1. INTRODUCTORY CHEMISTRY INTRODUCTORY CHEMISTRY Concepts & Connections Sixth Edition by Charles H. Corwin Chapter 4 1 © 2011 Pearson Education, Inc. Chapter 4 Matter and Energy by Christopher Hamaker

2. 2 Chapter 4 © 2011 Pearson Education, Inc. Matter Matter is any substance that has mass and occupies volume. Matter exists in one of three physical states: 1.Solid 2.Liquid 3.Gas

3. 3 Chapter 4 © 2011 Pearson Education, Inc. Gaseous State In a gas, the particles of matter are far apart and uniformly distributed throughout the container. Gases have an indefinite shape and assume the shape of their container. Gases can be compressed and have an indefinite volume. Gases have the most energy of the three states of matter.

4. 4 Chapter 4 © 2011 Pearson Education, Inc. Liquid State In a liquid, the particles of matter are loosely packed and are free to move past one another. Liquids have an indefinite shape and assume the shape of their container. Liquids cannot be compressed and have a definite volume. Liquids have less energy than gases, but more energy than solids.

5. 5 Chapter 4 © 2011 Pearson Education, Inc. Solid State In a solid, the particles of matter are tightly packed together. Solids have a definite, fixed shape. Solids cannot be compressed and have a definite volume. Solids have the least energy of the three states of matter.

6. 6 Chapter 4 © 2011 Pearson Education, Inc. Physical States of Matter

7. 7 Chapter 4 © 2011 Pearson Education, Inc. Changes in Physical States Most substances can exist as either a solid, a liquid, or a gas. Water exists as a solid below 0 °C; as a liquid between 0 °C and 100 °C; and as a gas above 100 °C. A substance can change physical states as the temperature changes.

8. 8 Chapter 4 © 2011 Pearson Education, Inc. Solid ↔ Liquid Phase Changes When a solid changes to a liquid, the phase change is called melting. A substance melts as the temperature increases. When a liquid changes to a solid, the phase change is called freezing. A substance freezes as the temperature decreases.

9. 9 Chapter 4 © 2011 Pearson Education, Inc. Liquid ↔ Gas Phase Changes When a liquid changes to a gas, the phase change is called vaporization. A substance vaporizes as the temperature increases. When a gas changes to a liquid, the phase change is called condensation. A substance condenses as the temperature decreases.

10. 10 Chapter 4 © 2011 Pearson Education, Inc. Solid ↔ Gas Phase Changes When a solid changes directly to a gas, the phase change is called sublimation. A substance sublimes as the temperature increases. When a gas changes directly to a solid, the phase change is called deposition. A substance undergoes deposition as the temperature decreases.

11. 11 Chapter 4 © 2011 Pearson Education, Inc. Summary of State Changes

12. 12 Chapter 4 © 2011 Pearson Education, Inc. Classifications of Matter Matter can be divided into two classes: 1.Mixtures 2.Pure substances Mixtures are composed of more than one substance and can be physically separated into its component substances. Pure substances are composed of only one substance and cannot be physically separated.

13. 13 Chapter 4 © 2011 Pearson Education, Inc. Mixtures There are two types of mixtures: 1. Homogeneous mixtures 2. Heterogeneous mixtures Homogeneous mixtures have uniform properties throughout. –Salt water is a homogeneous mixture. Heterogeneous mixtures do not have uniform properties throughout. –Sand and water is a heterogeneous mixture.

14. 14 Chapter 4 © 2011 Pearson Education, Inc. Pure Substances There are two types of pure substances: 1.Compounds 2.Elements Compounds can be chemically separated into individual elements. –Water is a compound that can be separated into hydrogen and oxygen. An element cannot be broken down further by chemical reactions.

15. 15 Chapter 4 © 2011 Pearson Education, Inc. Matter Summary

16. 16 Chapter 4 © 2011 Pearson Education, Inc. Occurrence of the Elements There are over 100 elements that occur in nature; 81 of those elements are stable. Only 10 elements account for 95% of the mass of Earth’s crust:

17. 17 Chapter 4 © 2011 Pearson Education, Inc. Elements in the Human Body Oxygen is the most common element in Earth’s crust and in the human body. While silicon is the second most abundant element in Earth’s crust, carbon is the second most abundant in the body.

18. 18 Chapter 4 © 2011 Pearson Education, Inc. Names of the Elements Each element has a unique name. Names have several origins: –Hydrogen is derived from Greek. –Carbon is derived from Latin. –Scandium is named for Scandinavia. –Nobelium is named for Alfred Nobel. –Yttrium is named for the town of Ytterby, Sweden.

19. 19 Chapter 4 © 2011 Pearson Education, Inc. Element Symbols Each element is abbreviated using a chemical symbol. The symbols are one or two letters long. Most of the time, the symbol is derived from the name of the element. –C is the symbol for carbon. –Cd is the symbol for cadmium. When a symbol has two letters, the first is capitalized and the second is lowercase.

20. 20 Chapter 4 © 2011 Pearson Education, Inc. Other Element Symbols For some elements, the chemical symbol is derived from the original Latin name. Gold – AuSodium – Na Silver – AgAntimony – Sb Copper – CuTin – Sn Mercury – HgIron – Fe Potassium – KTungsten – W

21. 21 Chapter 4 © 2011 Pearson Education, Inc. Types of Elements Elements can be divided into three classes: 1.Metals 2.Nonmetals 3.Semimetals or metalloids Semimetals have properties midway between those of metals and nonmetals.

22. 22 Chapter 4 © 2011 Pearson Education, Inc. Metal Properties Metals are typically solids with high melting points and high densities and have a bright, metallic luster. Metals are good conductors of heat and electricity. Metals can be hammered into thin sheets and are said to be malleable. Metals can be drawn into fine wires and are said to be ductile.

23. 23 Chapter 4 © 2011 Pearson Education, Inc. Nonmetal Properties Nonmetals typically have low melting points and low densities and have a dull appearance. Nonmetals are poor conductors of heat and electricity. Nonmetals are not malleable or ductile and crush into a powder when hammered. Eleven nonmetals occur naturally in the gaseous state.

24. 24 Chapter 4 © 2011 Pearson Education, Inc. Summary of Properties

25. 25 Chapter 4 © 2011 Pearson Education, Inc. Periodic Table of the Elements Each element is assigned a number to identify it. It is called the atomic number. Hydrogen’s atomic number is 1; helium is 2; up to uranium, which is 92. The elements are arranged by atomic number on the periodic table.

26. 26 Chapter 4 © 2011 Pearson Education, Inc. The Periodic Table

27. 27 Chapter 4 © 2011 Pearson Education, Inc. Metals, Nonmetals, and Semimetals Metals are on the left side of the periodic table, nonmetals are on the right side, and the semimetals are in between.

28. 28 Chapter 4 © 2011 Pearson Education, Inc. Physical States of the Elements Shown are the physical states of the elements at 25 °C on the periodic table.

29. 29 Chapter 4 © 2011 Pearson Education, Inc. Law of Definite Composition The law of definite composition states that “Compounds always contain the same elements in a constant proportion by mass.” Water is always 11.19% hydrogen and 88.81% oxygen by mass, no matter what its source. Ethanol is always 13.13% hydrogen, 52.14% carbon, and 34.73% oxygen by mass.

30. 30 Chapter 4 © 2011 Pearson Education, Inc. Chemical Formulas A particle composed of two or more nonmetal atoms is a molecule. A chemical formula is an expression of the number of and types of atoms in a molecule. The chemical formula of sulfuric acid is H 2 SO 4.

31. 31 Chapter 4 © 2011 Pearson Education, Inc. Writing Chemical Formulas The number of each type of atom in a molecule is indicated with a subscript in a chemical formula. If there is only one atom of a certain type, no “1” is used. A molecule of the vitamin niacin has six carbon atoms, six hydrogen atoms, two nitrogen atoms, and one oxygen atom. What is the chemical formula? C6H6N2OC6H6N2O

32. 32 Chapter 4 © 2011 Pearson Education, Inc. Interpreting Chemical Formulas Some chemical formulas use parentheses to clarify atomic composition. Ethylene glycol, a component of some antifreezes, has a chemical formula of C 2 H 4 (OH) 2. It contains two carbon atoms, four hydrogen atoms, and two OH units, giving a total of six hydrogen atoms and two oxygen atoms. How many total atoms are in ethylene glycol? Ethylene glycol has a total of ten atoms.

33. 33 Chapter 4 © 2011 Pearson Education, Inc. Physical and Chemical Properties A physical property is a characteristic of a pure substance that we can observe without changing its composition. Physical properties include appearance, melting and boiling points, density, conductivity, and physical state. A chemical property describes the chemical reactions of a pure substance.

34. 34 Chapter 4 © 2011 Pearson Education, Inc. Chemical Properties Sodium metal (Na) reacts with chlorine gas (Cl 2 ) to produce sodium chloride (NaCl).

35. 35 Chapter 4 © 2011 Pearson Education, Inc. Physical and Chemical Change A physical change is a change where the chemical composition of the substance is not changed. These include changes in physical state or shape of a pure substance. A chemical change is a chemical reaction. The composition of the substances changes during a chemical change.

36. 36 Chapter 4 © 2011 Pearson Education, Inc. Evidence for Chemical Changes Gas release (bubbles) Light or release of heat energy Formation of a precipitate A permanent color change

37. 37 Chapter 4 © 2011 Pearson Education, Inc. Conservation of Mass Antoine Lavoisier found that the mass of substances before a chemical change was always equal to the mass of substances after a chemical change. This is the law of conservation of mass. Matter is neither created nor destroyed in physical or chemical processes.

38. 38 Chapter 4 © 2011 Pearson Education, Inc. Conservation of Mass Example If 1.0 gram of hydrogen combines with 8.0 grams of oxygen, 9.0 grams of water is produced. Consequently, 3.0 grams of hydrogen combine with 24.0 grams of oxygen to produce 27.0 grams of water. If 50.0 grams of water decompose to produce 45.0 grams of oxygen, how many grams of hydrogen are produced? 50.0 g water – 45.0 g oxygen = 5.0 g hydrogen

39. 39 Chapter 4 © 2011 Pearson Education, Inc. Potential and Kinetic Energy Potential energy, PE, is stored energy; it results from position or composition. Kinetic energy, KE, is the energy matter has as a result of motion. Energy can be converted between the two types. A boulder at the top of the hill has potential energy; if you push it down the hill, the potential energy is converted to kinetic energy.

40. 40 Chapter 4 © 2011 Pearson Education, Inc. Energy

41. 41 Chapter 4 © 2011 Pearson Education, Inc. KE, Temperature, and Physical State All substances have kinetic energy regardless of their physical state. Solids have the lowest kinetic energy, and gases have the greatest kinetic energy. As you increase the temperature of a substance, its kinetic energy increases.

42. 42 Chapter 4 © 2011 Pearson Education, Inc. Law of Conservation of Energy Just like matter, energy cannot be created or destroyed, but it can be converted from one form to another. This is the law of conservation of energy. There are six forms of energy: 1.Heat 2.Light 3.Electrical 4.Mechanical 5.Chemical 6.Nuclear

43. 43 Chapter 4 © 2011 Pearson Education, Inc. Energy and Chemical Changes In a chemical change, energy is transformed from one form to another. For example:

44. 44 Chapter 4 © 2011 Pearson Education, Inc. Law of Conservation of Mass and Energy Mass and energy are related by Einstein’s theory of relativity, E = mc 2. Mass and energy can be interchanged. The law of conservation of mass and energy states that the total mass and energy of the universe is constant.

45. 45 Chapter 4 © 2011 Pearson Education, Inc. Chemistry Connection: Al Recycling Although aluminum is very abundant in Earth’s crust, it is difficult to purify it from its ore. The energy from 8 tons of coal is required to produce 1 ton of aluminum metal from its ore. However, it only takes the energy from 0.4 tons of coal to produce 1 ton of aluminum from recycled scrap.

46. 46 Chapter 4 © 2011 Pearson Education, Inc. Chapter Summary Matter exists in three physical states: 1.Solid 2.Liquid 3.Gas Substances can be converted between the three states. Substances can be mixtures or pure substances.

47. 47 Chapter 4 © 2011 Pearson Education, Inc. Chapter Summary, Continued Pure substances can be either compound or elements. The elements are arranged in the periodic table. Each element has a name and a one- or two-letter symbol. Elements are classified as either metals, nonmetals, or semimetals.

48. 48 Chapter 4 © 2011 Pearson Education, Inc. Chapter Summary, Continued A physical change is a change in physical state or shape. A chemical change is a change in the chemical composition of a substance. Both mass and energy are conserved in chemical and physical changes.