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Problem 75g
Give the derived SI units for each of the following quantities in base SI units: (g) energy = mass × (velocity)2
Problem 77a
The distance from Earth to the Moon is approximately 240,000 mi. (a) What is this distance in meters?
Problem 77c
The distance from Earth to the Moon is approximately 240,000 mi. (c) The speed of light is 3.00 ⨉ 108 m/s. How long does it take for light to travel from Earth to the Moon and back again?
Problem 77d
The distance from Earth to the Moon is approximately 240,000 mi. (d) Earth travels around the Sun at an average speed of 29.783 km/s. Convert this speed to miles per hour.
Problem 78
Which of the following would you characterize as a pure or nearly pure substance?
a. baking powder
b. lemon juice
c. propane gas, used in outdoor gas grills
d. aluminum foil
e. ibuprofen
f. bourbon whiskey
g. helium gas
h. clear water pumped from a deep aquifer
Problem 81
An Olympic swimming pool is 164 ft long and 82 ft wide. Assume that it is filled to a depth of 3.0 m, which is the Olympic recommendation.
a. What volume of water in gal is needed to fill the pool?
b. What volume of water in L is needed to fill the pool?
c. The U.S. Geological Survey estimates that in 2015 U.S. domestic use of water was 82 gal/day per person. Using this value for daily usage, for what length of time could the water used to fill an Olympic swimming pool provide the domestic water usage for a community of 25,000 residents?
Problem 82b
A watt is a measure of power (the rate of energy change) equal to 1 J/s. (b) An adult person radiates heat to the surroundings at about the same rate as a 100-watt electric incandescent light bulb. What is the total amount of energy in kcal radiated to the surroundings by an adult over a 24 h period?
- By using estimation techniques, determine which of the following is the heaviest and which is the lightest: a 10-lb bag of fertilizer, a 10-kg bag of rice, or 2 gal of olive oil (density = 0.918 g/cm³).
Problem 83
- Hexane 1density = 0.659 g/mL2 and acetic acid 1density = 1.0446 g/mL2 do not form a solution when mixed but separate into distinct layers. A piece of oak wood 1density = 900 kg/m32 is placed inside a test tube containing hexane and acetic acid; sketch how the three substances would position themselves.
Problem 84
Problem 85a
Two spheres of equal volume are placed on the scales as shown. a. Which one is more dense?
Problem 88
A 32.65-g sample of a solid is placed in a flask. Toluene, in which the solid is insoluble, is added to the flask so that the total volume of solid and liquid together is 50.00 mL. The solid and toluene together weigh 58.58 g. The density of toluene at the temperature of the experiment is 0.864 g/mL. What is the density of the solid?
Problem 90
Automobile batteries contain sulfuric acid, which is commonly referred to as “battery acid.” Calculate the number of grams of sulfuric acid in 1.00 gal of battery acid if the solution has a density of 1.28 g/mL and is 38.1% sulfuric acid by mass.
- In 2005, J. Robin Warren and Barry J. Marshall shared the Nobel Prize in Medicine for discovering the bacterium Helicobacter pylori and for establishing experimental proof that it plays a major role in gastritis and peptic ulcer disease. The story began when Warren, a pathologist, noticed that bacilli were associated with the tissues taken from patients suffering from ulcers. Look up the history of this case and describe Warren’s first hypothesis. What sorts of evidence were required to establish a credible theory based on it?
Problem 93
Problem 97a
Judge the following statements as true or false. If you believe a statement to be false, provide a corrected version. (a) Air and water are both elements.
Problem 97b
Judge the following statements as true or false. If you believe a statement to be false, provide a corrected version. (b) All mixtures contain at least one element and one compound.
Problem 97c
Judge the following statements as true or false. If you believe a statement to be false, provide a corrected version. (c) Compounds can be decomposed into two or more other substances; elements cannot.
Problem 97d
Judge the following statements as true or false. If you believe a statement to be false, provide a corrected version. (d) Elements can exist in any of the three states of matter.
Problem 97g
Judge the following statements as true or false. If you believe a statement to be false, provide a corrected version. (g) The number 0.0033 has more significant figures than 0.033.
Problem 97i
Judge the following statements as true or false. If you believe a statement to be false, provide a corrected version. (i) Compounds always contain at least two different elements.
Problem 98
You are assigned the task of separating a desired granular material with a density of 3.62 g/cm3 from an undesired granular material that has a density of 2.04 g/cm3. You want to do this by shaking the mixture in a liquid in which the heavier material will fall to the bottom and the lighter material will float. A solid will float on any liquid that is more dense. Using an Internet-based source or a handbook of chemistry, find the densities of the following substances: carbon tetrachloride, hexane, benzene, and diiodomethane. Which of these liquids will serve your purpose, assuming no chemical interaction takes place between the liquid and the solids?
Problem 99b
In 2009, a team from Northwestern University and Western Washington University reported the preparation of a new 'spongy' material composed of nickel, molybdenum, and sulfur that excels at removing mercury from water. The density of this new material is 0.20 g/cm3, and its surface area is 1242 m2 per gram of material. (b) Calculate the surface area for a 10.0-mg sample of this material.