Chapter 1, Problem 1.65E

Two students were assigned to determine the mass of a sample of an unknown liquid. Student A used an ordinary laboratory balance that could determine mass to ±0.01 g. Student B used an analytical balance that could measure mass to ±0.1 mg. Each made four measurements, giving the following results: Student A: 8.19 g, 8.22 g, 8.21 g, 8.25 g Student B: 8.2210 g, 8.2210 g, 8.2209 g, 8.2210 g 2. Which student is more precise? A B

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?

Write the following measured quantities as you would record them using the correct number of significant figures based on the device used to make the measurements. a. Exactly 6mL of water measured with a graduated cylinder that has a smallest scale marking of 0.1mL b. A temperature that appears to be exactly 37 degrees using a thermometer with a smallest scale marking of 1C c. A time of exactly nine seconds measured with a stopwatch that has smallest scale marking of 0.1 second d. Fifteen and one-half degrees measured with a protractor that has 1- degree scale markings

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

1. ) Three 10 mL samples of gold weighs: 193.119 g, 193.122 g, and 193.161g, respectively. Which sample represents pure gold in terms of (density of pure gold : 19 . 32 g/mL ). 2.)  A stone has a mass of 12.3 g is added to a graduated cylinder filled with water to the 38.0 mL mark. After the solid sinks to the bottom, the water level is read to be at the 40.3 –mL mark. What is the density of the solid? 3.) A flask that contains 14. 59 mL liquid has a mass of 35. 66 g . What is the density of the liquid if the mass of an empty flask is 15. 67 g ?

1.) You have two objects made of the same substance. Object 1 is a cube with a mass of 180.1 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 90.1 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. Having found a density of 5.65 g/cm³ for the cube and a density of 5.70 g/mL for the sphere, which one of the following statements is true?   A) The density of the cube appears to be smaller than the sphere because the units used for the two density values are not the same. B) The density of the sphere and cube are not the same because their volumes and masses are different. C) The density of the sphere and cube are different because the shapes of the substance are different D) The density of the cube and sphere should be the same since they are made of the same substance.

A brick of metal has these dimensions:  7.07 in  x 9.20 in x 7.15 in.  It has mass 8.1 kg.  What is the density of the metal in g/cm3? 2.54 cm = 1 inch You need to write your answer in the box with one number past the decimal in regular non scientific notation.

Using the listed equalities, convert the following numbers to different units. Make sure that you have the correct number of significant figures. 1 inch = 2.54 cm, 1 foot = 12 inches, 1 mile = 5280 feet, 1 yard = 3 feet, 1 nautical mile = 1.852 kilometers, 1 oz = 28.35 grams,   1000 mg = 1 gram,   1000 grams = 1 kg,   1 m = 100 cm,   1 Km = 1000 m   1.825 x 105 ft = _________ Nautical miles 3.650 kg = ___________________ mg

A graduated cylinder was filled with water to the 25.0 mL mark and weighed. Its mass was 105.5g. An object made of an unknown metal was placed in the cylinder and completely submerged in the water. The water level rose to 30.7 mL. When reweighed, the cylinder, water and metal object had a total mass of 156.0g. Based on these measurement, what is the density of the unknown metal? 2.02 g/mL 5.08 g/mL 8.86 g/mL 1.64 g/mL