Chapter 1

Give the name of each of the following elements: (a) \(\mathrm{C}\) (b) \(\mathrm{K}\) (c) \(\mathrm{Cl}\) (d) \(\mathrm{P}\) (e) \(\mathrm{Mg}\) (f) \(\mathrm{Ni}\)

Give the name of each of the following elements: (a) Mn (b) \(\mathrm{Cu}\) (c) \(\mathrm{Na}\) (d) \(\mathrm{Br}\) (e) \(\mathrm{Xe}\) (f) \(\mathrm{Fe}\)

Give the symbol for each of the following elements: (a) barium (b) titanium (c) chromium (d) lead (e) arsenic (f) zinc

Give the symbol for each of the following elements: (a) silver (b) aluminum (c) plutonium (d) tin (e) technetium (f) krypton

In each of the following pairs, decide which is an element and which is a compound. (a) \(\mathrm{Na}\) and \(\mathrm{NaCl}\) (b) sugar and carbon (c) gold and gold chloride

In each of the following pairs, decide which is an element and which is a compound. (a) \(\mathrm{Pt}\left(\mathrm{NH}_{3}\right)_{2} \mathrm{Cl}_{2}\) and \(\mathrm{Pt}\) (b) copper or copper(II) oxide (c) silicon or sand

In each case, decide whether the underlined property is a physical or chemical property. (a) The normal color of elemental bromine is orange. (b) Iron turns to rust in the presence of air and water. (c) Hydrogen can explode when ignited in air. (d) The density of titanium metal is \(4.5 \mathrm{g} / \mathrm{cm}^{3} .\) (e) Tin metal melts at \(505 \mathrm{K}\) (f) Chlorophyll, a plant pigment, is green.

In each case, decide whether the change is a chemical or physical change. (a) A cup of household bleach changes the color of your favorite T-shirt from purple to pink. (b) Water vapor in your exhaled breath condenses in the air on a cold day. (c) Plants use carbon dioxide from the air to make sugar. (d) Butter melts when placed in the sun.

Which part of the description of a compound or element refers to its physical properties and which to its chemical properties? (a) The colorless liquid ethanol burns in air. (b) The shiny metal aluminum reacts readily with orange, liquid bromine.

Which part of the description of a compound or element refers to its physical properties and which to its chemical properties? (a) Calcium carbonate is a white solid with a density of \(2.71 \mathrm{g} / \mathrm{cm}^{3} .\) It reacts readily with an acid to produce gaseous carbon dioxide. (b) Gray, powdered zinc metal reacts with purple iodine to give a white compound.

Ethylene glycol, \(\mathrm{C}_{2} \mathrm{H}_{6} \mathrm{O}_{2},\) is an ingredient of automobile antifreeze. Its density is \(1.11 \mathrm{g} / \mathrm{cm}^{3}\) at \(20^{\circ} \mathrm{C}\). If you need exactly \(500 .\) mL of this liquid, what mass of the compound, in grams, is required?

A piece of silver metal has a mass of \(2.365 \mathrm{g} .\) If the density of silver is \(10.5 \mathrm{g} / \mathrm{cm}^{3},\) what is the volume of the silver?

A chemist needs \(2.00 \mathrm{g}\) of a liquid compound with a density of \(0.718 \mathrm{g} / \mathrm{cm}^{3} .\) What volume of the compound is required?

The cup is a volume measure widely used by cooks in the United States. One cup is equivalent to 237 mL. If 1 cup of olive oil has a mass of \(205 \mathrm{g}\), what is the density of the oil (in grams per cubic centimeter)?

Iron pyrite is often called "fool's gold" because it looks like gold (see page 19 ). Suppose you have a solid that looks like gold, but you believe it to be fool's gold. The sample has a mass of \(23.5 \mathrm{g} .\) When the sample is lowered into the water in a graduated cylinder (see Study Question 15 ), the water level rises from \(47.5 \mathrm{mL}\) to \(52.2 \mathrm{mL}\). Is the sample fool's gold \(\left(d=5.00 \mathrm{g} / \mathrm{cm}^{3}\right)\) or "real" gold \(\left(d=19.3 \mathrm{g} / \mathrm{cm}^{3}\right) ?\)

Many laboratories use \(25^{\circ} \mathrm{C}\) as a standard temperature. What is this temperature in kelvins?

The temperature on the surface of the sun is \(5.5 \times 10^{3}\) ' \(\mathrm{C}\) What is this temperature in kelvins?

Make the following temperature conversions: $$\begin{array}{ll} \hline \mathrm{C} & \mathrm{K} \\ \hline \text { a) } 16 & \\ \text { (b) } & 370 \\ \text { (c) } 40 & \\ \text {} \end{array}$$

Make the following temperature conversions: $$\begin{array}{ll} \hline \mathrm{C} & \mathrm{K} \\ \hline \text { a) } & 77\\\ \text { (b) } 63 & \\ \text { (c) } & 1450 \\ \text {} \end{array}$$

A marathon race covers a distance of \(42.195 \mathrm{km} .\) What is this distance in meters? In miles?

The average lead pencil, new and unused, is \(19 \mathrm{cm}\) long. What is its length in millimeters? In meters?

A standard U.S. postage stamp is \(2.5 \mathrm{cm}\) long and \(2.1 \mathrm{cm}\) wide. What is the area of the stamp in square centimeters? In square meters?

A compact disk has a diameter of \(11.8 \mathrm{cm} .\) What is the surface area of the disk in square centimeters? In square meters? [Area of a circle \(\left.=(\pi) \text { (radius) }^{2} .\right]\)

A typical laboratory beaker has a volume of \(250 .\) mL. What is its volume in cubic centimeters? In liters? In cubic meters? In cubic decimeters?

Some soft drinks are sold in bottles with a volume of \(1.5 \mathrm{L}\) What is this volume in milliliters? In cubic centimeters? In cubic decimeters?

A book has a mass of \(2.52 \mathrm{kg} .\) What is this mass in grams?

A new U. S. dime has a mass of 2.265 g. What is this mass in kilograms? In milligrams?

You and your lab partner are asked to determine the density of an aluminum bar. The mass is known accurately (to four significant figures). You use a simple metric ruler to determine its size and calculate the results in A. Your partner uses a precision micrometer and obtains the results in \(B\). $$\begin{array}{ll} \hline \begin{array}{l} \text { Method A } \\ \left(\mathrm{g} / \mathrm{cm}^{3}\right) \end{array} & \begin{array}{l} \text { Method B } \\ \left(\mathrm{g} / \mathrm{cm}^{3}\right) \end{array} \\ \hline 2.2 & 2.703 \\ 2.3 & 2.701 \\ 2.7 & 2.705 \\ 2.4 & 5.811 \\ \hline \end{array}$$ The accepted density of aluminum is \(2.702 \mathrm{g} / \mathrm{cm}^{3}\). (a) Calculate the average density for each method. Should all the experimental results be included in your calculations? If not, justify any omissions. (b) Calculate the percent error for each method's average value. (c) Which method's average value is more precise? Which method is more accurate?

The accepted value of the melting point of pure aspirin is \(135^{\circ} \mathrm{C} .\) Trying to verify that value, you obtain the melting points of \(134^{\circ} \mathrm{C}, 136^{\circ} \mathrm{C}, 133^{\circ} \mathrm{C},\) and \(138^{\circ} \mathrm{C}\) in four separate trials. Your partner finds melting points of \(138^{\circ} \mathrm{C}, 137^{\circ} \mathrm{C}, 138^{\circ} \mathrm{C},\) and \(138^{\circ} \mathrm{C}\) (a) Calculate the average value and percent error for you and your partner. (b) Which of you is more precise? More accurate?

A piece of turquoise is a blue-green solid, and has a density of \(2.65 \mathrm{g} / \mathrm{cm}^{3}\) and a mass of \(2.5 \mathrm{g}\) (a) Which of these observations are qualitative and which are quantitative? (b) Which of these observations are extensive and which are intensive? (c) What is the volume of the piece of turquoise?

Eight observations are listed below. Which of these observations identify chemical properties? (a) Sugar is soluble in water. (b) Water boils at \(100^{\circ} \mathrm{C}\) (c) Ultraviolet light converts \(\mathrm{O}_{3}\) (ozone) to \(\mathrm{O}_{2}\) (oxygen). (d) Ice is less dense than water. (e) Sodium metal reacts violently with water. (f) \(\mathrm{CO}_{2}\) does not support combustion. (g) Chlorine is a yellow gas. (h) Heat is required to melt ice.

Neon, a gaseous element used in neon signs, has a melting point of \(-248.6^{\circ} \mathrm{C}\) and a boiling point of \(-246.1^{\circ} \mathrm{C}\) Express these temperatures in kelvins.

You can identify a metal by carefully determining its density (d). An unknown piece of metal, with a mass of \(2.361 \mathrm{g},\) is \(2.35 \mathrm{cm}\) long, \(1.34 \mathrm{cm}\) wide, and \(1.05 \mathrm{mm}\) thick. Which of the following is this element? (a) Nickel, \(d=8.90 \mathrm{g} / \mathrm{cm}^{3}\) (b) Titanium, \(d=4.50 \mathrm{g} / \mathrm{cm}^{3}\) (c) Zinc, \(d=7.13 \mathrm{g} / \mathrm{cm}^{3}\) (d) \(\operatorname{tin}, d=7.23 \mathrm{g} / \mathrm{cm}^{3}\)

A red blood cell has a diameter of \(7.5 \mu \mathrm{m}\) (micrometers). What is this dimension in (a) meters, (b) nanometers, and (c) picometers?

Which occupies a larger volume, \(600 .\) g of water (with a density of \(0.995 \mathrm{g} / \mathrm{cm}^{3}\) ) or \(600 .\) g of lead (with a density of \(\left.11.34 \mathrm{g} / \mathrm{cm}^{3}\right) ?\)

The platinum-containing cancer drug cisplatin contains \(65.0 \%\) platinum. If you have \(1.53 \mathrm{g}\) of the compound, what mass of platinum (in grams) is contained in this sample?

The solder once used by plumbers to fasten copper pipes together consists of \(67 \%\) lead and \(33 \%\) tin. What is the mass of lead in a \(250-\mathrm{g}\) block of solder?

The anesthetic procaine hydrochloride is often used to deaden pain during dental surgery. The compound is packaged as a \(10 . \% \text { solution (by mass; } d=1.0 \mathrm{g} / \mathrm{mL})\) in water. If your dentist injects 0.50 mL of the solution, what mass of procaine hydrochloride (in milligrams) is injected?

A cube of aluminum (density \(=2.70 \mathrm{g} / \mathrm{cm}^{3}\) ) has a mass of 7.6 g. What must be the length of the cube's edge (in centimeters)? (See General Chemistry Now Screen 1.10 Tutorial \(2,\) Density.)

You have a 100.0 -mL graduated cylinder containing \(50.0 \mathrm{mL}\) of water. You drop a \(154-\mathrm{g}\) piece of brass \(\left(d=8.56 \mathrm{g} / \mathrm{cm}^{3}\right)\) into the water. How high does the water rise in the graduated cylinder? (a) A graduated cylinder with 50.0 ml of water. (b) A piece of brass is added to the cylinder.

You have a white crystalline solid, known to be one of the potassium compounds listed below. To determine which, you measure the solid's density. You measure out \(18.82 \mathrm{g}\) and transfer it to a graduated cylinder containing kerosene (in which salts will not dissolve). The level of liquid kerosene rises from \(8.5 \mathrm{mL}\) to \(15.3 \mathrm{mL}\). Calculate the density of the solid, and identify the compound from the following list. (a) \(\mathrm{KF}, d=2.48 \mathrm{g} / \mathrm{cm}^{3} \quad\) (c) \(\mathrm{KBr}, d=2.75 \mathrm{g} / \mathrm{cm}^{3}\) (b) \(\mathrm{KCl}, d=1.98 \mathrm{g} / \mathrm{cm}^{3} \quad\) (d) \(\mathrm{KI}, d=3.13 \mathrm{g} / \mathrm{cm}^{3}\)

A distant acquaintance has offered to sell you a necklace, said to be pure ( 24 -carat) gold, for \(\$ 300 .\) You have some doubts, however; perhaps it is gold plated. You decide to run a test. You have a graduated cylinder and a small balance. You partially fill the cylinder with water and immerse the necklace; the height of water rises from \(22.5 \mathrm{mL}\) to \(26.0 \mathrm{mL} .\) Then you determine the mass to be \(67 \mathrm{g} .\) You recall that the density of gold is \(19.3 \mathrm{g} / \mathrm{cm}^{3},\) and that no other element has a density near this value. (Silver has a density of \(\left.11.5 \mathrm{g} / \mathrm{cm}^{3} .\right)\) The price of gold on the open market is \(\$ 380\) per troy ounce ( 1 troy ounce \(=31.1 \mathrm{g}\) ). Is the necklace gold? Explain your conclusion. Is \(\$ 300\) a good price?

Small chips of iron are mixed with sand (see the photo). Is this a homogeneous or heterogeneous mixture? Suggest a way to separate the iron from the sand. (IMAGE CAN'T COPY)

The following photo shows copper balls, immersed in water, floating on top of mercury. What are the liquids and the solids in this photo? Which substance is most dense? Which is least dense? (IMAGE CAN'T COPY)

Carbon tetrachloride, \(\mathrm{CCl}_{4},\) a liquid compound, has a density of \(1.58 \mathrm{g} / \mathrm{cm}^{3} .\) If you place a piece of a plastic soda bottle \(\left(d=1.37 \mathrm{g} / \mathrm{cm}^{3}\right)\) and a piece of aluminum \((d=\) \(\left.2.70 \mathrm{g} / \mathrm{cm}^{3}\right)\) in liquid \(\mathrm{CCl}_{4},\) will the plastic and aluminum float or sink?

A You have a sample of a white crystalline substance from your kitchen. You know that it is either salt or sugar. Although you could decide by taste, suggest another property that you could use to determine the sample's identity. (Hint: You may use the World Wide Web or a handbook of chemistry in the library to find some pertinent information.)

Milk in a glass bottle was placed in the freezer compartment of a refrigerator overnight. By morning a column of frozen milk emerged from the bottle. Explain this observation.(IMAGE CAN'T COPY)

The element gallium has a melting point of \(29.8^{\circ} \mathrm{C} .\) If you held a sample of gallium in your hand, should it melt? Explain briefly. (IMAGE CAN'T COPY)

A The density of pure water is given at various temperatures. $$\begin{array}{ll} \hline T\left(^{\circ} \mathrm{C}\right) & d\left(\mathrm{g} / \mathrm{cm}^{3}\right) \\ \hline 4 & 0.99997 \\ 15 & 0.99913 \\ 25 & 0.99707 \\ 35 & 0.99406 \\ \hline \end{array}$$ Suppose your laboratory partner tells you that the density of water at \(20^{\circ} \mathrm{C}\) is \(0.99910 \mathrm{g} / \mathrm{cm}^{3} .\) Is this a reasonable number? Why or why not?

You can figure out whether a substance floats or sinks if you know its density and the density of the liquid. In which of the liquids listed below will high- density polyethylene (HDPE, a common plastic whose density is \(0.97 \mathrm{g} / \mathrm{mL}\) ) float? (HDPE does not dissolve in these liquids.) $$\begin{array}{lll} \hline \text { Substance } & \text { Density }\left(\mathrm{g} / \mathrm{cm}^{3}\right) & \text { Properties, Uses } \\ \hline \text { Ethylene glycol } & 1.1088 & \begin{array}{l} \text { Toxic; the major component } \\ \text { of automobile antifreeze } \end{array} \\ \text { Water } & 0.9997 & \\ \text { Ethanol } & 0.7893 & \begin{array}{l} \text { The alcohol in alcoholic } \\ \text { beverages } \end{array} \\ \text { Methanol } & 0.7914 & \begin{array}{l} \text { Toxic; gasoline additive to } \\ \text { prevent gas line freezing } \end{array} \\ \text { Acetic acid } & 1.0492 & \text { Component of vinegar } \\ \text { Glycerol } & 1.2613 & \begin{array}{l} \text { Solvent used in home care } \\ \text { products. } \end{array} \\ \hline \end{array}$$