Chapter 2 Section 1: Classifying Matter. Classification of Matter. Classification of Matter 9/5/15

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1 Chapter 2 Section 1: Classifying Matter Classification of Matter Now that we have defined chemical and physical properties of matter, we can use that to help us classify it. One way chemists classify matter is based on its purity. Classification of Matter Pure Substance Matter that has only 1 set of chemical and physical properties. Example: Pure water always has the exact same chemical and physical properties under the same conditions. If water ever tastes different then it isn t pure water; it fits into our next category. 1

2 Classification of Matter Mixture Two or more pure substances mixed together. Each substance in the mixture retains its own set of chemical and physical properties. Example: Even though Copper it may and look Zinc different, can be it is mixed still copper together and zinc. to Each produce metal brass. retains its own properties like melting point. Classification of Matter Mixture Two or more pure substances mixed together. Each substance in the mixture retains its own set of chemical and physical properties. Unlike pure substances, mixtures can always be separated by physical means. How could we separate the copper and zinc back out? Mixtures Mixture Two or more pure substances mixed together. Each substance in the mixture retains its own set of chemical and physical properties. If a sample of sand contains iron and salt, how could you separate them from the other minerals? 2

3 Mixtures Some mixtures are more pure than others. Heterogeneous mixture Uneven distribution of substances. (Very impure) - You can see the different parts. Examples: Sand Granite Wood Mixtures Some mixtures are more pure than others. Heterogeneous mixture Uneven distribution of substances. (Very impure) - You can see the different parts. Examples: Milk Blood Mixtures Homogeneous Mixture Components are evenly mixed. (More pure than heterogeneous) - Cannot see the parts. Salt water contains salt and water, but are mixed all the way to the atomic level, but it can still be separated by physical means. Seawater distillation plant 3

100 80 60 40 20 0 1st Qtr 2nd Qtr East West North 3r d Qtr 4th Qtr 9/5/15 Colloids In a colloid the particles are mixed together but not dissolved.

4 st Qtr 2nd Qtr East West North 3r d Qtr 4th Qtr 9/5/15 Colloids In a colloid the particles are mixed together but not dissolved. The particles are relatively large and are kept permanently suspended. Colloids A colloid will not separate upon standing. The particles are constantly colliding, and this allows a colloid to scatter light thus colloids often seem cloudy. 4

5 Suspensions Suspensions are mixtures that separate into layers as time passes due to the size of the particles. They also disperse light at times. Solutions A solution is a type of homogeneous mixture formed when one substance dissolves in another. It is the best mixed of all mixtures. A solution always has a substance that is dissolved and a substance that does the dissolving. The substance that is dissolved is the solute and the substance that does the dissolving is the solvent. Ocean water is a solution 5

The universal solvent: Water Water as a solvent Many liquid solutions contain water as the solvent. Ocean water is basically a water solution that contains many salts.

6 The universal solvent: Water Water as a solvent Many liquid solutions contain water as the solvent. Ocean water is basically a water solution that contains many salts. Body fluids are also water solutions. Types of solutions Solute Solvent Example Gas Gas Air (oxygen in nitrogen) Gas Liquid Soda water (carbon dioxide in water) Solid Liquid Ocean water (salt in water) Solid Solid Gold jewelry (copper in gold) Metals dissolved in metals are called alloys. 6

7 Air is a solution of oxygen and other gases dissolved in nitrogen Pure Substances Pure substances can also be divided into 2 categories: compounds and elements. Pure Substances Compound Two or more elements chemically bonded together. Examples: Carbon Dioxide (CO 2 ) Water (H 2 O) Salt (NaCl) Sucrose (C 12 H 22 O 11 ) 7

8 Pure Substances Compounds have only 1 set of properties. They cannot be separated by any physical process. - Can only be separated by a chemical reaction. Water can be separated into Hydrogen and Oxygen by a process called Electrolysis. Pure Substances Elements Substances made up of only one type of atom. - Cannot be separated by any physical OR chemical process. Examples: Carbon Helium Gold Can be separated physically Mixture Matter Cannot be separated physically Pure Substance Can see the parts Cannot see the parts Can be separated chemically Cannot be separated Heterogeneous Mixture Homogeneous Mixture Compound Element Most impure Most pure 8

A Matter of Fact. Mixtures, Elements and Compounds

A Matter of Fact. Mixtures, Elements and Compounds A Matter of Fact Mixtures, Elements and Compounds Mixtures, elements, compounds Scientists like to classify things. One way that scientists classify matter is by its composition. Ultimately, all matter