Review

titanium (lll) oxide trihydrate Ti2O3 · 3 H2O titanium (lll) oxide trihydrate

hydrobromic acid HBr

chloric acid HClO3

dicarbon hexachloride C2Cl6

nitrous acid HNO2

HF hydrofluoric acid

Chemical Reactions

2.0 - Systems What are chemical reactions? new products are formed with new properties some bonds are broken and some new chemical bonds are formed atoms are rearranged

Physical Change Chemical Change intramolecular bond intermolecular bond

When we study reactions, we talk about systems system: part of the universe being studied closed system: things cannot enter or leave the system matter

Closed System

Closed System

When we study reactions, we talk about systems system: part of the universe being studied closed system: things cannot enter or leave the system open system: things can enter or leave the system matter

Open System

Chemical reactions in closed systems ALWAYS follow four basic laws: The Law of Conservation of Mass: the total mass in a reaction does not change The Law of Conservation of Atoms: the total # and type of atoms does not change The Law of Conservation of Electrical Charge: the total electrical charge does not change 4. The Law of Conservation of Energy: the total energy does not change

Writing chemical reactions Word equation: uses words to describe a reaction solid copper (l) carbonate + water → carbon dioxide gas + copper (l) hydroxide

Writing chemical equations Chemical equation: uses symbols, subscripts, and coefficients to describe a reaction reactants products Cu2CO3(s) + H2O(l) → CO2(g) + 2 CuOH(aq) subscripts phase coefficient

Pb2+(aq) + I-(aq) → PbI2(s) Phase Symbols phase symbols: symbols that tell you what phase the reactants and products are in (s) = solid______________ (l) = liquid______________ (g) = gas______________ (aq) = aqueous______________ Pb2+(aq) + I-(aq) → PbI2(s)

There are 7 non-metals that exist in nature as diatomic molecules, or molecules with 2 atoms. These are typically gases. Whenever a reaction is done with these elements, the subscript is always 2! HOFBrINCl

Balancing Equations the four conservation laws must be expressed when writing chemical reactions equations

___Ca2C + ___O2 → ___ Ca + ___CO2 ___Pb(NO3)2 + ___ NaI → ___PbI2 + ___ NaNO3 ____ N2 + _____ H2 → _____NH3 ____ KClO3 → ____ KCl + ____O2 ____ NaCl + ____ F2 → ____ NaF + ____ Cl2 _____ H2 + ___ O2 → ____ H2O _____ AgNO3 + ____ MgCl2 → ____ AgCl + ____ Mg(NO3)2 ____ AlBr3 + ___K2SO4 → ___KBr + ___ Al2(SO4)3 ____CH4 + ____ O2 → ____ CO2 + ____ H2O ____ C3H8 + ____ O2 → ____ CO2 + ____ H2O ____ C5H12 + ____ O2 → ____ CO2 + ____ H2O Challenge: ____ C19H17NO3 + ____ O2 →____ CO2 + ____ H2O + ____ N2 2 2 2 3 2 2 2 3 2 2 2 2 2 2 2 3 6 2 2 5 3 4 8 5 6 4 87 76 34 2

sodium ion reacts with sulfate ion to produce sodium sulfate Step 1: Write the equation. Step 2: Balance the equation Na+ + SO42-  Na2SO4 2Na+ + SO42-  Na2SO4

Boron mononitride reacts with fluorine to give boron trifluoride and nitrogen BN + F2  BF3 + N2

Boron mononitride reacts with fluorine to give boron trifluoride and nitrogen BN + F2  BF3 + N2 2 3 2

Solid sodium reacts with chlorine gas to produce solid sodium chloride. Na(s) + Cl2(g)  NaCl(s) 2 2

H2O(l) + Na2O(s)  NaOH(aq) Liquid water reacts with powdered sodium oxide to produce aqueous sodium hydroxide. H2O(l) + Na2O(s)  NaOH(aq) 2

Types of Chemical Reactions

H2(g) + Cl2(g) → 2HCl(g) AgNO3(aq) + NaCl → AgCl(s) + NaNO3(aq) 2Ag2O(s) → 4Ag(s) + O2(s) C5H12 + 8O2(g) → 5CO2(g) + 6H2O(l) Cl2(aq) + 2KI(aq) → I2(aq) + 2KCl(aq) HCl(aq) + NaOH(aq) → H2O(aq) + NaCl(aq)

Types of Chemical Reactions synthesis (or combination): A + B → AB two or more elements combine to form a compound

Types of Chemical Reactions synthesis (or combination): A + B → AB two or more elements combine to form a compound

Types of Chemical Reactions decomposition: AB → A + B a single compound breaks down into simpler substances

Types of Chemical Reactions decomposition: AB → A + B a single compound breaks down into simpler substances

Types of Chemical Reactions single replacement: A + BX → B + AX an element reacts with a compound one element replaces another

Types of Chemical Reactions single replacement: A + BX → B + AX an element reacts with a compound one element replaces another

Types of Chemical Reactions double replacement: AB + XY → AY + XB two compounds react two elements switch places

Types of Chemical Reactions double replacement: AB + XY → AY + XB two compounds react two elements switch places

Types of Chemical Reactions combustion: CaHbY + O2 → H2O + CO2 an organic compound (compound with C and H) reacts with O2 to produce heat, H2O, and CO2

Types of Chemical Reactions combustion: CaHbY + O2 → H2O + CO2 an organic compound (compound with C and H) reacts with O2 to produce heat, H2O, and CO2

Types of Chemical Reactions neutralization: HX + YOH → H2O + XY an acid reacts with a base (molecule with OH) to produce water and salt