Unit 2 Lesson 3 Pure Substances and Mixtures Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 2 Lesson 3 Pure Substances and Mixtures Indiana Standards 8.1.1 Explain that all matter is composed of particular arrangements of atoms of approximately one hundred elements.. 8.1.5 Explain that atoms join together to form molecules and compounds and illustrate with diagrams the relationship between atoms and compounds and/or molecules. Copyright © Houghton Mifflin Harcourt Publishing Company 2

Unit 2 Lesson 3 Pure Substances and Mixtures Indiana Standards 8.1.6 Explain that elements and compounds have characteristic properties such as density, boiling points and melting points, that remain unchanged regardless of the sample size. Copyright © Houghton Mifflin Harcourt Publishing Company 3

A Great Combination How can matter be classified? Unit 2 Lesson 3 Pure Substances and Mixtures A Great Combination How can matter be classified? Matter is made up of basic “ingredients” known as atoms. An atom is the smallest unit of an element that maintains the properties of that element. Substances are classified as elements, compounds, and mixtures. Copyright © Houghton Mifflin Harcourt Publishing Company 4

Bell Work 1/20 How is matter classified?

How can matter be classified? Unit 2 Lesson 3 Pure Substances and Mixtures How can matter be classified? An element is made of only one kind of atom. A compound is made up of different kinds of atoms chemically combined. A mixture contains a variety of elements and compounds that are not chemically combined. Copyright © Houghton Mifflin Harcourt Publishing Company 6

Which type of substance is always made up of a single type of atom? Molecule Compound Element

What do elements, compounds, and mixtures have in common? They are all made up of pure substances They are all made up of atoms They can all be broken down by physical changes

How can matter be classified? Unit 2 Lesson 3 Pure Substances and Mixtures How can matter be classified? Is water an element, compound, or mixture? Quiz ? Copyright © Houghton Mifflin Harcourt Publishing Company 9

Pure Genius What are pure substances? Unit 2 Lesson 3 Pure Substances and Mixtures Pure Genius What are pure substances? A pure substance is a substance with definite physical and chemical properties: density, boiling point, and melting point . Pure substances are made up of just one type of particle. Elements and compounds are pure substances. Copyright © Houghton Mifflin Harcourt Publishing Company 10

What are pure substances? Unit 2 Lesson 3 Pure Substances and Mixtures What are pure substances? Physical changes such as melting, freezing, cutting, or smashing do not change the identity of pure substances. When a pure substance undergoes a chemical change, it is no longer that same substance. Copyright © Houghton Mifflin Harcourt Publishing Company 11

Classified Information Unit 2 Lesson 3 Pure Substances and Mixtures Classified Information How can elements be classified? Elements are classified as metals, nonmetals, or metalloids. Classifying elements helps scientists predict the properties of elements. The periodic table is a tool used to classify and identify elements that have similar properties. Copyright © Houghton Mifflin Harcourt Publishing Company 12

How can compounds be classified? Unit 2 Lesson 3 Pure Substances and Mixtures How can compounds be classified? Compounds can be classified as acidic, basic, or neutral by measuring pH. Pure water has a pH of 7. Acids have a pH below 7. Bases have a pH above 7. Blue litmus paper turns red in the presence of an acid. Red litmus paper turns blue in the presence of a base. Copyright © Houghton Mifflin Harcourt Publishing Company 13

How can compounds be classified? Unit 2 Lesson 3 Pure Substances and Mixtures How can compounds be classified? Compounds can be organic or inorganic. Organic compounds are those that contain carbon and hydrogen. Organic compounds made by living things are called biochemicals. Carbohydrates, lipids, proteins, and nucleic acids are biochemical compounds. Copyright © Houghton Mifflin Harcourt Publishing Company 14

Mix and Match What are mixtures? Unit 2 Lesson 3 Pure Substances and Mixtures Mix and Match What are mixtures? A mixture is a combination of two or more substances that are combined physically but not chemically. Mixtures are not pure substances and do not have definite properties. Copyright © Houghton Mifflin Harcourt Publishing Company 15

Unit 2 Lesson 3 Pure Substances and Mixtures What are mixtures? Substances within a mixture keep their identities and individual properties. Mixtures can be separated by physical changes, although some mixtures are difficult to separate. Magnets, centrifuges, filters, and other materials can be used to separate mixtures. Copyright © Houghton Mifflin Harcourt Publishing Company 16

Simple Solution How can mixtures be classified? Unit 2 Lesson 3 Pure Substances and Mixtures Simple Solution How can mixtures be classified? A heterogeneous mixture is one that does not have a uniform composition. A homogeneous mixture has the same composition throughout. Copyright © Houghton Mifflin Harcourt Publishing Company 17

How can mixtures be classified? Unit 2 Lesson 3 Pure Substances and Mixtures How can mixtures be classified? A suspension is a heterogeneous mixture. Particles in a suspension are spread throughout a liquid or gas, but are too large to stay mixed unless shaken or stirred. Particles settle in suspensions. Copyright © Houghton Mifflin Harcourt Publishing Company 18

How can mixtures be classified? Unit 2 Lesson 3 Pure Substances and Mixtures How can mixtures be classified? A solution is a homogeneous mixture in which one substance is dissolved in another substance. Colloids have particles that are unevenly spread throughout the mixture. Unlike a suspension, particles in colloids are too small to settle out of the mixture. Copyright © Houghton Mifflin Harcourt Publishing Company 19

Solution is another name for what type of matter? Compound Homogeneous mixture Heterogeneous mixture

Muddy water is an example of what type of mixture? Colloid Solution suspension

Work on homework, lesson 3 until the bell rings…………………pages 113.