Chemical Reaction Predictions

A brief review….

Types of Chemical Reactions 1)Single Displacement 2)Double Displacement 3)Decomposition 4)Synthesis 5)Combustion

Single Displacement A +BC  AC + B A +BC  AC + B One element shoves the other element out! One element shoves the other element out! Ex. Ca + AlCl 3  CaCl 2 + Al Ex. Ca + AlCl 3  CaCl 2 + Al

Double Displacement AB + CD  AC + BD AB + CD  AC + BD Elements switch partners ! Elements switch partners ! Ex. Na 3 PO 4 + BaCl 2  Ba 3 (PO 4 ) 2 + NaCl Ex. Na 3 PO 4 + BaCl 2  Ba 3 (PO 4 ) 2 + NaCl

Decomposition AB  A + B AB  A + B Breaking chemical compound up, going from BIG to SMALL ! Breaking chemical compound up, going from BIG to SMALL ! Ex. Au 2 O 3  Au + O 2 Ex. Au 2 O 3  Au + O 2

Synthesis A + B  AB A + B  AB Joining! Making new chemical compound ! Joining! Making new chemical compound ! Mg + N 2  Mg 3 N 2 Mg + N 2  Mg 3 N 2

Combustion HYDROCARBON (compound made up of just Cs and Hs) + O 2  CO 2 + H 2 O HYDROCARBON (compound made up of just Cs and Hs) + O 2  CO 2 + H 2 O Chemical reactions involve a compound burning. Chemical reactions involve a compound burning. Ex. C 2 H 6 + O 2  CO 2 + H 2 O Ex. C 2 H 6 + O 2  CO 2 + H 2 O

Practice 1)Zinc metal combines with hydrochloric acid (HCl). 2)Sodium sulfide combines with magnesium oxide. 3)Sodium metal combines with sulfur. 4)Calcium oxide breaks down. 5)C 4 H 8 burns 6)Gandalf combines aluminum metal with sodium hydroxide in solution. What does he produce?]

Aqueous Solutions Compounds dissolved into water. Compounds dissolved into water. Can contain molecules or ions in a solution. Can contain molecules or ions in a solution. How do you distinguish between ion or molecule? How do you distinguish between ion or molecule?

DISSOCIATION !! The ability of a compound to breakdown in a solution into individual ions The ability of a compound to breakdown in a solution into individual ions Ionic Compounds Ionic Compounds Break down into cations and anions Break down into cations and anions Electrical conductors—ions flow through solution Electrical conductors—ions flow through solution Molecular Compound Molecular Compound Compound remains intact as “molecules,” no breakdown Compound remains intact as “molecules,” no breakdown Generally NOT electrical conductors Generally NOT electrical conductors

Dissociation Reactions 1)NaCl 2)CaCl 2

Nonelectrolyte NO dissociation of the compound into anions and cations NO dissociation of the compound into anions and cations Compound remains in its molecular form when dissolved in a solution Compound remains in its molecular form when dissolved in a solution No conduction of electricity No conduction of electricity Ex. Pure water, molecular compounds, organic compounds Ex. Pure water, molecular compounds, organic compounds

Electrolytes Compound dissolved in a solution that breaks down into cations and anions. Compound dissolved in a solution that breaks down into cations and anions. Dissociates into enough ions to conduct electricity. Dissociates into enough ions to conduct electricity. Strong vs. weak—dependent on the amount of ions in the solution Strong vs. weak—dependent on the amount of ions in the solution

Strong Electrolyte LOTS of ions present in solution LOTS of ions present in solution Light bulb burns brightly ! Light bulb burns brightly ! Complete dissociation of the compound into ions Complete dissociation of the compound into ions Good electrical conductor Good electrical conductor Ex. NaCl, all soluble ionic compounds, very few molecular compounds Ex. NaCl, all soluble ionic compounds, very few molecular compounds

Weak Electrolyte Compound is at a crossroads Compound is at a crossroads part dissociates into ions—partial ionization part dissociates into ions—partial ionization part still exists in the molecular form part still exists in the molecular form Some electrical conduction but poor Some electrical conduction but poor Dimly lit light bulb Dimly lit light bulb Ex. Acetic acid, carboxylic acid/amines Ex. Acetic acid, carboxylic acid/amines

What is the concentration ([ ]) of a particular ion in solution? Sometimes [ion] = [compound], but not always Sometimes [ion] = [compound], but not always An ion can have only ONE concentration in a solution An ion can have only ONE concentration in a solution May have multiple sources for one ion. What do you do then? (add them up) May have multiple sources for one ion. What do you do then? (add them up)

Example 1: Hercules has obtained an aqueous solution of M Na 2 SO 4 and M NaCl. What is the concentration (in molarity) of each ion present in the solution? Total ion concentration?

Example 2: Oral Rehydration Therapy (ORT) is an electrolyte solution containing 3.5 g NaCl, 1.5 g KCl, 2.9 g sodium citrate (Na 3 C 6 H 5 O 7 ) and 20.0 g glucose (C 6 H 12 O 6 ) in 1 liter. What is the molarity of each ion/molecule in a solution of ORT? Oral Rehydration Therapy (ORT) is an electrolyte solution containing 3.5 g NaCl, 1.5 g KCl, 2.9 g sodium citrate (Na 3 C 6 H 5 O 7 ) and 20.0 g glucose (C 6 H 12 O 6 ) in 1 liter. What is the molarity of each ion/molecule in a solution of ORT? Hint: sodium citrate is a strong electrolyte, glucose is a nonelectrolyte Hint: sodium citrate is a strong electrolyte, glucose is a nonelectrolyte

Solubility How much solute dissolves in a solution to produce a saturated solution How much solute dissolves in a solution to produce a saturated solution Temperature and Pressure dependent Temperature and Pressure dependent Increase with increasing temperature Increase with increasing temperature Increases with decreasing temperature (ex. Water in lake) Increases with decreasing temperature (ex. Water in lake) Pressure increases, solubility increases (ex. Soda can) Pressure increases, solubility increases (ex. Soda can)

Particles move back and forth from being dissolved to leaving a solution—equilibrium is reached when this movement is balanced. Particles move back and forth from being dissolved to leaving a solution—equilibrium is reached when this movement is balanced. A point is reached where adding more solute to a solution will prevent the solute from dissolving in the solution. A point is reached where adding more solute to a solution will prevent the solute from dissolving in the solution.

Types of Solutions 1) Saturated 1) Saturated Maximum amount of solute that can be dissolved in a solvent Maximum amount of solute that can be dissolved in a solvent Certain temperature and pressure Certain temperature and pressure 2) Unsaturated 2) Unsaturated Solution with LESS solute than the maximum solute amount at a certain temperature and pressure Solution with LESS solute than the maximum solute amount at a certain temperature and pressure More solute can be added and dissolved in the solution More solute can be added and dissolved in the solution 3) Supersaturated 3) Supersaturated Contains MORE solute than the maximum solute amount Contains MORE solute than the maximum solute amount

Solubility Diagrams

Solubility Rules How do we determine which compounds will dissolve in water or not? How do we determine which compounds will dissolve in water or not? Based on data, patterns have been observed and helped develop the rules we follow Based on data, patterns have been observed and helped develop the rules we follow

Which compounds are soluble in water? 1) BaCl 2 2) Pb (NO 3 ) 2 3) Na 2 S 4) BaCO 3 5) PbS

Your Turn……. NaCl NaCl KBr KBr KNO 3 KNO 3

AP Question Snow White conducts a complete combustion of a hydrocarbon with excess oxygen. This combustion produces equimolar quantities of carbon dioxide and water. What is a possible molecular formula for the compound? Snow White conducts a complete combustion of a hydrocarbon with excess oxygen. This combustion produces equimolar quantities of carbon dioxide and water. What is a possible molecular formula for the compound? A) C 2 H 2 A) C 2 H 2 B) C 2 H 6 B) C 2 H 6 C) C 4 H 8 C) C 4 H 8 D) C 6 H 6 D) C 6 H 6