Earth Chemistry

1. Earth Chemistry

2. Matter - is anything that has mass and takes up space • The amount of matter in an object is called mass • All matter has measurable properties which helps identify it

3. Physical properties • Properties that can be observed without changing the composition of the matter • Examples: Color, hardness, state of matter, density

4. Chemical properties • Properties that describe how matter reacts to other substances • Example: flammable

5. Matter has 4 Phases/States • Solid– particles are packed together and only vibrate • Liquid– particles are less packed together than solids and slide past each other • Gas– particles are far apart and move quickly • Plasma – similar in properties to a gas but can conduct electricity in certain conditions

8. Elements • Are substance that cannot be broken down into simpler substances by chemical means • Each element is made of its on atom • Are represented by a symbol • They are organized into the periodic table

9. Periodic Table • It has a series of boxes that represent each element • The parts in each box • Atomic Number – at the top • Represents the number of protons • Symbol – represent the name of the element • Atomic mass – at the bottom • Represent the total number of protons plus neutrons

10. Oxygen 8 O 15.999 Atomic Number Symbol Atomic Mass

11. Periodic Table Set Up • Rows • Go across • The atomic number increases by one each time you go across • Columns (called families or groups) • Go down • Each group has a name • All elements in the same group have the same number of valence electrons so they react similarly • As you go down they get larger

14. Atoms – the smallest unit of an element (made of mostly empty space) • Two parts: • Nucleus • Protons: • Have a positive charge • Mass = ~ 1 amu • Neutrons: • No charge • Mass = ~ 1 amu • Electron cloud • Electron: • Have a negative charge • Mass = 9.1 x 10-31 • Force of attracted to the protons in the nucleus hold them in place

17. An elements protons can’t change or it is not the same element But it can change neutrons or electrons Neutral – have equal number of all particles Isotopes – a different number of neutrons Changes the mass Ions – have a different number of electrons If extra – they have a negative charge If fewer – they have a positive change

18. Valence electrons – the electrons that are in the outer shell of an atom • They determine: • The atoms properties • What atoms they can bond with • The goal is to have the outer shell full (eight electron in outer shell) • If the outer shell is full it’s called inert (or inactive) – won’t react

20. When atoms bond it is chemically • Forms a compounds • Compounds have properties are different than the elements in it • Example: Water

21. Representing compounds • Chemical formulas – a combination of letters and numbers that the makeup of the compound • Include: • Symbols • Subscripts = little numbers to the lower right • Tells the number of atoms of that element • Coefficient – large number in the front • Tells the number of molecules

22. Example of Chemical Formula C6H12O6 4C6H12O6

23. To show how substance react with each other we use a chemical equation • Parts of the equation • Reactants – on the right side of the arrow (starting materials) • Products – on the left side of the arrow (what is made) • All equations must have the number of each type of atom on both sides of the equation

24. Example of Reaction 2 Ag + S      Ag2S

25. How are the substance held together? • Chemical bonds – forces that hold together atoms in a molecule • Bonds can occur if electrons from different atoms are shared or transferred

26. Name of Bonds • Ionic – transfer electrons • Covalent – share electrons

27. Ionic Verses Covalent Bonds

29. Factors Affecting Reaction Rates • Temperature • Surface area/Particle size • Concentration of solution • Pressure • Catalysts • Inhibitors

30. Increasing Surface Area