1. Matter of Change how matter changes .pptx

The Changes of Matter

1. Review ion New compound chemical bond covalent bond molecule ionic bond metallic bond chemical reaction solution acid base Copyright © McGraw-Hill Education Vocabulary Combining Matter

2. Chapter 2 Section 2 & 3 Earth Science

3. What are the different types of chemical bonds that unite atoms to form compounds?

4. What is the difference between What mixtures and solutions?

5. Combining Matter Copyright © McGraw-Hill Education Compounds A compound is a substance that is composed of atoms of two or more different elements that are chemically combined. Compounds have different properties from the elements of which they are composed.

6. Copyright © McGraw-Hill Education Combining Matter Compounds Chemical formulas Compounds are represented by chemical formulas that include the symbol for each element followed by a subscript number showing the number of atoms of that element in the compound.

7. Copyright © McGraw-Hill Education Combining Matter Covalent Bonds A state of stability is achieved by some elements by forming chemical bonds. A chemical bond is the force that holds together the elements in a compound. The attraction of two atoms for a shared pair of electrons that holds the atoms together is called a covalent bond .

8. Copyright © McGraw-Hill Education Combining Matter Covalent Bonds In this example, the nucleus of each atom has one proton with a positive charge. The two positively charged protons attract the two negatively charged electrons.

9. Copyright © McGraw-Hill Education Combining Matter Covalent Bonds Molecules A molecule is composed of two or more atoms held together by covalent bonds. A compound comprised of molecules is called a molecular compound.

10. Copyright © McGraw-Hill Education Combining Matter Covalent Bonds Polar molecules Molecules held together by covalent bonds may not share electrons equally, resulting in the electrons spending more time near one atom than another. This unequal sharing results in polar molecules.

11. Copyright © McGraw-Hill Education Combining Matter Covalent Bonds Polar molecules A polar molecule has a slightly positive end and a slightly negative end.

12. Copyright © McGraw-Hill Education Combining Matter Ionic Bonds An ionic bond is the attractive force between two ions of opposite charge. Compounds formed by ionic bonds are called ionic compounds.

13. Copyright © McGraw-Hill Education Combining Matter Ionic Bonds A sodium atom tends to lose a single valence electron, and a chlorine atom tends to gain a single valence electron. An ionic bond is formed by the attraction between oppositely charged ions.

14. Copyright © McGraw-Hill Education Metallic Bonding In a metallic bond , the positive ions of the metal are held together by the attraction to the negative electrons moving among them. Combining Matter

15. Copyright © McGraw-Hill Education Metallic Bonding Metallic bonds allow metals to conduct electricity because some of the electrons move freely throughout the entire metal. Combining Matter When a force is applied to a metal, some of the electrons are pushed aside. This allows the metal ions to move past each other, thus deforming or changing the shape of the metal.

16. Copyright © McGraw-Hill Education Combining Matter Chemical Reactions The change of one or more compounds into other compounds is called a chemical reaction . Chemical reactions are described by chemical equations.

17. Copyright © McGraw-Hill Education Combining Matter Chemical Reactions Example Water is formed by the chemical reaction between hydrogen gas (H2) and oxygen gas (O 2 ).

18. Copyright © McGraw-Hill Education Combining Matter Chemical Reactions When you write a chemical equation, you must balance the equation by showing an equal number of atoms for each element on each side of the equation. Therefore, the same amount of matter is present both before and after the reaction.

19. Copyright © McGraw-Hill Education Combining Matter Mixtures and Solutions A mixture is a combination of two or more components that retain their identities. When a mixture’s components are easily recognizable, it is called a heterogeneous mixture. In a homogeneous mixture, also called a solution , the component particles cannot be distinguished, even though they still retain their original properties. A solution can be liquid, gaseous, or solid.

20. Copyright © McGraw-Hill Education Combining Matter Bases When a solution produces hydroxide ions (OH–) in water, the solution is called a base . Mixtures and Solutions Acids An acid is a solution containing a substance that produces hydrogen ions (H+) in water. The pH scale is based on the amount of hydrogen ions in a solution.

21. States of Matter Copyright © McGraw-Hill Education Solids Solids are substances with densely packed particles, which can be ions, atoms, or molecules. Most solids are crystalline structures because the particles of a solid are arranged in regular geometric patterns, giving solids definite shape and volume. Glass is a solid that consists of densely packed atoms arranged randomly.

22. Copyright © McGraw-Hill Education States of Matter Liquids An increase in temperature increases the thermal vibrations of atoms in a solid. When thermal vibrations become vigorous enough to break the forces holding the solid together, the particles can slide past each other, and the substance becomes liquid. Liquids take the shape of the container they are placed in, but they do have a definite volume.

23. Copyright © McGraw-Hill Education States of Matter Gases Some vibrating particles can gain sufficient thermal energy to escape a liquid. This process of change from a liquid to a gas at temperatures below the boiling point is called evaporation . Gases, like liquids, have no definite shape. Gases also have no definite volume unless they are restrained by a container or a force such as gravity.

24. Copyright © McGraw-Hill Education States of Matter Plasma At extreme temperatures, the collisions between particles in matter are so violent that electrons are knocked away from atoms, resulting in hot, highly ionized, electrically conducting gases called plasmas .

25. Copyright © McGraw-Hill Education States of Matter Liquids When liquids are cooled, they solidify at that same temperature and release thermal energy. The temperature at which liquids solidify is called the freezing point . When a liquid is heated to the boiling point and absorbs enough thermal energy, vaporization occurs, and the liquid becomes a gas. Solids Solids melt when they absorb enough thermal energy to cause their orderly internal crystalline arrangement to break down. This happens at the melting point .

26. Copyright © McGraw-Hill Education States of Matter Gas When a gas is cooled to the boiling point, it releases thermal energy and becomes a liquid in a process called condensation . The slow change of state from a solid to a gas without an intermediate liquid state is called sublimation .

27. Copyright © McGraw-Hill Education States of Matter Conservation of Energy The fundamental fact that matter cannot be created or destroyed is called the law of conservation of matter. Like matter, energy cannot be created or destroyed, but it can be changed from one form to another. This law, called the conservation of energy, is also known as the first law of thermodynamics.

28. Copyright © McGraw-Hill Education Review Essential Questions What are the different types of chemical bonds that unite atoms to form compounds? How is the nature of chemical bonds that hold compounds together related to the physical structures of compounds? What are the different types of mixtures and solutions? Vocabulary compound chemical bond covalent bond molecule Combining Matter ionic bond metallic bond chemical reaction solution acid base