Elements compounds and mixtures notes
- 1. Elements, Compounds and Mixtures Holt: Chapter 4 Fusion: Unit 3, Lesson 5
- 2. Mixtures • A mixture is a combination of two or more substances that are not chemically combined. • No chemical changes • Sometimes you can see the components, sometimes you cannot • Not mixed in a definite ratio • Separate through physical methods • Distillation- uses boiling points • Magnets- use magnetism • Centrifuge- uses density • Filtering- separates according to size • Examples:
- 3. Types of Mixtures •Solutions •Suspensions •Colloids
- 4. Solutions • A mixture that appears to be a single substance • Process by which they spread is dissolving • Solute- the substance being dissolved • Solvent- the substance doing the dissolving (water is the universal solvent) • Particles never settle, cannot be filtered; do not scatter light Examples of Different States in Solutions Gas in gas Dry air (oxygen in nitrogen) Gas in liquid Soda (carbon dioxide in water) Liquid in liquid Antifreeze (alcohol in water) Solid in liquid Salt water (salt in water) Solid in solid Brass (zinc in copper)
- 5. Concentration of Solutions • Concentration- the measure of the amount of solute dissolved in a solvent • Can be expressed in grams of solute per milliliter of solvent (g/mL) • Remember…solubility is the ability of a substance to dissolve • Mixing, heating and crushing can help dissolve more quickly
- 6. Suspensions • Suspension- is a mixture in which particles of a material are dispersed throughout, but are large enough to settle out. • Suspensions CAN be separated by filtration • Scatter light
- 7. Colloids • A colloid is a mixture in which the particles are dispersed throughout and not heavy enough to settle out • Particles are small and fairly well mixed; scatter light • Cannot be separated by filtration • Examples:
- 8. Elements • Element- a pure substance that cannot be separated into simpler substances by chemical or physical means • Pure substance- is a substance in which there is only one type of particle • Particles are atoms • Each element has unique properties- not dependent on how much of an element you have • Remember…characteristic properties? Physical and chemical properties? • Elements do share some properties • Grouped on the periodic table by properties
- 9. Categories of Elements Metals Nonmetals Metalloids • shiny • Good conductors of heat and electricity • Malleable • Ductile • dull • Poor conductors of heat and electricity • Solids tend to be brittle and not malleable • Have properties of both metals and nonmetals • Semi-conductors
- 10. Compounds • Compound- a pure substance composed of two or more elements that are chemically combined • Combine by reacting, undergoing chemical change • Particles are called molecules, which are formed when atoms of two or more elements combine • Compounds are DIFFERENT from the elements that make it • Elements join in specific mass ratios • Ex: H2O = 1:8
- 11. Familiar Compounds Compound Elements combined Table salt Sodium and chlorine Water Hydrogen and oxygen Vinegar Hydrogen, carbon, oxygen Carbon dioxide Carbon, oxygen Baking soda Sodium, hydrogen, carbon, oxygen
- 12. Properties of Compounds • Each compound has its own physical properties • Can be identified by chemical properties • A compound’s properties differ from the elements that formed it
- 13. Breaking down Compounds • Broken down through chemical changes • Sometimes have to be broken into simpler compounds, then elements • Two ways to break down: apply heat or electric current