Explore BrainMass

various chemical questions

Please see the attached file for the fully formatted problems.
1. If a muscle tissue sample is 125 microns thick, what is the thickness in inches? (Given: 1 micron = 3.94 x 10^-5 inches)

3. If a patient is injected with 0.500 L of I.V. liquid, what is the volume in quarts? (Given: 1 quart = 0.946 L)

5. BONUS (4 pts): Exhaust fans report speeds in cfm (cubic feet per minute). An effective bathroom exhaust fan replaces all the air in a bathroom at a rate of 8 times per hour. If a bathroom has a volume of 405 ft3, then what is the minimum speed fan needed for this bathroom?

6. The average distance from the earth to the moon is 238,857 miles. Express this number in scientific notation, and round to 3 significant digits.

7. Write 30501000 in proper scientific notation.

8. Using the rules of significant figures, calculate the following: 6.167 + 70 = ?

9. Express 3.62 x 10^4 m as an ordinary number.
10. Express 9.010 x 10-3 kg as an ordinary number.
11. A plastic object with a density of 1.43 g/mL is placed into a container of water. What will most likely happen?
12. A gold nugget is placed into a graduated cylinder containing water, and the level rises from 10.5 mL to 14.8 mL. What is the volume of the nugget?
13. A cube of wood measuring 10.0 cm on each side has a mass of 846.2 g. Calculate the density of the wood.
14. An experiment requires 75.0 g of ethyl alcohol (density = 0.790 g/mL). What volume, in L, will be required?
15. Which one of the following represent an exact quantity?
16. In 2.0 years, Voyager2 traveled about 4.4 billion miles. Determine the average speed of Voyager2 in miles per hour (mi/h).
19. Aqueous solutions of the substance nickel (II) sulfate are bright green in color. If an aqueous solution of barium chloride is added to an aqueous solution of nickel (II) sulfate, a white precipitate of barium sulfate forms.
From the information above, indicate one physical property of nickel (II) sulfate in solution.
21. Classify the following as a physical or chemical change:
An antacid tablet fizzes and releases carbon dioxide gas when it comes in contact with hydrochloric acid in the stomach.
22. Classify the following as a physical or chemical change:
A piece of rubber stretches when pulled upon.
23. Classify the following as a physical or chemical change:
Rubbing alcohol evaporates quickly from the skin.
24. Balance the following chemical equation:
PCl3 + H2O ----> H3PO3 + HCl
25. Balance the following chemical equation:
Pb(NO3)2 + K2CrO4 ----> PbCrO4 + KNO3
26. When two aqueous solutions are mixed together, the solution turns cloudy. Did a chemical reaction occur? Why or why not?
27. Consider the following double displacement reaction:
Ca(NO3)2(aq) + NaBr(aq) ---> ???
No heat exchange is observed.
Does this reaction occur? If so, write the completed balanced reaction.
If not, explain why no reaction occurs.
(Hint: to determine if rxn occurs (or not), the first step is to determine the potential products formed from this reaction and then consider the "evidence for chemical reactions".) Show all work/reasoning.
28. Sulfur reacts with fluorine gas to produce sulfur hexafluoride:

S(l) + 3F2(g) ---> SF6(g)

How many grams of fluorine gas must react to give 9.26 g of sulfur hexafluoride?
29. At high temperatures, sulfur combined with iron to form brown-black iron(II) sulfide, according to the balanced equation:<br><br>Fe(s) + S(l) ---> FeS(s)<br><br>
In an experiment, 5.00 g of iron reacts with excess sulfur to produce 6.29 g of iron(II) sulfide. The maximum amount of iron((() sulfide that can be produced is 7.87 g.<br><br>From reading the problem (no calculations necessary; read the problem carefully), what is the theoretical yield of FeS(s)?
30. Calculate the theoretical yield by dimensional analysis.
32. A 1.640-mg sample of NaCl (molar mass = 58.44 g/mol) is dissolved in enough water to make 0.00175 L of solution. Calculate the molarity of the resulting solution. (Watch sig figs.)
33. What mass of solute is contained in 417 mL of a 0.314 M magnesium fluoride solution?
34. Which of the following represents units of molarity?
35. What is usually true regarding the solubility of a solid in a solvent with respect to temperature?
36. What is the term for solution that contains the maximum amount of solute that can be dissolved at a given temperature?
37. What is the term for the component of a solution that is the lesser quantity?
38. Determine the concentration of a solution made by dissolving 10.0 g of sodium chloride in 750.0 mL solution.
39. Calculate the mass of silver nitrate (in g) in a 145 mL solution of 4.31 M AgNO3
40. What volume of 0.550 M solution of potassium hydroxide can be made with 25.0 g of potassium hydroxide?
41. What volume of 18.0 M H<sub>2</sub>SO<sub>4</sub> is required to prepare 12.0 L of 0.156 M sulfuric acid?<hint: Use the Dilution formula>
43. When a certain sample of matter is placed into a closed container, its molecules fill the entire volume of the container. This sample of matter must be a:
44. A sample of matter exhibiting a high degree of structure would most likely be
45. What type of intermolecular forces exist between molecules of carbon tetrachloride, CCl4
46. Which one of the following molecules has dipole forces?


Solution Summary

It provides detailed explanations to various chemical questions, such as scientific notation, significant number, balancing equations, and intermolecular forces, etc. The solution received a '5/5' rating from the student who posted the questions originally.