Elements, Compounds and Mixtures

Elements, Compounds and Mixtures

1. An element is a substance made up of only 1 atom.

2. A mixture is a combination of substances which are not chemically combined.

3. A compound is formed when two or more elements are joined together using a chemical reaction

4. If something reacts chemically:

   • It can change colour
   • A new substance is formed
     • Not all of these will always happen it maybe only one or two.
   • A temperature change will occur

5. The formula for sodium chloride is NaCl

6. The word equation for the reaction between methane and oxygen to produce carbon dioxide and water is:

   • Methane+Oxygen - Carbon Dioxide+Water

7. The main element in sand is silicon dioxide.

8. Crystals are bigger when left to evaporate slowly because the have a longer time to crystallise.

9. DISSOLVE IS WHEN A SOLID AND A LIQUID MIX

   • THE SOLUTION FORMED WILL BE TRANSPARENT.

10. SOLUBLE MEANS IT WILL DISSOLVE

11. INSOLUBLE MEANS IT WON'T DISSOLVE

12. FILTERING ALLOWS SEPARATION OF SOLUBLE AND INSOLUBLE COMPONENTS

13. SOLUTION IS WHEN A SOLID DISSOLVES IN A LIQUID.

14. A SOLVENT IS THE LIQUID THAT THE SOLUTE DISSOLVES IN.

15. A SOLUTE IS THE SOLID THAT DISSOLVES TO FORM A SOLUTION

16. DISTILLATION HAS THREE STEPS:

    • EVAPORATION
    • CONDENSATION
    • COLLECTION

17. AN ALLOY IS A MIXTURE OF TWO ELEMENTS, ONE THAT HAS TO BE A METAL

    • E.G. BRASS (MAIN METALS COPPER AND ZINC

18. A POLYMERS ARE LARGE MOLECULES WITH LONG CHAINS OF CARBON ATOMS

    • MAN MADE POLYMERS
      • E.G. POLYETHYLENE AND POLYSTYRENE.
    • NATURAL POLYMERS
      • E.G. CELLULOSE AND AMBER

19. BIOGRADABLE MEANS CAPABLE OF BEING BROKEN DOWN BY MICRO-ORGANISMS

    • ADVANTAGES
      • THE TAKE LESS TIME TO BREAK DOWN
      • THEY ARE RENEWABLE
      • GOOD FOR ENVIROMENT
      • REQUIRE LESS ENERGY TO PRODUCE

20. ELEMENTS AND COMPOUNDS HAVE SHARP, FIXED FREEZING AND BOILING POINTS.

21. MIXTURES DO NOT HAVE FIXED FREEZING AND BOILING POINTS BECAUSE THE COMPOSITION OF THE MIXTURE HAS AN EFFECT.

22. WATER HAS THE BOILING POINT OF 100*c

23. AS THE AMOUNT OF SALT INCREASES THE BOILING TEMPERATURE INCREASES