how many grams of oxygen from the air dissolves in 1 00 L of water The average concentration of oxygen in the air is 21 1 v v

Given the following balanced equation determine the rate of reaction with respect to 0 If the rate of O loss is 2 64 x 10 3 M s what is the rate of formation of SO3 2 SO2 g O2 g 2 SO3 g 1 32 x 103 M s 1 19 x 103 M s 5 28 x 103 M s 6 60 x 102 M s O 2 64 103 M s

What is Absolute Zero and what is its temperature in C and K What is entropy