Chapter 1

How does a hypothesis differ from a scientific theory?

How does a hypothesis become a theory?

Describe how Dalton's atomic theory supported his law of multiple proportions.

Why was the belief that matter consists of atoms a philosophy in ancient Greece but was considered a theory in the early 1800 s?

Describe a chemical reaction that produces two compounds whose compositions illustrate Dalton's law of multiple proportions.

Describe how a scientific theory differs from the meaning of \(theory\) as it is used in normal conversation.

Can a theory be proven?

Which of the following foods is a heterogeneous mixture? (a) bottled water; (b) a Snickers bar; (c) grape juice; (d) an uncooked hamburger

Which of the following foods is a homogeneous mixture? (a) freshly brewed coffee; (b) vinegar; (c) a slice of white bread; (d) a slice of ham

Which of the following foods is a heterogeneous mixture? (a) apple juice; (b) cooking oil; (c) solid butter; (d) orange juice; (e) tomato juice

Which of the following is a homogeneous mixture? (a) a bronze sword from ancient Greece; (b) sweat; (c) Nile River water; (d) gasoline; (e) compressed air in a scuba tank.

Filters can be used to remove suspended particles of soil from drinking water. Would distillation also remove these particles? If so, suggest a reason why it is not widely used.

List one chemical and four physical properties of gold.

Describe three physical properties that gold and silver have in common and three physical properties that distinguish them.

Give three properties that enable a person to distinguish between table sugar, water, and oxygen.

Give three properties that enable a person to distinguish between table salt, sand, and copper.

Indicate whether each of the following properties is a physical or chemical property of sodium (Na): a. Its density is greater than that of kerosene and less than that of water. b. It has a lower melting point than most other metals. c. It is an excellent conductor of heat and electricity. d. It is soft and can be easily cut with a knife. e. Freshly cut sodium is shiny, but it rapidly tarnishes when it comes in contact with air. f. It reacts very vigorously with water, releasing hydrogen \(\operatorname{gas}\left(\mathrm{H}_{2}\right)\)

Indicate whether each of the following is a physical or chemical property of hydrogen gas \(\left(\mathrm{H}_{2}\right):\) a. At room temperature, its density is less than that of any other gas. b. It reacts vigorously with oxygen \(\left(\mathrm{O}_{2}\right)\) to form water. c. Liquefied \(\mathrm{H}_{2}\) boils at \(-253^{\circ} \mathrm{C}\) d. \(\mathrm{H}_{2}\) gas does not conduct electricity.

Can an extensive property be used to identify a substance? Explain why or why not.

Which of the following are intensive properties of a sample of a substance? (a) freezing point; (b) heat content; (c) temperature

Is the capacity of carbon dioxide to extinguish fires linked to its chemical properties, its physical properties, or both? Explain your answer.

The stainless steel used to make kitchen knives and many other tools gets its name from its capacity to resist corrosion and, therefore, stain less. Is this a chemical or physical property of stainless steel?

In what ways are the arrangements of water molecules in ice and liquid water similar and in what ways are they different?

What occupies the space between the particles that make up a gas?

Substances have characteristic triple points, unique combinations of temperature and pressure at which substances can simultaneously exist as solids, liquids, and gases. In which of these three states do the particles of a substance at its triple point have the greatest motion and in which state do they have the least motion?

A pot of water on a stove is heated to a rapid boil. Identify the gas inside the bubbles that forms in the boiling water.

A brief winter storm leaves a dusting of snow on the ground. During the sunny but very cold day after the storm, the snow disappears even though the air temperature never gets above freezing. If the snow didn't melt, where did it go?

Equal masses of water undergo condensation, deposition, evaporation, and sublimation. a. Which of the processes is accompanied by the release of the greatest amount of energy? b. In which of the processes is the greatest amount of energy absorbed?

How are energy and work related?

Explain the difference between potential energy and kinetic energy.

Which of the following statements about heat are true? a. Heat is the transfer of energy from a warmer place to a cooler one. b. Heat flows faster from a full container of hot coffee than a half-full container of coffee at the same temperature. c. A cup of hot coffee loses heat faster than the same cup full of warm coffee.

Describe three examples of energy transfer that happen when you speak on a cell phone to a friend.

Describe in general terms how the SI and U.S. customary systems of units differ.

Both the Fahrenheit and Celsius scales are based on reference temperatures that are 100 degrees apart. Suggest a reason why the Celsius scale is preferred by scientists.

In what way are the Celsius and Kelvin scales similar and in what way are they different?

What is meant by an absolute temperature scale?

Can a temperature in "C ever have the same value in ' \(\mathrm{F} ?\)

Olympic Mile An Olympic "mile" is actually 1500 m. What percentage is an Olympic mile of a U.S. mile \((5280 \mathrm{ft}) ?\)

A sport-utility vehicle has an average mileage rating of 18 miles per gallon. How many gallons of gasoline are needed for a 389 -mile trip?

A single strand of natural silk may be as long as \(4.0 \times 10^{3} \mathrm{m}\) What is this length in miles?

The speed of light in a vacuum is \(2.998 \times 10^{8} \mathrm{m} / \mathrm{s} .\) What is the speed of light in \(\mathrm{km} / \mathrm{h}\) ?

If a wheelchair-marathon racer moving at 13.1 miles per hour expends energy at a rate of 665 Calories per hour, how much energy in Calories would be required to complete a marathon race ( 26.2 miles) at that pace?

To qualify to run in the 2016 Boston Marathon, a distance of 26.2 miles, an 18 -year-old woman had to have completed another marathon in 3 hours and 35 minutes or less. Translate this qualifying time and distance into average speeds expressed in (a) miles per hour and (b) meters per second.

At a distance of 4.3 light-years, Proxima Centauri is the nearest star to our solar system. What is the distance to Proxima Centauri in kilometers? (The speed of light in space is \(2.998 \times 10^{8} \mathrm{m} / \mathrm{s} .\) )

The level of water in an Olympic-size swimming pool \((50.0 \mathrm{m} \text { long, } 25.0 \mathrm{m} \text { wide, and about } 2 \mathrm{m}\) deep ) needs to be lowered \(3.0 \mathrm{cm} .\) If water is pumped out at a rate of \(5.2 \mathrm{L}\) per second, how long will it take to lower the water level \(3.0 \mathrm{cm} ?\)

The price of a popular soft drink is \(\$ 1.00\) for 24 fluid ounces \((\mathrm{fl} \text { oz })\) or \(\$ 0.75\) for \(0.50 \mathrm{L}\). Which is a better buy? \((1 \mathrm{qt}=32 \mathrm{floz})\)

Suppose a runner completes a \(10 \mathrm{K}(10.0 \mathrm{km})\) road race in 41 minutes and 23 seconds. What is the runner's average speed in meters per second?

In 1973 a horse named Secretariat ran the fastest Kentucky Derby in history, taking 1 minute and 59.4 seconds to run 1.25 miles. What was Secretariat's average speed in (a) miles per hour and (b) meters per second?

A chemist needs \(35.0 \mathrm{g}\) of concentrated sulfuric acid for an experiment. The density of concentrated sulfuric acid at room temperature is \(1.84 \mathrm{g} / \mathrm{mL}\). What volume of the acid is required?

What is the mass of \(65.0 \mathrm{mL}\) of ethanol? (Its density at room temperature is \(0.789 \mathrm{g} / \mathrm{mL} .\) )