Physical Science - PowerPoint PPT Presentation

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Physical Science

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  1. Physical Science Chemical Properties

  2. Atoms and Molecules An Atom is made up of protons, electrons, and neutrons. An Element is a unique number of protons. When 2 or more atoms combine together chemically, it is called a molecule.

  3. Molecular Elements These are allotropes of carbon

  4. Compounds 2 or more elements combined in a molecule

  5. What is a Chemical Reaction? CH4 + 2O2 CO2 + 2H2O It is the rearrangement of atoms to form new molecules.

  6. What is a Chemical Reaction? CH4 + 2O2 CO2 + 2H2O It is the rearrangement of atoms to form new molecules.

  7. What is a Chemical Reaction? CH4 + 2O2 CO2 + 2H2O It is the rearrangement of atoms to form new molecules.

  8. What is a Chemical Reaction? Some chemical reactions are exothermic They release energy as heat, light, or other forms.

  9. What is a Chemical Reaction? Some chemical reactions are endothermic They absorb energy from the environment to proceed.

  10. Chemical Properties Chemical properties can only be observed when the substances in a sample of matter are ________________. _____ and _____ are examples of chemical properties

  11. Chemical Properties • Chemical properties can only be observed when the substances in a sample of matter are ________________. • Changing into different substances • _____ and _____ are examples of chemical properties

  12. Chemical Properties • Chemical properties can only be observed when the substances in a sample of matter are ________________. • Changing into different substances • _____ and _____ are examples of chemical properties • Flammability • Reactivity

  13. Triggers to Chemical Reactions Most reactions do not occur spontaneously. Most require some trigger to get started. This could be a spark or even a touch. Let’s watch a fun video of a chemical reaction that is sensitive to the touch!

  14. Nitrogen Triiodide 2 NI3 (s) → N2 (g) + 3 I2 (g),

  15. Nitrogen Triiodide Decomposition

  16. Some Fun Experiments Mr. Taylor Does Nitrogen Triiodide http://www.youtube.com/watch?v=hERVtZEZrFQ

  17. Some Fun Experiments THERMITE! http://www.youtube.com/watch?v=sjLgzgflCk8

  18. Some Fun Experiments Pure Metallic Sodium in Water! http://www.youtube.com/watch?v=gFnNXkcoDSs

  19. Recognizing Chemical Change • Chemical changes are taking place if you see a _____, ______, or ______. • Change in color • Production of a gas • Formation of a precipitate **If you are watching by recording, send me the sentence above with the answers**

  20. Mixtures • Iron and Sulfur powder in a the mixture • So, it is hypothesis time: How can we separate the iron from the sulfur? Enter some ideas in the chat box.

  21. Mixtures • Iron and sulphur – the mixture • How can we separate the iron from the sulphur? • Use a magnet! • Iron is magnetic, sulfur is not...

  22. Turning an iron-sulphur mixture into a Compound Heat Fe + S FeS

  23. When iron and sulphur react + sulphur (S) atoms iron (Fe) atoms

  24. When iron and sulphur react + sulphur (S) atoms iron (Fe) atoms iron sulphide (FeS) molecules

  25. Differences between compounds and mixtures MIXTURES COMPOUNDS • Mixtures can be separated easily • Compounds can not be separated

  26. Differences between compounds and mixtures MIXTURES COMPOUNDS • Mixtures can be separated easily • Mixture have the properties of the substances present in it • Compounds can not be separated • Compounds do not have the properties of the elements

  27. Differences between compounds and mixtures MIXTURES COMPOUNDS • Mixtures can be separated easily • Mixture have the properties of the substances present in it • No chemical change takes place when a mixture is made • Compounds can not be separated • Compounds do not have the properties of the elements • A compound is always formed due to a chemical reaction

  28. Differences between compounds and mixtures MIXTURES COMPOUNDS • Mixtures can be separated easily • Mixture have the properties of the substances present in it • No chemical change takes place when a mixture is made • There is no heat taken in or given out when a mixture is made • Compounds can not be separated • Compounds do not have the properties of the elements • A compound is always formed due to a chemical reaction • Heat is either taken in or given out when a compound is made

  29. Differences between compounds and mixtures MIXTURES COMPOUNDS • Mixtures can be separated easily • Mixture have the properties of the substances present in it • No chemical change takes place when a mixture is made • There is no heat taken in or given out when a mixture is made • A mixture can contain elements in any proportion • Compounds can not be separated • Compounds do not have the properties of the elements • A compound is always formed due to a chemical reaction • Heat is either taken in or given out when a compound is made • A compound always contains the elements in fixed proportions, e.g. FeS contains 7g of iron to 4g of sulphur