Problem 31
Carry out these conversions: (a) \(22.6 \mathrm{~m}\) to decimeters, (b) 25.4 mg to kilograms.
Problem 32
Carry out these conversions: (a) 242 lb to milligrams, (b) \(68.3 \mathrm{~cm}^{3}\) to cubic meters.
Problem 33
The price of gold on a certain day in 2004 was \(\$ 315\) per troy ounce. How much did \(1.00 \mathrm{~g}\) of gold cost that day? \((1\) troy ounce \(=31.03 \mathrm{~g} .)\)
Problem 34
How many seconds are in a solar year \((365.24\) days \() ?\)
Problem 35
How many minutes does it take light from the sun to reach Earth? (The distance from the sun to Earth is 93 million mi; the speed of light \(=3.00 \times\) \(\left.10^{8} \mathrm{~m} / \mathrm{s} .\right)\)
Problem 36
A slow jogger runs a mile in \(13 \mathrm{~min} .\) Calculate the speed in (a) in/s, (b) \(\mathrm{m} / \mathrm{min}\), (c) \(\mathrm{km} / \mathrm{h} .(1 \mathrm{mi}=1609 \mathrm{~m}\) \(1 \mathrm{in}=2.54 \mathrm{~cm} .)\)
Problem 37
Carry out these conversions: (a) A 6.0-ft person weighs 168 lb. Express this person's height in meters and weight in kilograms. \((1 \mathrm{lb}=453.6 \mathrm{~g} ; 1 \mathrm{~m}=\) \(3.28 \mathrm{ft} .)\) (b) The current speed limit in some states in the United States is 55 miles per hour. What is the speed limit in kilometers per hour? (c) The speed of light is \(3.0 \times 10^{10} \mathrm{~cm} / \mathrm{s}\). How many miles does light travel in 1 hour? (d) Lead is a toxic substance. The "normal" lead content in human blood is about 0.40 part per million (that is, \(0.40 \mathrm{~g}\) of lead per million grams of blood). A value of 0.80 part per million (ppm) is considered to be dangerous. How many grams of lead are contained in \(6.0 \times 10^{3} \mathrm{~g}\) of blood (the amount in an average adult) if the lead content is \(0.62 \mathrm{ppm} ?\)
Problem 39
Aluminum is a lightweight metal (density \(=2.70\) \(\mathrm{g} / \mathrm{cm}^{3}\) ) used in aircraft construction, high-voltage transmission lines, and foils. What is its density in \(\mathrm{kg} / \mathrm{m}^{3} ?\)
Problem 40
The density of ammonia gas under certain conditions is \(0.625 \mathrm{~g} / \mathrm{L} .\) Calculate its density in \(\mathrm{g} / \mathrm{cm}^{3}\).
Problem 41
Which of these describe physical and which describe chemical properties? (a) Iron has a tendency to rust. (b) Rainwater in industrialized regions tends to be acidic. (c) Hemoglobin molecules have a red color. (d) When a glass of water is left out in the sun, the water gradually disappears. (e) Carbon dioxide in air is converted to more complex molecules by plants during photosynthesis.
