# Deriving Unknown Chemical Compound

I'm having some problems identifying the unknown compound based upon the information given. I provided as much information as I could with a possible compound, but I don't think it is correct. Can you please help me?

Thanks!

An unknown compound containing C, H, and one kind of heteroatom only shows a molecular ion peak at m/z 184 and a peak of almost equal intensity at m/z 186 in the mass spectrum. The 1H and 13C NMR spectra of the compound are given on the following page. Propose a structure for the unknown compound and assign all peaks in the two NMR spectra.

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#### Solution Preview

Solution:

The molecular ion peaks at 184, which is the molecular weight of the compound. The m/z value of 186 is a parent peak.

C-13 spectra information

~18 ppm indicates alkane region (-CH3- groups).

~29 ppm also indicates alkane region (CH3 groups present).

~120 ppm indicates that the molecule could be aromatic with C=C bonds.

~130 ppm also indicates an ...

#### Solution Summary

This solution provides a prediction on what the unknown chemical compound may be, due to the H-spectra and C-13 spectra information given.

A Discussion on Various Chemical and Physical Science Concepts

1. The density of the liquid flowing through the horizontal pipe in the drawing above is 1500 kg/m3. The speed of the fluid at pint A is 5.5 m/s while at point B it is 8.0 m/s. What is the difference in pressure, PB - PA, between points B and A?

a.) -1.9 x 103 Pa

b.)+3.8 x 103 Pa

c.)-2.5 x 104 Pa

d.)+5.0 x 104 Pa

e.)-7.6 x 105 Pa

2. A balloon is released from a tall building. The total mass of the balloon including the enclosed gas is 2.0 kg. its volume is 5.0 m3. The density of air is 1.3 kg/m3. What is the average density of the balloon?

a.) 0.2 kg/m3

b.) 0.4 kg/m3

c.) 0.8 kg/m3

d.) 1.0 kg/m3

e.) 1.2 kg/m3

3. Which one of the following properties could not be used as a temperature sensitive property in the construction of a thermometer?

a.) The change in mass of a solid

b.) The change in volume of a liquid

c.) The change in length of a metal rod

d.) The change in electrical resistance of a wire

e.) The change in pressure of a gas at constant volume

4. A woman is enjoying a tropical drink while lying on a beach. The acceleration due to gravity at her location is 9.85 m/s2. What gauge pressure must exist in the woman's mouth if she is drinking through a straw extending 0.085 m above the surface of the drink? Note: Assume the drink has a density of 1015 kg/m3.

a.) 850 Pa

b.) 97 Pa

c.) 1100 Pa

d.) 100 Pa

e.) 1.0 2.0 x 105 Pa

5. A submarine is operating at 100.0 m below the surface of the ocean. If the air inside the submarine is maintained at a pressure of 1.0 atmosphere, what is the magnitude of the force that acts on the rectangular hatch 2.0 x 1.0 m on the deck of the submarine?

a.) 980 N

b.) 2.0 x 103 N

c.) 5.0 x 104 N

d.) 9.8 x 105 N

e.) 2.0 x 106 N

6. Which would cause a more serious burn: 30 g of steam or 30 g of liquid water, both at 100° C; and why is this so?

a.) Water, because it is denser than steam.

b.) Steam, because of its specific heat capacity

c.) Steam, because of its latent heat of vaporization.

d.) Water, because its specific heat is greater than that of steam

e.) Either one would cause a burn of the same severity since they are both at the same temperature.

7. A tanker ship is filled with 2.25 x 105 m3 of gasoline at a refinery in southern Texas when the temperature is 17.2° C. When the ship arrives in New York City, the temperature is 1.3° C. If the coefficient of volumetric expansion for gasoline is 9.50 x 10-4/C°, how much has the volume of the gasoline decreased when it is unloaded in New York?

a.) 1.50 x 10-2 m3

b.) 66.2 m3

c.) 1290 m3

d.) 3400 m3

e.) 1.05 x 104 m3

8. A soft drink manufacturer claims that a new diet drink is "low Joule." The label indicates the available energy is 6300 J. What is the equivalent of this energy in Calories (1 Calorie = 1000 cal)?

a.) 0.015 Cal

b.) 0.48 Cal

c.) 1.0 Cal

d.) 1.5 Cal

e.) 4.8 Cal

9. Water enters a pipe of diameter 3.0 cm with a velocity of 3.0 m/s. The water encounters a constriction where its velocity is 12 m/s. what is the diameter of the constricted portion of the pipe?

a.) 0.33 cm

b.) 0.75 cm

c.) 1.0 cm

d.) 1.5 cm

e.) 12 cm

10. The average density of the material in intergalactic space is approximately 2.5 x 10-27 kg/m3. What is the volume of a gold sample ρ, = 19 300 kg/m3, that has the same mass as 8.0 x 1024 m3 of intergalactic space?

a.) 1.0 x 10-6 m3

b.) 2.0 x 10-5 m3

c.) 5.0 x 10-5 m3

d.) 1.0 x 10-4 m3

e.) 8.0 x 10-5 m3

11. A small sculpture made of brass (ρbrass = 8470 kg/m3) is believed to have a secret central cavity. The weight of the sculpture in air is 15.76 N. When it is submerged in water, the weight is 13.86 N. What is the volume of the secret cavity?

a.) 1 x 10-4 m3

b.) 2 x 10-4 m3

c.) 3 x 10-5 m3

d.) 2 x 10-6 m3

e.) 4 x 10-6 m3

12.) An ice cube, ρ = 917 kg/m3, is sliding down a frictionless incline as shown in the drawing. The sides of the cube each have a length of 0.75 m. What pressure does the cube exert on the incline?

a.) 1800 Pa

b.) 6500 Pa

c.) 3600 Pa

d.) 2700 Pa

e.) 5100 Pa

13. The density of mercury is 1.36 x 104 kg/m3. What is the mass of a 4.00 10-4 -m3 sample of mercury?

a.) 0.0343 kg

b.) 0.002 94 kg

c.) 2.94 kg

d.) 5.44 kg

e.) 6.29 kg

14. Two cubes, one silver and one iron, have the same mass and temperature. A quantity Q of heat is removed from each cube. Which one of the following properties causes the final temperatures of the cubes to be different?

a.) Density

b.) Latent heat vaporization

c.) Specific heat capacity

d.) Coefficient of volume expansion

e.) Volume

15. Three thermometers are placed in a closed insulated box and are allowed to reach thermal equilibrium. One is calibrated in Fahrenheit degrees, one in Celsius degrees, and one in Kelvins. The Celsius thermometer reads -40° C and the Kelvin thermometer reads 233 K. Which one of the following statements is necessarily true?

a.) The Kelvin thermometer should read -233 K.

b.) The Kelvin thermometer should read -313 K.

c.) The Fahrenheit thermometer must read -40° F.

d.) If the water were found within the box, it must be in the liquid state.

e.) If the temperature of the contents is increased by 10° C, the reading on the Kelvin thermometer should increase by 273 K.

16. Two spheres, labeled A and B, have identical masses, but are made of different substances. The specific heat capacity of sphere A is 440 J/kg ?C° and that of sphere B is 160 J/kg ?C°. There spheres are initially at 21° C; and the same quantity of heat is added to each sphere. If the final temperature of sphere A is 72° C, what is the final temperature of sphere B?

a.) 160° C

b.) 140° C

c.) 111° C

d.) 51° C

e.) 39° C

17. Which one of the following statements is false concerning the derivation or usage of Bernoulli's equation?

a.) The fluid must be non-viscous.

b.) Streamline flow is assumed.

c.) The fluid must be incompressible.

d.) The work-energy theorem is used to derive Bernoulli's equation.

e.) Vertical distances are always measured relative to the lowest point within the fluid.

18. The coefficient of linear expansion of aluminum is 23 x 10-6/C°. A circular hole in an aluminum plate is 2.725 cm in diameter at 0° C. What is the diameter of the hole if the temperature of the plate is raised to 100° C?

a.) 0.0063 cm

b.) 2.728 cm

c.) 2.731 cm

d.) 2.757 cm

e.) 2.788 cm

19. Which one of the following temperatures is approximately equal to "room temperature?"

a.) 0 K

b.) 0° C

c.) 100° C

d.) 100 K

e.) 293 K

20. Which one of the following statements concerning streamline flow is true?

a.) At any given point in the fluid, the velocity is constant in time.

b.) Streamline flow occurs when there are sharp obstacles in the path of a fast-moving fluid.

c.) Streamline flow is described by Pascal's principle.

d.) Streamline flow is described by Archimedes' principle.

e.) The velocity vectors are the same for all particles in the fluid.

21. Determine the latent heat of vaporization of unknown substance X in kcal/g if 3.0 g of boiling liquid X are completely vaporized in 1.5 hours by an energy source of 10 kcal/h.

a.) 5 kcal/g

b.) 15 kcal/g

c.) 27 kcal/g

d.) 30 kcal/g

e.) 57.9 kcal/g

22. Zirconium tungstate is an unusual material because its volume shrinks with an increase in temperature for the temperature range 0.3 K to 1050 K (where it decomposes). In fact, the volumetric coefficient of thermal expansion is -26.4 x 10-6/K. Determine the ratio Δ V/V0 for the above mentioned temperature range. Express your answer in percent.

a.) -5.28 %

b.) -3.59 %

c.) -2.77 %

d.) -1.90 %

e.) -1.04 %

23. A balloon inflated with helium gas (density = 0.2 kg/m3) has a volume of 6 x 10-3 m3. if the density of air is 1.3 kg/m3, what is the buoyant force exerted on the balloon?

a.) 0.01 N

b.) 0.08 N

c.) 0.8 N

d.) 1.3 N

e.) 7.8 N

24. During an evening news broadcast in Helsinki, Finland, the meteorologist indicated that the day's lowest temperature was -4.0° C. What is the corresponding value of this temperature on the Fahrenheit scale?

a.) -7.2° F

b.) -4.0° F

c.) 17° F

d.) 25° F

e.) 39° F

25. A force of 250 N is applied to a hydraulic jack piston that is 0.01 m in diameter. If the piston which supports the load has a diameter of 0.10 m, approximately how much mass can be lifted by the force? Ignore any difference in height between the pistons.

a.) 255 kg

b.) 500 kg

c.) 800 kg

d.) 2550 kg

e.) 6300 kg

Please view the attached file for the original questions since some contain diagrams.

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