Elements, Compounds and Mixtures Worksheet 1. Elements: -a pure substance containing only one kid of atom -an element is always uniform all the way through (homogeneous) -an element cannot be sepearted into simpler materials (Except during nuclear reactions) -over 109 existing elements are listed and classified on the periodic table 2. Comounds: -A pure substance containing two or more kinds of atoms -the atoms are chemically combined in some way. Often times (but not always) they come together to form groups of atoms called molecules -A compound is always homogeneous (uniform) -compounds cannot be separated by physical means. Separating a compound requires a chemical reaction -the properties of a compound are usually different than the properties of the elements it contains 3. Mixtures: -Two or more elements ir compounds NOT chemically combined. -No reaction between substances -mixtures can be uniform (called homogeneous) and are known as solutions -Mixtures can also be non-uniform (called heterogeneous) -mixtures can be separated into their components by chemical or physical means -the properties of a mixture are similar to the properties of its components 4. Diamond (C): Element 5. Air: Mixture 6. Kyrpton (K): Element 7. Water (h20): Compund 8. Ammonia (NH3): Compound 9. Wood: Mixture 10. Dry ice (CO2): Compound 11. Sugar (C6H12O6): Compound 12. Sulfuric acid (H2SO4): Compound 13. Bismuth (Bi): Element 14. Alcohol (CH3OH): Compound 15. Salt (NaCl): Compound 16. Bronze: Mixture 24. Titanium(Ti): Element 17. Baking soda (NaHCO3): Compound 25. Iron (Fe): Element 18. Milk: Mixture 26. Electricity: Not any of them 19. Gasoline: Mixture 27. Popcorn: Mixture 20. Uranium (U): Element 28. A dog: Mixture 21. Pail of garbage: Mixture 29. Gold (Au): Element 22. Energy: Not any of them 30. Pizza: Mixture 23. ink: Mixture 31. Concrete: Mixture