Chapter 1, Problem 1.76E

A person weighed 15 pennies on a balance and recorded the following masses: 3.112 g 3.109 g 3.059 g 2.467 g 3.079 g 2.518 g 3.129 g 2.545 g 3.050 g 3.053 g 3.054 g 3.072 g 3.081 g 3.131 g 3.064 g Curious about the results, he looked at the dates on each penny. Two of the light pennies were minted in 1983 and one in 1982. The dates on the 12 heavier pennies ranged from 1970 to 1982. Two of the 12 heavier pennies were minted in 1982. a. Do you think the Bureau of the Mint changed the way it made pennies? Explain. b. The person calculated the average mass of the 12 heavy pennies. He expressed this average as 3.0828 g 0.0482 g. What is wrong with the numbers in this result, and how should the value be expressed?

Precious metals and gems are measured in troy weights in the English system: 24 grains 1 pennyweight (exact) 20 pennyweight = 1 troy ounce (exact) 12 troy ounces 1 troy pound (exact) 1 grain = 0.0648 g 1 carat = 0.200 g a. The most common English unit of mass is the pound avoirdupois. What is 1 troy pound in kilograms and in pounds? b. What is the mass of a troy ounce of gold in grams and in carats? c. The density of gold is 19.3 g/cm3. What is the volume of a troy pound of gold?

A sample of vermilion-colored mineral was weighed in air, then weighed again while suspended in water. An object is buoyed up by the mass of the fluid displaced by the object. In air, the mineral weighed 18.49 g; in water, it weighed 16.21 g. The densities of air and water are 1.205 g/L and 0.9982 g/cm3, respectively. What is the density of the mineral?

For the masses and volumes indicated, calculate the density in grains per cubic centimeter. mass = 452.1 g: volume = 292 cm3 mass = 0.14 lb: Volume 125 mL mass = 1.01 kg; volume = 1000 cm3 mass = 225 mg: volume = 2.51 mL

For these questions, be sure to apply the rules for significant figures. a You are conducting an experiment where you need the volume of a box; you take the length, height, and width measurements and then multiply the values together to find the volume. You report the volume of the box as 0.310 m1. If two of your measurements were 0.7120 m and 0.52145 m, what was the other measurement? b If you were to add the two measurements from the first part of the problem to a third length measurement with the reported result of 1.509 m, what was the value of the third measurement?

Although the preferred SI unit of area is the square meter, land is often measured in the metric system in hectares (ha). One hectare is equal to 10,000 m2. In the English system, land is often measured in acres (1 acre = 160 rod2). Use the exact conversions and those given in Exercise 47 to calculate the following. a. 1 ha = __________ km2 b. The area of a 5.5-acre plot of land in hectares, square meters, and square kilometers c. A lot with dimensions 120 ft by 75 ft is to be sold for 6500. What is the price per acre? What is the price per hectare?

The longest river in the world is the Nile River with a length of 4145 mi. How long is the Nile in cable lengths, meters, and nautical miles? Use these exact conversions to help solve the problem: 6 ft = 1 fathom 100 fathoms = 1 cable length 10 cable lengths = 1 nautical mile 3 nautical miles = 1 league

An aluminum alloy used in the construction of aircraft wings has a density of 2.70 g/cm3. Express this density in SI units (kg/m3).

00 G. You have two objects made of the same substance. Object 1 is a cube with a mass of 246.5 g. You measure the side of the cube using a ruler and find it to be 3.17 cm. Object 2 is a sphere with a mass of 123.3 g. You find the volume of the sphere using water displacement. The volume of the water in a graduated cylinder initially is 120.0 mL, and when the sphere is added the new volume is 135.8 mL. Which one of the following is the best reason for the difference between the two calculated densities? A) Different numbers of significant figures were used in each measurement. B) Uncertainty in measurement associated with the equipment. C) Errors in how the density was calculated. D) The units used to measure the densities are not the same. o search a 77°F delete 114 144 5. 6. D.