Chemistry Questions and Answers May 28, 2020

Two reactions and their equilibrium constants are given. A 2 B 2C K1 2.97 2 C D K2 0.246 Calculate the value of the equilibrium constant for the reaction D A 2 B. K ,Two reactions and their equilibrium constants are given. A 2 B 2C K1 2.97 2 C D K2 0.246 Calculate the value of the equilibrium constant for the reaction D A 2 B. K

12. Hydrocarbon mixtures are used as fuels. (State the atomic mass of each atom you are using for each solution) How many grams of CO(g) are produced by the combustion of 200. g of a mixture that is 25.0 CH, and 75.0 Catt, by mass 13. Nitrogen (N), phosphorus (P), and potassium (K) are the main nutrients in plant fertilizers. By industry

1. Which one of the following structures is not a resonance structure of the other three structures D) C) NH2 B) A) NH2 NH2 NH2

Calculate the annual inhalation dose when the ALI is 4.0 Ci. Assume the air concentration of the soluble strontium compound is 0.005 Ci/m3.

Activity 1. COMPARE ME Compare the pictures in each set. A. shutterst ck Rock rolled uphill and downhill. (Image Source hitpsiencrypted tbn0.gstatic.comimagesgtbn 3AANG9GcRJCzeHyDYohm4N7w Zmeitrausqp3CAU b00whumool 1. What can you say about the pictures 2. How do you compare the pictures 3. Which one is more spontaneous Why

Directions Write TRUE if the statement is correct but if its false, change the underlined word or group of words to make the whole statement true. 1. If heat flows into the surroundings, the random motion of the molecules in the surroundings decreases. 2. in a chemical reaction, the heat change is positive if the heat product is lower than the

1. What can you say about the pictures? 2. How do you compare the pictures? 3. Which one is more spontaneous? Why?

Shuttersteck

How does spontaneity apply to a chemical reaction?

How do entropy changes occur?

(a) An enzyme catalyzed reaction that involves two substrates gave the kinetic data in the table below at a fixed enzyme concentration of 100 nM. Use the data to determine if the enzyme follows a pingpong or sequential mechanism, and determine all associated KM and Vmax values. 25 40 mM 200 mM So v (S2o 50 M) (mol s1) v (S2o 100 uM) v (S2o 250

Mr Tembo has shares in XYZ Limited, a company not listed on LuSE. He bought 500,000 shares in 2010 for K2,000,000. He has disposed off 300,000 shares for K3,000,000. Required: Calculate the PTT assessable on Mr. Tembo. How do you explain the realisable value of Shares on disposal regarding assessibility to Property Transfer Tax.

What have you learned about the spontaneous process and entropy?

How is hot object in an open area gets cooler?

General rules in predicting entropy change of the system 1. If the reaction produces more gas molecules than it consumes, AS is positive. 2. If the total number of gas molecules diminishes, AS is negative. 3. If there is no net change in the total number of gas molecules, AS may be positive or negative, but will be relatively small numerically.

Explain briefly how second law of thermodynamics applies in the following: 1. Eating food 2. Hot cup coffe in a table

1. What is the second law of thermodynamics? 2. What does second law of thermodynamics tells about the entropy of spontaneous processes and processes at equilibrium?

Boron, with an atomic mass of 10,811 AMU, is made up of two isotopes, 10B and 11B, whose respective isotopic masses are 10.0129 am and 11.0093 am. Calculate the natural abundance of these isotopes.

CALCULATE THE CONCENTRATION (% m / v) OF A SOLUTION PREPARED BY DISSOLVING 3 g OF MAGNESIUM SULFATE IN WATER, UP TO 80 ml OF SOLUTION.

Are evaporation, condensation and boiling exclusively chemical changes? (sustains)

Solid NaBr is slowly added to a solution that is 0.054 M in Cu and 0.054 M in Ag. Which compound will begin to precipitate first AgBr CuBr What percent of Ag remains in solution at the point when CuBr just begins to precipitate ,Solid NaBr is slowly added to a solution that is 0.054 M in Cu and 0.054 M in Ag. Which compound will begin to

A certain element that does not react with oxygen has in the nuclei of its atoms more protons than sulfur and less than calcium. What is the symbol of the element, what is its mass number and to which group does it belong?

Hydrogen fluoride that is used to make freons (which destroy the stratospheric ozone layer), is prepared by the following reaction: CaF2 + H2SO4 CaSO4 + 2 HF If 200g of CaF are reacted with 500g of H2SO4. What is the limiting reagent? Show the procedures

Suppose you perform an EAS reaction using 2.47 grams of isopropyl benzene, sodium iodide (1.2 equivalents) ethanol (in excess) and bleach (in excess). After purification, a disubstituted aromatic compound was recovered. Calculate the theoretical yield of the expected product. Type answer

A gas occupies a volume of 200 mL at a pressure of 400 Torr. At what pressure must the gas be for the volume to change to 75 mL.

What volume will 2.5 L of a gas occupy if the pressure changes from 760 mm Hg to 630 Torr?

One more given of hydrogen occupies 40 L at 700 Torr. What volume will it occupy at 5 atm of pressure?

2.5 L of gas at a temperature of 30 C. If the temperature rises to 58 C. What will its volume be?

The volume of SO2 is 26 L at 27 C, if the volume was reduced to 5L What is the temperature in degrees Celcius?

150 mL of gas at 17 C. What will its volume be at 100 C?

A gas is in a cylinder at 45 C and a pressure of 650 Torr. What will the pressure be if the temperature changes at 100 C?

Hydrogen that is stored in a metal cylinder has a pressure of 252 atm at 25 C. What will the pressure be in the cylinder when it is immersed in liquid nitrogen at -196 C?

The temperature of a volume of H2 is 120 C at 3 atm of pressure. What is the temperature in C if the pressure drops to 580 mmHg?

A volume of SO is in a container at 150 C and 970 mmHg. What is the temperature in C if the pressure increased to 2.8 atm?

A tank contains methane 30 C and 5 atm of pressure. What is the internal pressure when heated to 90 C?

A gas occupies 2500 mL at 700 Torr and 22 C. When the pressure changes to 500 Torr. What temperature in C is needed to maintain the same volume?

At what temperature must 5 L of oxygen that is at 50 C and 600 Torr be heated to have a volume of 10 L and a pressure of 800 Torr?

The volume of a gas-filled balloon is 50.0 L at 20 C and 742 Torr. What volume will it occupy at normal pressure and temperature?

At what temperature must 10.0 L of nitrogen at 25 C and 700 Torr be heated to have a volume of 15.0 L and a pressure of 760 Torr?

Calculate the pH of the solution after the addition of each of the given amounts of 0.0597 M HNO, to a 70.0 mL solution of 0.0750 M aziridine. The pK, of aziridinium is 8.04. What is the pH of the solution after the addition of 0.00 mL HNO, pH What is the pH of the solution after the addition of 5.28 mL HNO, pH What is the pH of the solution

Given 20 L of ammonia gas at 5 C and 730 Torr, calculate the volume at 50 C and 800 Torr.

250 mL of gas measured at 50 C and 780 mmHg pressure, what volume will it occupy in CN?

10 L of CO2 measured at 4 C and 500 mmHg. Determine its volume at 30 C and 800 mmHg pressure?

The volume of chlorine at 20 C and 1 atm of pressure is 150 L. What volume will it occupy at 60 C and 2770 mmHg of pressure?

What volume of O2 at 20 C and 1 atm of pressure can be obtained from 100 g of KClO3?

A gas has a density of 1.05 g / L at 18 C and 640 mmHg, what is the molecular weight?

What is the density of CO2 at 40 C and 5 atm of pressure?

What is the molecular weight of a gas if 15 g occupies a volume of 4 liters at a temperature of 30 C and a pressure of 795 mmHg?

If 300 mL of gas weigh 0.85 g in CN. What is its molecular weight?

At what temperature must 3 moles of gas be heated in a 30-liter container to maintain a pressure of 178 mmHg?

Calculate the number of moles of a gas that occupies a volume of 20 liters at a temperature of 25 C and 25 atm of pressure.n

What volume will 1 mole of CO occupy in NTP?

As we observed in Lab 2, iodine binds with starch to form a deep blue-black complex: iodine + starch starch-iodine complex Place 50 mL of water into one of your beakers (tap water is fine). Add a pinch of cornstarch or a few drops of liquid laundry starch and stir to dissolve. Add 3 drops of iodine tincture and swirl. You should see the

Draw the mechanism for the three FriedelCrafts acylation reactions below AIC13 1. Cl

b. Where in nature would you find solutions with more than 1 M Na and SO dissolved in them What effect would all that salt have on most dissolution precipitation reactions ,b. Where in nature would you find solutions with more than 1 M Na and SO dissolved in them What effect would all that salt have on most dissolution precipitation reactions

Activity 2 EXAMINE ME Directions Examine the given chemical reactions and answer the given questions in each item. 1. Label the following as oxidation or reduction. a. Conversion of Br to Br2 b. Conversion of Fe2 to Fe3 c. Change in oxidation number in a negative direction. 2. In the balanced equation 12 5Cl2 6H2O 2HIO3 10HCI a. What element was

Directions Inspect very well the given chemical reactions and balance tne reaction. If the reaction is already balanced, just write the word balance beside the equation. This will serve as your review in balancing chemical reactions. NasPO4 KOH NaOH KaPO4 MGF2 LizCO3 P4 AGNO3 Cu Cu(NO3)2 Ag 5. 1. PER 2. M9CO3 LiF 3. O2 P2O3 4. CF4 GaF3 N2 8.

Directions Inspect the given reactions very carefully, follow the given step bystep procedure to balance the equation. 1. lag)Clz) H2Om HIOsaq) HCl(ac) 2. Sno HNO3(ag) SnO2(0) NO20) H2O 3. Ales) Ag(g) Al3 Ag) 4. Ka) Cr (aq) Cre) K (ea 5. Zno) Sn2(aq) Zn2(aq) Sne) 6. H(agCre) Hza) Cr (a) 7. Cue)NO3(aq) Cu2 (ac) NO2g) 8. H2Ozag) CIO2ag)

A NaH2PO4 (0.10 M) / Na2HPO4 (0.070 M) buffer is prepared. Calculate a) pH b) c) How many moles of a strong acid are required to vary the pH of 250 mL of the buffer solution by 0.5 pH units.

What is the concentration of an acetic acid solution that ionizes by 3.0%?

Calculate the pH of a 0.100 M Na3PO4 solution.

Calculate the pH and buffering capacity () of a NH4OH / NH4Cl system with an ionic strength 0.4. ([NH4OH] = [NH4Cl]).

Calculate the ionic strength and the activity coefficient of Fe2+ of a solution that is: La(NO3)3 0.030 M + Fe(NO3)2 0.060 M.

How much does a 0.100 M solution of a weak acid HA have to be diluted to triple its ionization percentage? Assume C> 100 Ka

Suggest an acid / base pair to prepare a pH 9.0 buffer. Justify your answer.

Briefly describe and give an example of: 1. leveling solvent: 2. differentiating solvent:

Under what conditions is the buffer capacity () of a buffer exhausted?

What is the effect of dilutiion in a buffer solution?

What role does the solvent play in acid-base systems?

Calculate the pH of the following solutions (<5% error): a) HF 0.01 M. b) NH4Cl 0.01 M. c) 0.01 M ammonium acetate.

Calculate the pH of the following solutions (<5% error): a) CH3COOH (0.1 M) + HClO (0.05 M) b) K2HPO4 (0.25 M)

Hydrogen fluoride that is used to make freons (which destroy the stratospheric ozone layer), is prepared by the following reaction: CaF2 + H2SO4 CaSO4, + 2 HF If 200 g of CaF are reacted with 500 g of H2SO4, how many grams of CaSO4 are produced?

Iron has a BCC crystal structure at room temperature, and a lattice constant, a, of 0.286 nm. How many atoms are contained within the (10 0) plane Answer

The bottle of a Caustic soda scale remover shows its label the information of the active ingredient NaOH 0.01 M if the bottle has a volume of 300 ML. How many grams of sodium hydroxide does the scale remover contain.

2C 8 H 18 + 25O 2 = 16CO 2 + 18H 2 O. Find additional pressure from a 1.00g mass of octane. Volume is 1L. Compare additional pressure to the initial pressure of 25 bar.

Label any peaks/structures

INFRARED SPECTRUM 0.8 0.6 0.4 0.2 2000 1000 3000 Wavenumber (cm1) Relative Transmittance 1.

A parallel-plate capacitor is charged to 5000 V. A proton is fired into the center of the capacitor at a speed of 3.710 5 m/s) . The proton is deflected while inside the capacitor, and the plates are long enough that the proton will hit one of them before emerging from the far side of the capacitor. What is the impact speed of the proton?

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A crystalline form of molybdenum has a face centered cubic structure. If the radius of a molybdenum atom is 139 pm, calculate its density. (hint): answer should be 10.3 g/cm 3

Calculate the pH of the following solutions : a) HF 0.01 M. b) NH4Cl 0.01 M. c) 0.01 M ammonium acetate.

For a solution, of HCN, in which = 8.0x10^-2 (activity coefficient), calculate the thermodynamic equilibrium constant of HCN (Ka (HCN) = 7.20E-10).

Tell what is the behavior of urea in the following media . NH,CONH, , NH,CONH, OH b. NH,CONH, HCOOH NH,CONH HCOOO NH,CONH, NH3 NH,CONH NH, . d. NH,CONH2 H,O NH,CONH H,0

a) For each of the following acid solutions, predict whether the x is small approximation is valid (write yes or no for each solution). i) 0.006 M hydrofluoric acid (K a = 6.8 x 10 -4 ) ii) 1.0 M hydrocyanic acid (K a = 4.9 x 10 -10 ) iii) 0.10 M chlorous acid (K a = 1.1 x 10 -2 ) iv) 0.30 M acetic acid (K a = 1.8 x 10 -5 ) b) Calculate the pH of

Part 1: Starch-iodine complex As we observed in Lab 2, iodine binds with starch to form a deep blue-black complex: iodine + starch starch-iodine complex Place 50 mL of water into one of your beakers (tap water is fine). Add a pinch of cornstarch or a few drops of liquid laundry starch and stir to dissolve. Add 3 drops of iodine tincture and

7) Br heat CHCO,H (solvent acetic acid)

Calculate the pH of a mixture that is 0.010 M nitric acid and 2.0 M chlorous acid Calculate the pH of a 0.30 M acetic acid solution.0.30 M acetic acid (K a = 1.8 x 10 -5 )

c) For each of the following mixtures, predict whether we can ignore the contribution of the weaker acid to the overall pH (yes or no). i) 0.010 M nitric acid + 2.0 M chlorous acid ii) 1.0 M hydrofluoric acid + 0.20 M hydrocyanic acid iii) 0.30 M hydrofluoric acid + 0.40 M acetic acid iv) 1.0 M chlorous acid + 1.0 M hydrocyanic acid

An equilibrium mixture contains 0.400 mol of each of the products (carbon dioxide and hydrogen gas) and 0.200 mol of each of the reactants (carbon monoxide and water vapor) in a 1.00 L container. CO(g) H,O(g) CO,(g) H, (g) How many moles of carbon dioxide would have to be added at constant temperature and volume to increase the amount of carbon

What is the H3O of a pH 8.39 (watch your sig figs)

d) Calculate the pH of a mixture that is 0.010 M nitric acid and 2.0 M chlorous acid.

Calculate pcu when 0.040 00 M CUNO3 is used to titrate 34.0 ml of 0.500 0 M KC at the equivalence point. Ksp Cuci 1.9 x 107. Answer using QUESTION 13 Calculate pAg when 19.00 ml of 0.200 M Nalog is titrated with 61.00 mL of 0.100 M AgNO3. Ksp 3.1 x 108 for Ag 103. QUESTION 14 Using activity coefficients. calculate the pH of a solution with

The IN of an unknown oil is 58, what is its BN? (MW Br2= 80 g/mol, MW I2=126 g/mol)

An unknown compound has the molecular formula of CaH,CIO with MS spectrum below. DETERMINE the possible molecular structure and validate it with MS cleavage pathways. 100 80 60 40 20 75 100 125 150 25 50 mz ,An unknown compound has the molecular formula of CaH,CIO with MS spectrum below. DETERMINE the possible molecular structure and validate it

3. Some projection models put the carbon dioxide concentration at 1255 ppm by the year 2100. Calculate (CO2 in rainwater at this concentration. KH.034 mol(L Atm). Calculate the pH of the rainwater if all the CO2 reacts with water to produce carbonic acid (H,CO3, pka 3.6) (ignore the partial pressure of water).

For the titration of an aqueous ammonia solution, NH3lag), with an aqueous hydrobromic acid solution, HBrlaa), which of the following chemical species will be present in highest concentration at the equivalence point O NHlag) O OH (ag) O NH,(ag) O All of these chemical species will be present in highest concentration at the equivalence point. O

For the titration of an aqueous nitrous acid solution, HNO,(aq), with an aqueous strontium hydroxide solution, Sr(OH)2aq), what do you expect the pH of the solution to be at the equivalence point O Basic (pH 7.00) O Unable to determine the pH of the solution at the equivalence point without additional information O Acidic (pH 7.00) O Neutral (pH

1. How many grams of sucrose in present in 2L of water of a 25% solution? 2. How many grams of sucrose is present in 520 ml. of water of a 30% solution? 3. How many grams of sucrose is present in 250 mi. of water of a 20% solution? 4. Shannon made a 20-X solution using the original recipe as a reference for the components she added. 5. We need to

Referring to the AlISi Eutectic diagram discussed on the Phase DiagramsLever Rule handout, calculate the mass fraction of the B phase, silicon, given a sample with 6.3 wt alumimum at 576.99 C.

A 8.55 g sample of aniline (C6H5NH2, molar mass 93.13 gmol) was combusted in a bomb calorimeter. If the temperature rose by 33.9C, use the information below to determine the heat capacity of the calorimeter. 3D 4 CgHsNH2(1) 35 O2(g) 24 CO2(g) 14 H20(g) 4 NO2(g) AHrxn 1.28 x 104 kJ 97.3 kJC 38.9 kJC 5.94 kJ C 6.84 kJC 8.67 kJC

Write down the Molecular formula of the following 1. p-Chlorophenol 2. p-Diisopropylbenzene 3. 2,4,6-Tribromoaniline 4. m-Nitroacetophenone 5. 4-Bromo-3-ethyl styrene

4. What carbonyl compounds give the following alcohols on reduction with LIAIH4 Show all possibilities. (a) CH2OH (b) (c) OH CHCH3