Chapter 1, Problem 1.97E

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?

A 15.5 g sample of sodium carbonate is added to a solution of acetic acid weighing 19.7 g. The two substances react, releasing carbon dioxide gas to the atmosphere. After reaction, the contents of the reaction vessel weigh 28.7 g. What is the mass of carbon dioxide given off during the reaction?

Some bottles of colorless liquids were being labeled when the technicians accidentally mixed them up and lost track of their contents. A 15.0-mL sample withdrawn from one bottle weighed 22.3 g. The technicians knew that the liquid was either acetone, benzene, chloroform, or carbon tetrachloride (which have densities of 0.792 g/cm3, 0.899 g/cm3, 1.489 g/cm3, and 1.595 g/cm3, respectively). What was the identity of the liquid?

Which of the following represent physical properties or changes, and which represent chemical properties or changes? You curl your hair with a curling iron. You curl your hair by getting a “permanent wave” at the hair salon. Ice on your sidewalk melts when you put salt on it. A glass of water evaporates overnight when it is left on the bedside table. Your steak chars if the skillet is too hot. Alcohol feels cool when it is spilled on the skin. Alcohol ignites when a flame is brought near it. Baking powder causes biscuits to rise.

3.37 If atypical grain of sand occupies a volume of 1.3 × 10-4 cm3, what is the volume (in cm3) of 1 mole of sand (ignoring the space between grains)? What is the volume in liters?

Vanadium metal is added to steel to impart strength. The density of vanadium is 5.96 g/cm3. Express this in SI units (kg/m3).

An elderly patient is prescribed 60 mg flurbiprofen to manage pain from rheumatoid arthritis. The smallest weighable quantity of the compounding pharmacy's scale is 210 mg. Using the aliquot method, what is the smallest total weight of the diluentthat you could add to the mixture?

a student obtains a sample of a sand/salt mixture in a test tube. home weighs the test tube with the sample and finds the mass to be 20.70 grams. He pours half of the mixture into a beaker and weighs the test tube and finds the mass to be 15.50 grams. how much of the sand salt mixture is in the beaker?

The shattered glass case at the scene of a jewelry store robbery was determined to be made of potash borosilicate glass, which has a density of 2.162g/mL. A 4.034g glass fragment was recovered from a suspect's clothing. When the fragment was placed into a graduated cylinder filled with water, 1.63mL of the water was displaced. Calculate the density of the glass fragment.