Practical Detection Questions and Answers

What is the mass of 2 5 L of chloroform in grams Chloroform has a density of 1 480 g mL

The density of butter is 0 86g mL what volume in L is occupied by 427g of butter

15 51 Compare the structures of ethylene acetylene and benzene Each of these compounds produces only one signal in its H NMR spec trum Arrange these signals in order of increasing chemical shift H H H H H H

What is the boiling point C of water on the top of Mount Everest where the atmospheric pressure is 255 0 torr AHvapH O 40 6 kJ mol normal boiling point H O 100 0 C Report your answer to 1 decimal place Your Answer

A student found a 10 630 g mixture of salt sand and iron to contain 4 813 g of iron and 3 507 g of sand Calculate the mass percentages of iron sand and salt in the mixture

Phosphoric acid H PO4 is used in detergents fertilizers toothpastes and flavoring in carbonated beverages Calculate the percent Composition of H3PO4 Ensure all work is shown

N 20 0 410 300 ON 2001 O N ethanol NN NO10100H NN 2000 Whenumbers cm 1102 NAM verwoben jon 1 1065 O O stretches This is ethanol Ethanol only has an alcohol functional group not a carboxyl group Therefore you would see the O H band at around 3300 cm 1 but very few other significant peaks m 48000 This is an example of an IR spectrum of a ketone This particular example is 2 butanone You can tell that this is not a carboxylic acid because it does not have the O H stretch at 3300 cm 1 It does however have the C O stretch at approximately 1700 cm 1 This is

Transmittance 90 80 70 60 50 40 30 20 10 0 4000 2971 hexanoic acid HHHHHO IIIIIH H C C C C C C 0 H IIIII HHHHH O H stretch and C H stretch 2000 Wavenumbers cm 1 1296 1419 C O O H stretch bend 1721 C O stretch An example of an IR for an alcohol molecule is shown below 948 O H bend D Solution and explanation This is the IR spectrum of hexanoic acid Although just from the IR this will be almost impossible to tell if you were told that the formula for this molecule was C6H1202 you could tell that this was a carboxylic acid through the infrared spectroscopy and conclude the structure of the molecule

Based on the following equation if we want to produce 25 g NaCl how many gram of MgCl would we need MgCl 2NaOH MgOH 2NaC Select the correct answer below O 13 g MgCl O20 g MgCl 26 g MgCl 50 g MgCl

1 Use the graph of solubility curves below to answer the following questions Solubility of sodium chloride sucrose and potassium chloride Grams of solute dissolved in 100 ml water 500 E 450 400 350 300 250 200 150 100 50 Sucrose 0 KNO3 NaCl 20 40 60 80 100 Temperature C a Identify the most soluble substance at 10 C 1 mark If you re not part of the solution you re part of the precipitate you b What type of solution would you have if you dissolved 98 g of KNO3 in 100 g of water at 60 C 1 mark c A student would like to make some rock candy by dissolving 290 g of sucrose into a hot cup of water at a temperature of 70 C and then allowing it to cool to 20 C How much rock candy could the student make Show your work 2 marks

Read the passage from The Royal House of Thebes In the course of their desolate wanderings Oedipus and Antigone came to Colonus a lovely spot near Athens where the one time Erinyes the Furies now the Benignant Goddesses had a place sacred to them and therefore a refuge for suppliants The blind old man and his daughter felt safe there and there Oedipus died Most unhappy in much of his life he was happy at the end The oracle which once had spoken terrible words to him comforted him when he was dying Apollo promised that he the disgraced the homeless wanderer would bring to the place where his grave should be a mysterious blessing from the gods Theseus the King of Athens received him with all honor and the old man died rejoicing that he was no longer hateful to men but welcomed as a benefactor to the land that harbored him Which statement accurately analyzes this passage from a historical perspective O People who heard this story when it was first told may have believed that oracles could predict the future accurately The characters in this story live in a society where everyone is equal The characters in this story are kind to one another even when being kind turns out to be risky or frightening People who heard this story when it was first told did not believe in sacred spaces B

For the equation shown below use Le Chatelier s principle to identify if the changes indicated will cause the reaction to A shift left B shift right C have no change or D no way to predict a change N2 g 3H2 g 2NH3 g AH 13 adding heat 14 adding hydrogen H2 15 increasing the pressure 16 removing nitrogen N2 A shift left O O B shift right O O O C have no change O D no way to predict a change

In an exothermic reaction the energy stored in the chemical bonds of the reactants is ge equal to the energy stored in the bonds of the products greater than the energy stored in the bonds of the products less than the energy stored in the bonds of the products less than the heat released

A person mixes 1mol of magnesium metal with 1 5mol of hydrochloric acid HCI The reaction below occurs What is the limiting reactant for th reaction Mg s 2HCl aq MgCl2 aq H2 g Hydrochloric Acid HCI Magnesium Chloride Magnesium Hydrogen Gas There is no limiting reactant here

Which chemical equation best represents the particle model below Is O 3P s 402 g P O5 s O 2P205 s 4P s 502 g O2P s 202 g P O5 s O4P s 502 g 2P205 s OP s O2 g P2O5 s

A sample of nitrogen N has a volume of 50 0 L at a pressure of 2 ATM What is the volume of gas at a pressure of 15 atm if there is no change in temperature 1 5 points Edit View Insert Format Tools Table

using the following TLC to answer the next question Consider the following silica gel TLC plate of compounds A B and C developed in 30 70 Ethyl acetate petroleum ether ruler plate not drawn to scale 1 07cm 0 99cm 0 75cm 0 36cm 0 25cm 0 17cm 0 0cm A 0 25cm C is at 0 36cm B C 107cm 0 99cm 0 75cm ruler plate not drawn to scale 0 36cm 0 25cm 0 17cm 10 0cm A is at 0 75cm B is at Determine the Rf values of compounds A B and C run on a silica gel TLC plate shown above This question is auto graded Round answers to the nearest hundredth For example rounding 0 843 to the nearest hundredth would give 0 84

For the cell shown the standard reduction potentials are 0 80 V for Ag and 0 76 V for Zn2 Based on the reduction potentials the electrode is where the reduction will occur and it is called the Ag 1M Ag Zn cathode Ag anode Ag cathode Zn anode voltmeter 7 wire salt bridge 1M Zn2 Zn

If 25 mL of 0 05 N NaOH required 30 mL of sulfuric acid for titration What is the normality of the acid

Using the image below select the word that best completes the sentence In the following reaction Compound A is the Select and Compound B is the Select Compound A H Compound B I H Compound C

12 What is the main function of a CMA a The report assists the seller in finding buyers interested in purchasing a home b The report assists the buyer or seller in determining the proper list price and fa just the buyer the proper offer price c The report shows the comparable prices of homes in a neighborhood d The report assists the buyer in finding homes available to purchase

A student places 5 3 g of a solid substance into a test tube and heats it up After heating it and then letting it cool they weigh the substance again To their surprise the mass is now 3 6 g In a few sentences explain to the student which type of reaction this likely was and also explain how this relates to mass conservation Explain to the student why they experiences a decrease in mass

32p has a half life of 14 3 days The original sample of 32P has a mass of 1 88 g Approximately what mass of P 32 will remain after 6 half lives 0 188 g O 0 0294 g O None of the answers are correct 0 0588 g 0 352 g 0 101 g

20 The group of prospects who can be considered potential buyers is called what a scarious b buyer demographic c buyer pool d potential buyers

Select one A chemist mixed Liquid A and Liquid B together A solid formed in the bottom of the container The chemist dried the solid material and weighed it The data table shows all of the material masses Mixing Experiment O Substance Liquid A Liquid B O Solid Based on this data how much liquid C was in the container with the solid after the materials were mixed 100 grams O 0 grams 200 grams Mass O 300 grams 100 grams 100 grams 100 grams LIQUID ALIQUID B SOLID LIQUID C

These equations represent the results of dissolving different substances in water Identify each substance as a strong electrolyte weak electrolyte or nonelectrolyte NH4 SO4 s 2NH4 aq SO4 aq CuSO4 s Cu aq SO4 aq HF g H O H3O aq F aq C3H6O C3H6O aq DONE

Which one s of the following are examples of a chemical change 1 A copper roof developing a green patina over time 2 A match burning 3 Ethanol evaporating 4 Both A and B are examples of chemical changes 5 A B and C are all examples of chemical changes

Helium s boiling point is 4 222 K Calculate helium s boiling point in degrees Fahrenheit 1 467 3 F 2 167 2 F 3 452 1 F 4 452 1 F 5 467 3 F

A sloth is the slowest moving mammal and travels at a top speed of 0 15 mph If a sloth traveled for 37 minutes without stopping how many inches total will the sloth have moved total Use the following conversion factors to help guide you 3 ft 1 yd 60 min 1 hr 12 in 1 ft 1 mi 1760 1 158 4 in 2 0 0053 in 3 5860 8 in 4 1953 6 in 5 5 55 in

ch two atoms have the same number of neutrons 34 16 S 32S 35Cl 38 Ar S 16 17 18 34 32 a S and S 16 16 b C 34 16 38 S and A Ar 35 34 S and C 16 17 d 35 Cl and 38 18 Ar

The density of mercury is 13 534 g mL What volume in L does 680 g occupy 1 50 L 2 0 050 L 3 9203 L 4 0 02 L 5 0 0002 L

Select the correct sequence of events in the scientific method 1 thesis observation experiment theory scientific law 2 theory observation scientific law 3 observation hypothesis experiment theory scientific law 4 hypothesis experiment theory scientific law 5 observation hypothesis experiment theory

A pure substance composed of two or more different elements is 1 an ion 2 a homogeneous mixture O 3 a chemical compound 4 a solid O 5 5 an atom

Student 1 Density 0 998 g mL Student 2 Density 0 996 g mL Student 3 Density 0 996 g mL The actual density of water at 25 C equal 0 997 g mL What do the results of these three experiments demonstrate when compared to the true density of water 1 High accuracy and high precision 2 High accuracy and low precision 3 Low accuracy and high precision 4 Low accuracy and low precision

A 20 g sample of calcium carbonate decomposes in a flame to produce carbon dioxide gas and 11 2 g of calcium oxide How much carbon dioxide was released in the decomposition 1 0 2 g O2 20 g 3 11 2 g 4 28 8 g 5 8 8 g

A buffer solution that is 0 466 M in HCIO and 0 466 M in NaClO has a pH of 7 46 The addition of 0 01 mol of OH to 1 0 L of this buffer would cause the pH to The capacity of this buffer for added H O could be increased by the addition of 0 141 mol

Which of the following compounds has the lowest C C stretching frequency cm A O A OB X OC B C X D E

The number of signals and their splitting in the H NMR spectrum of the molecule below is 3 signals 2 doublets and a septet 2 signals a doublet and a septet O3 signals a doublet a quartet and a septet O4 signals 2 doublets a singlet and a septet 3 signals a singlet a doublet and a septet

If a molecule contains 4 elements of unsaturation degree of unsaturation and H NMR peaks are between 7 0 8 0 ppm what structural group is likely to be present carbonyl group O hydroxyl group cyclohexyl ring aromatic ring

Which of the indicated bonds would be expected to show IR peak H CH3 C C HAH A H CEC H O A only OB only O Both A and B O Neither A nor B B

Calculate E for the cell below using the correct half reactions Fe 2 2e Fe E 0 440 Would this cell be spontaneous as written Zn 2 aq 2Fe 2 aq 2Fe 3 aq Zn s Cell potential to two decimal places Spontaneous yes or no Fe 3 1e Fe 2 EO 0 771 Zn 2 2e Zn E 0 763

Given the electrochemical reaction shown if the standard reduction potential of Ni2 Ni is 0 26 V and the standard reduction potential of Al Al is 1 66V what is E for the following Al Al aq Ni 2 aq Ni E V

How much of a 12 0 M HCl solution do you need in order to make 200 mL of a 2 4 M HCI solution How nuch water must be added to make the solution ml 12 0 M HCI

Potassium chlorate KCIO3 decomposes when heated to produce potassium chloride and oxygen gas 513 14g of potassium chlorate is decomposed If the temperature of the room is 25 C and the pressure is 1 2atm what volume of oxygen gas is formed

A person reacts 85 31g of oxygen gas O with excess aluminum metal according to the reaction below What mass in grams of aluminum oxide Al2O3 will form Reaction 4Al s 302 g 2Al O3 s

A person reacts 83 27g of oxygen gas O with excess aluminum metal according to the reaction below What mass in grams of aluminum oxide Al2O3 will form Reaction 4Al s 302 g 2Al2O3 s

A person reacts 9 89mol of nitrogen gas with 7 92mol of hydrogen gas What volume of ammonia NH3 is likely to form if the temperature of the reaction is 26 81 C and the pressure in the room is 2 06atm Reaction N2 g 3H2 g 2NH3 g You will be asked to upload a photo of your work for this problem

A sample of oxygen gas is at 7 88atm of pressure has a volume of 13 39L and is at a temperature of 44 62 C How many particles in moles of oxygen gas are in the sample

If a scientist has 562 79g of aluminum oxide Al2O3 How many particles in moles do they have

A person reacts 241 45g of oxygen gas O with 159 82g of aluminum metal according to the reaction below What mass in grams of aluminum oxide Al2O3 will form Reaction 4Al s 302 g 2Al2O3 s