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Mixture-Substances powerpoint presentation
- 1. Grade 7 Science Mixtures& Pure Substances
- 2. MATTER Heterogeneous mixture Is it uniform throughout? No Homogeneous Yes Canit be separated by physical means? Pure Substance Homogeneous Mixture (solution) Can it be decomposed into other substance by a chemical process? Element Compound No yes No yes
- 3. Mixed or Pure? Suppose you pick up a rock on the beach. You see there are some parts of it that are grey, white, blue. You conclude that the different-coloured parts of the rock must be different types of matter. Is this a reasonable conclusion?
- 4. Mixed or Pure? With a partner, select two of the following pairs of items and list as many differences as you can: Vinegar and water Aluminum foil and plastic wrap Steel and glass Molasses and cooking oil Metal paper clips and saw dust
- 5. Mixtures vs. Pure Substances Mixtures... MAY have distinct visible components. MAY appear uniform throughout.
- 6. They arethe physical combination of two or more pure substances. + Sugar Water = ?
- 7. Examples of Mixtures… •saltwater, kool-aid •chocolate chip cookie •muddy water •salad dressing
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- 9. Pure Substances... ALWAYSappear as uniform throughout They contain either a single atom or two or more atoms chemically combined to form a different substance.
- 10. Limestone- A PureSubstance (Calcium Carbonate) Limestone is a sedimentary rock composed of calcium carbonate (CaCO3). Has many uses: including as building material, filler in products such as toothpaste or paints.
- 11. Water- A PureSubstance Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds.
- 12. Examples of Pure Substances •sugar(C12H22O11) •gold (Au), copper (Cu) •carbon dioxide (CO2) •oxygen (O2)
- 13. USING THE PARTICLETHEORY OF MATTER WE CAN DISTINGUISH BETWEEN A PURE SUBSTANCE AND A MIXTURE Pure Substance: has only ONE type of particle Example: gold, iron Mixture: has 2 or more types of substance in it. We can also say it has 2 or more types of particles mixed together Example: sweetened water A Quick Review of chapter so far:
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- 15. •Pure Substances ALWAYSappear as uniform (the same) throughout Pure Substances:
- 16. Mixtures are thecombination of two or more types of substances. Sugar – Water- Mixture pure substance pure substance Mixtures:
- 17. The Particle TheoryCan help explain the difference between pure substances and mixtures:
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- 19. Homogeneous Mixture alsocalled solutions can be solid, liquid or gas Stainless steel
- 20. the particles areevenly mixed so that none of the original substances are visible Kool-aid
- 21. they appear tobe ONE substance light passes through unaffected
- 22. Heterogeneous Mixtures alsocalled mechanical mixtures can be solid, liquid or gas Granola bar
- 23. the different partsare visible to the eye (may need a microscope) the particles do not evenly mix Concrete
- 24. Light will reflect perpendicular tothe direction of the beam
- 25. The Tyndall Effect A phenomenon that can be used to distinguish between solutions and what appears to be a solution cannot be used to distinguish between a solution and a pure liquid
- 26. In a Solution... Light passes unaffected (if a student looks at the beaker perpendicular to the direction of the beam they will NOT see it
- 27. In a MechanicalMixture... The light will scatter as it passes through the mixture because all particles are not dissolved (as shown on the left)