 A solid gold chain OR A melted gold chain?

LLaw of Conservation of Mass? MMatter cannot be created or destroyed… so what happens to it? NNomenclature? TThe fancy term for how we name compounds. IIonic compounds (NEVER uses prefixes) ex. Li 2 O CCovalent Compounds (uses prefixes) ex. N 2 O 2 DDiatomic Elements? HH 2, N 2, O 2, F 2, Cl 2, Br 2, I 2,

 Chemical Reaction : When one substance (or more) is changed into one (or more) new substances [5 reaction types we’ll learn soon]  Reactants : those elements or compounds on the left which undergo a reaction.  Products : Those elements or compounds on the right which were produced in a reaction.  Coefficient : the large number in front of the formula of a compound. Tells the number of molecules or atoms or moles of an element.  What’s the coefficient here??? 3NO 2

1. Determine the correct formulas for all the reactants and products in the reaction. 2. Begin balancing with the most complicated- looking group. A polyatomic ion that appears unchanged on both sides of the equation can be counted as a single unit. 3. Save the elemental (single elements) reactant and products for last. Keep your eye out for diatomic molecules such as oxygen-O 2, hydrogen-H 2, and all halogens. 4. If you get stuck, double the most complicated- looking group and try again. 5. Finally, make sure that all coefficients are in the lowest-possible ratio.

 Since “mass is conserved”, we can’t add or subtract atoms whenever a reaction occurs.  Let’s look at our first reaction… O 2 (g) + Fe (s) → FeO (s) 22 O 2 (g) + H 2 (g) → H 2 O (l) 2 2 Cl 2 + NaBr → Br 2 + NaCl 22 sodium + chlorine  sodium chloride

 Cs + P  Cs 3 P NaNO 3  NaNO 2 + O 2 Ca(NO 3 ) 2 + K 3 PO 4  Ca 3 (PO 4 ) 2 + KNO 3 C 2 H 4 + O 2  CO 2 + H 2 O CaO + H 2 O  Ca(OH) 2

Two or more substances combine to form one new compound. A + X  AX Na (s) + Cl 2 (g)  Na (s) + Cl 2 (g)  H 2 (g) + O 2 (g)  H 2 (g) + O 2 (g)  NaCl (s) H 2 O (l) H 2 O (l)

A single compound undergoes a reaction that produces two or more simpler substances AX  A + X H 2 O (l)  H 2 (g) + O 2 (g) NaCl (g)  Na (s) + Cl 2 (g) NaCl (g)  Na (s) + Cl 2 (g) It often requires energy to make decomposition reactions happen.

For A to take B’s place, A must be more reactive than B A + BX  AX + B Mg (s) + HCl (aq) → MgCl 2 (aq) + H 2 (g) Fe(s) + CuSO 4 (aq) → FeSO 4 (aq) + Cu(s)

Lithium Potassium Calcium Sodium Magnesium Aluminum Zinc Chromium Iron Nickel Lead Hydrogen Bismuth Copper Mercury Silver Platinum Gold  Metals can replace other metals provided that they are above the metal that they are trying to replace hydrogen  Metals above hydrogen can replace hydrogen in acids. sodium  Metals from sodium upward can replace hydrogen in water

Fluorine Chlorine Bromine Iodine Halogens can replace other halogens in compounds, provided that they are above the halogen that they are trying to replace. NaCl(s) + F 2 (g)  NaF(s) + Cl 2 (g) MgCl 2 (s) + Br 2 (g)  ??? No Reaction ???

The ions of two compounds exchange places in an aqueous solution to form two new compounds. AX + BY  AY + BX HCN + CuSO 4  H 2 SO 4 + Cu(CN) 2

A substance combines with oxygen, releasing a large amount of energy in the form of light and heat. The burning of any hydrocarbon fuel (natural gas, wood, gasoline, etc.) CH 4 (g) + O 2 (g)  CO 2 (g) + H 2 O(g)

If I want to make a glass of water, what all do I need? Remember how to convert moles to grams? H 2 (g) + O 2 (g)  H 2 O (l) H 2 (g) + O 2 (g)  H 2 O (l) 1.A balanced chemical equation 2 2. I need to know how much H 2 and O 2 are needed grams / 1 mole H 2 …and we’ve got 2 moles 2 mol H 2 1 mol H g = 4.04 g = 4.04 g H 2 3. Repeat these calculations for O 2 & H 2 O