# Chemistry

48 Chapter 1 Matter and Energy

1.15 Express the answers to the following calculations with the proper number of significant figures and with the correct units.

(a) 10.00 L

(20.90 kg − 12.90 kg)

(b) (3.0 cm)3 45.82 g

(0.859 cm)3 0.64 g− ÷ 2

(Assume that the 2 with no units is an exact number.) (c) (0.35 m × 0.55 m) + 25.2 m2

1.16 Express the answers to the following calculations with the proper number of significant figures and with the correct units. (a) (0.25 m/s) × (45.77 s) + 5.0 m

(b) (62.9 gal − 58.9 gal)

2.523 lb

(c) (9.0 cm × 15.1 cm × 10.5 cm) + 75.7 cm3

1.17 Round each of the following numbers to three significant figures. (a) 1.2126 (d) 42.186 (b) 0.2045 (e) 0.007101 (c) 1.8351

1.18 Round each of the following numbers to three significant figures. (a) 0.020450 (d) 16.225 (b) 1.3602 × 104 (e) 1.0001 (c) 13.475

1.19 Carry out the following conversions. Report your answers to the correct number of significant figures. (a) 36 mm to m (g) 168 lb to g (b) 357 kg to g (h) 914 qt to L (c) 76.50 mL to L (i) 44.5 cm to in (d) 0.0084670 m to cm (j) 236.504 g to lb (e) 597 nm to m (k) 2.0 L to qt (f) 36.5 in to cm

1.20 Carry out the following conversions. Report your answers to the correct number of significant figures. (a) 75.5 km to m (g) 25.6 lb to g (b) 25.7 g to mg (h) 4.005 qt to L (c) 0.516 L to dL (i) 934 cm to in (d) 5.2 cm to m (j) 155 g to lb (e) 0.000000450 m to nm (k) 22.4 L to qt (f) 12 in to cm

1.21 Carry out the following conversions. Report your answers to the correct number of significant figures. (a) 947 m to mi (g) 689 lb to kg (b) 6.74 kg to lb (h) 0.5 qt to mL (c) 250.4 mL to gal (i) 125 cm to ft (d) 2.30 dL to mL (j) 542 mg to lb (e) 0.000450 cm to nm (k) 25 nL to gal (f) 37.5 in to m

1.22 Carry out the following conversions. Report your answers to the correct number of significant figures. (a) 32 cm to ft (g) 2.7 lb to kg (b) 0.579 kg to lb (h) 8.320 qt to mL (c) 22.70 μL to qt (i) 375 km to ft (d) 9212 mm to km (j) 62 g to oz (e) 465 nm to mm (k) 752 mL to gal (f) 4 ft to cm

1.23 Carry out the following conversions. Report your answers to the correct number of significant figures. (a) 375 m/s to ft/min (b) 24.5 cm3 to in3 (c) 19.3 g/mL to lb/in3

1.24 Carry out the following conversions. Report your answers to the correct number of significant figures. (a) 27 ft/s to cm/min (b) 2764 ft3 to m3 (c) 0.927 g/mL to lb/gal

Matter and Its Classification 1.25 How would you classify the following items observed by

Bill and Anna? (a) water in a fountain containing dissolved dye (b) a copper pipe (c) the contents of a balloon after blowing it up by mouth (d) a slice of pizza

1.26 How would you classify the following items observed by Bill and Anna? (a) sand in a volleyball court (b) a baseball bat made entirely of aluminum (c) the contents of a balloon filled from a helium tank (d) a glass filled with a soft drink

1.27 Which of the following are examples of matter? (a) sunlight (b) gasoline (c) automobile exhaust (d) oxygen gas (e) iron pipe

1.28 Which of the following are not examples of matter? (a) light from a fluorescent bulb (b) sand (c) wheelbarrow rolling down a ramp (d) helium balloons (e) heat from a welding torch

1.29 How are elements distinguished from compounds? 1.30 How are homogeneous mixtures distinguished from

heterogeneous mixtures? 1.31 List characteristics of metals. 1.32 List characteristics of nonmetals. 1.33 Name the following elements.

(a) Ti (b) Ta (c) Th (d) Tc (e) Tl 1.34 Name the following elements.

(a) C (e) Cu (b) Ca (f) Cl (c) Cr (g) Cs (d) Co

1.35 Name the following elements. (a) B (b) Ba (c) Be (d) Br (e) Bi

1.36 Name the following elements. (a) S (b) Si (c) Se (d) Sr (e) Sn

1.37 Name the following elements. (a) N (c) Mn (e) Al (b) Fe (d) Mg (f) Cl

1.38 Name the following elements. (a) Be (c) Ni (e) Ti (b) Rb (d) Sc (f) Ne

Questions and Problems 49

1.49 This image is a representation for a compound containing nitrogen and oxygen. Write the formula for this compound.

N O

1.50 This image represents a compound containing phosphorus and chlorine. Write the formula for this compound.

P Cl

1.51 Which of the images represents a mixture of an element and a compound?

A B C D

A B C D E

1.52 Which of the images in Question 1.51 represents a pure substance that is a compound?

1.53 Classify each of the following as an element or a compound. (a) O2 (c) P4 (e) NaCl (b) Fe2O3 (d) He (f) H2O

1.54 Classify each of the following as an element or a compound. (a) hydrogen gas (d) nitrogen dioxide (b) water (e) aluminum chloride (c) salt (f ) neon

1.55 Under normal conditions, mercury is a liquid. Draw molecular-level pictures of what mercury atoms might look like in the liquid and solid states.

1.56 Under normal conditions, bromine is a liquid. Draw molecular-level pictures of what bromine, Br2, might look like in the liquid and gaseous states.

1.57 What type of matter expands to fill its container and can be compressed to a smaller volume?

1.58 What type of matter is composed of particles that do not move past one another?

1.59 Identify the physical state of each of the following elements from their symbols. (a) Cl2(g) (b) Hg(l) (c) C(s)

1.39 What are the symbols for the following elements? (a) iron (d) gold (b) lead (e) antimony (c) silver

1.40 What are the symbols for the following elements? (a) copper (d) sodium (b) mercury (e) tungsten (c) tin

1.41 A chemical novice used the symbol Ir to represent iron. Is this an acceptable symbol for the element? If not, what is the correct symbol for iron?

1.42 A chemical novice used the symbol SI to represent silicon. Is this an acceptable symbol for the element? If not, what is the correct symbol?

1.43 The symbol NO was used by a student to represent nobelium, an unstable, synthetic element. Is this an acceptable symbol for the element? If not, what is the correct symbol?

1.44 A student used the symbol CO to represent cobalt, an element found in vitamin B12. Is this an acceptable symbol for the element? If not, what is the correct symbol?

1.45 Classify each of the following as a pure substance, a homogeneous mixture (solution), or a heterogeneous mixture: hamburger, salt, soft drink, and ketchup.

1.46 Classify each of the following as a pure substance, a homogeneous mixture (solution), or a heterogeneous mixture: sand, boardwalk, ocean, and roller coaster.

1.47 Elemental hydrogen normally exists as two hydrogen atoms bound together. Write the formula for this molecule, and draw a picture to represent how it might look on a molecular level.

1.48 Elemental chlorine normally exists as two chlorine atoms bound together. Write the formula for this molecule, and draw a picture to represent how it might look on a molecular level.

50 Chapter 1 Matter and Energy

1.71 If you drank 1.2 L of a sports drink, what volume did you consume in the following units? (a) milliliters (b) cubic centimeters (c) cubic meters

1.72 If the volume of helium in a balloon is 145 cm3, what is its volume in the following units? (a) milliliters (b) liters (c) cubic meters

1.73 If the length, width, and height of a box are 8.0 cm, 5.0 cm, and 4.0 cm, respectively, what is the volume of the box in units of milliliters and liters?

1.74 If a cubic box (all sides the same length) has a volume of 1.0 L, what is the length of each side of the box?

1.75 A slice of cheese has a mass of 28 g and a volume of 21 cm3. What is the density of the cheese in units of g/cm3 and g/mL?

1.76 Two stones resembling diamonds are suspected of being fakes. To determine if the stones might be real, the mass and volume of each were measured. Both stones have the same volume, 0.15 cm3. However, stone A has a mass of 0.52 g and stone B has a mass of 0.42 g. If diamond has a density of 3.5 g/cm3, could the stones be real diamonds? Explain.

1.77 If the density of a sugar solution is 1.30 g/mL, what volume of this solution has a mass of 50.0 g?

1.78 The density of a certain type of plastic is 0.75 g/cm3. If a sheet of this plastic is 10.0 m long, 1.0 m wide, and 1 cm thick, what is its mass?

1.79 Why do liquids have greater densities than gases? 1.80 When a balloon filled with air is heated, the balloon

increases in volume. Does the density of the air in the balloon increase, decrease, or remain the same?

1.81 A piece of plastic sinks in oil but floats in water. Place these three substances in order from lowest density to greatest density.

1.82 What special molecular-level feature of ice explains why ice floats in water?

Ice Liquid water

1.83 Acetone, a component of some types of fingernail polish remover, has a boiling point of 56°C. What is its boiling point in units of kelvin?

1.84 The boiling point of liquid nitrogen is 77 K. What is its boiling point in units of degrees Celsius?

1.85 What is the difference in temperature between the boiling point of water and the freezing point of water in each of the following temperature scales? (a) Celsius scale (b) Kelvin scale (c) Fahrenheit scale

1.60 Identify the physical state of each of the following compounds from their symbols. (a) NaCl(s) (b) CH3OH(l) (c) CO2(g)

1.61 What physical state is represented in this diagram?

1.62 Draw a picture of the gaseous state of the substance shown in Question 1.61.

1.63 How might you symbolically represent a homogeneous mixture of oxygen, O2, and water?

1.64 Why does the symbol H2O(aq) make no sense?

Physical and Chemical Changes and Properties of Matter 1.65 At the beginning of the chapter, Anna and Bill made

many observations about what they saw. Some of their observations included color, texture, and shininess. Are these physical or chemical properties?

1.66 At the beginning of the chapter, you were asked to classify processes like a truck running on gas or welding pieces of metal. After reading the chapter, would you classify these processes as physical or chemical changes?

1.67 A slice of Swiss cheese contains 45 mg of sodium. (a) What is this mass in units of grams? (b) What is this mass in units of ounces (oz)?

(16 oz = 453.6 g) (c) What is this mass in pounds (lb)?

(1 lb = 453.6 g) 1.68 A package of Swiss cheese has a mass of 0.340 kg.

(a) What is this mass in grams? (b) What is this mass in ounces (oz)?

(16 oz = 453.6 g) (c) What is this mass in pounds (lb)?

(1 lb = 453.6 g) 1.69 A grain of salt has a mass of about 1.0 × 10−4 g. What is

its mass in the following units? (a) milligrams (b) micrograms (c) kilograms

1.70 If a dog has a mass of 15.2 kg, what is its mass in the following units? (a) grams (b) milligrams (c) micrograms

Questions and Problems 51

1.96 Do the changes shown in this diagram represent a physical or chemical change?

AfterBefore

1.97 Draw a picture that shows CH4 (shown in the “After” image in Question 1.95) condensing from a gas to a liquid. Does this picture represent a physical or a chemical change?

1.98 Draw a picture that shows water boiling. Does this picture represent a physical or chemical change?

1.99 The image shows what happens when iodine, I2, is placed in the bottom of a beaker and heated. Is this a physical or chemical change? (Note that the photo shows an inner flask containing ice.)

©Charles D. Winters/Science Source 1.100 The picture shows natural gas (CH4) burning. In the

process, carbon dioxide and water form. Is this a physical change or a chemical change?

Energy and Energy Changes 1.101 Anna and Bill saw a construction worker welding pipe.

Classify the forms of energy they were observing. 1.102 Bill and Anna watched students playing volleyball in

the sunshine. Classify the forms of energy they were observing.

1.86 If the temperature of a cup of coffee decreases from 60.0°C to 25.0°C, what is the decrease in temperature in units of degrees Celsius and kelvin?

1.87 Does the boiling point of a substance depend on how much of this substance you have?

1.88 Does the melting point of a substance depend on how much of this substance you have?

1.89 Identify each of the following as a physical property or a chemical property. (a) mass (b) density (c) flammability (d) resistance to corrosion (e) melting point (f) reactivity with water

1.90 Identify each of the following as a physical property or a chemical property. (a) boiling point (b) reactivity with oxygen (c) resistance to forming compounds with other

elements (d) volume

1.91 Identify each of the following as a physical change or a chemical change. (a) boiling acetone (b) dissolving oxygen gas in water (c) combining hydrogen and oxygen gas to make water (d) burning gasoline (e) screening rocks from sand (f) the conversion of ozone to oxygen, 2O3(g) ⟶ 3O2(g)

1.92 Identify each of the following as a physical change or a chemical change. (a) condensation of ethanol (b) combining zinc and oxygen to make the compound

zinc oxide (c) dissolving sugar in water (d) burning a piece of paper (e) combining sodium metal with water, producing

sodium hydroxide and hydrogen gas (f) filtering algae from water

1.93 Write a symbolic representation and a molecular-level representation for the change that occurs during the condensation of chlorine, Cl2.

1.94 Write a symbolic representation and a molecular-level representation for the process of freezing oxygen, O2.

1.95 Do the changes shown in this diagram represent a physical or chemical change?

Before After

Questions and Problems 53

1.134 The densities of antifreeze, corn oil, dish detergent, maple syrup, shampoo, and water in g/mL are 1.13, 0.93, 1.03, 1.32, 1.01, and 1.00, respectively. Which layer is which substance in the figure?

1.135 The lowest possible temperature is the temperature at which a substance would have no kinetic energy (no motion). What is the lowest possible temperature in each of the following temperature units? (a) Kelvin scale (b) Celsius scale (c) Fahrenheit scale

1.136 Classify the substance in the molecular-level image as: (a) an element, compound, or mixture (b) atoms or molecules

1.137 Classify each of the following as a symbolic representation for a pure element, pure compound, or mixture. (a) NaNO3(s) (b) N2(g) (c) NaCl(aq)

1.138 Titanium is a strong metal with a low density that is shiny with a white-metallic color. It is relatively resistant to corrosion by acids and chlorine and resists tarnishing by air by forming a protective oxide layer. It is described as a nontoxic, inert biomaterial, which means that it does not interact unfavorably with human tissues and fluids. Identify all the chemical and physical properties of titanium in this description.

Additional Questions 1.122 Rank the following measurements in order from smallest

to largest: 1.0 × 10−4 m, 2.0 × 10−5 m, 3.0 × 10−6 km, 4.0 × 102 mm, 0.0 m, 1.0 m.

1.123 The density of air in a balloon is less at high altitudes than at low altitudes. Explain this difference.

1.124 If the temperature in a room increases from 20.0°C to 30.0°C, what is the temperature change in units of kelvin?

1.125 If you have a sample of zinc and a sample of copper, and both have the same mass, which has the greatest volume?

1.126 Give the symbols for potassium and phosphorus. 1.127 Give the symbols for the following noble gas elements:

(a) helium (b) neon (c) argon (d) krypton (e) xenon (f) radon

1.128 The red blood cell (RBC) count for a normal female is about 5 million RBCs per μL (1 μL = 1 mm3). How many red blood cells are in a gallon of normal female blood?

1.129 Recycling facilities around the world use a variety of techniques to separate different types of recyclable waste. Wet separation is a method that involves processing certain kinds of waste (for example, glass, sand, and metal) based on their densities relative to water. Is this type of separation based on the physical or chemical properties of the recyclable waste?

1.130 These samples of metals have the same mass. Which has the greater density?