Objectives I. Structure of Matter C. Nuclear chemistry: nuclear equations, half-lives, and radioactivity; chemical

Objectives (cont.) III. Reactions A. Reaction types-Synthesis,decomposition and combustion B. Stoichiometry 2. Balancing of equations 3. Mass and volume relations with emphasis on the mole concept, including empirical formulas and limiting reactants

Use 52c When 15 g of gold(III) sulfide reacts with 800 mL of hydrogen gas at 4 atm and 100 degrees C, 10 g of pure gold is recovered. What is the theoretical yield of gold? What is the percent yield of gold?

Use equation #52e How many L of sulfur tetrafluoride will be collected at 25 degrees C from 25 mL of liguid HF (d = 1.34 g/mL)?

Use equation 51b Xenon tetrafluoride gas is charged into a 5L flask containing water at 27 degree C and 800 torr. What is the pressure in the container when the reaction has gone to completion at the same temperature?

Use equation 51e When 35 g of NaCl is dissolved in excess water, sulfur dioxide gas is bubbled into the mixture reacting all of the salt. What would be the M of the HCl formed if the final solution had a volume of 250 mL?

Synthesis Reactions A metal combines with a nonmetal to form a binary salt Example: lithium metal is dropped in nitrogen gas

Metallic oxides and water form bases (metallic hydroxides) Example: solid sodium oxide added to water solid magnesium oxide added to water

Nonmetallic oxides and water form acids. (the nonmetal retains its oxidation number) Example: Carbon dioxide is bubbled into water dinitrogen pentoxide is bubbled into water

Metallic oxides and nonmetallic oxides form salts Example: solid sodium oxide is added to carbon dioxide solid calcium oxide is added to sulfur trioxide

Decomposition Reactions Metallic carbonates decompose into metallic oxide and carbon dioxide Example: magnesium carbonate is heated

Metallic chlorates decompose into metallic chlorides and oxygen Example: magnesium chlorate is heated

Binary compounds break down into their elements Example: Molten sodium chloride is electrolyzed

Sulfurous acid decomposes into sulfur dioxide and water Carbonic acid decomposes into carbon dioxide and water

Ammonium carbonate decomposes into ammonia, carbon dioxide and water Ammonium hydroxide decomposes into ammonia and water (ammonia water)

Hydrogen peroxide decomposes into water and oxygen

Combustion aC x H y + bO 2  cCO 2 + dH 2 O If x/2 is even, then x is coefficient(c) of CO 2 If x/2 is odd, then 2x is coefficient(c) of CO 2 and 2 is coefficient(a) of the hydrocarbon Balance water and oxygen –d = ay/2 –b = c + d/2

C x H y O z + O 2  CO 2 + H 2 O Balance by inspection Other organic compound combustion problems will tell you other products

Stoichiometry See the equation #53 on p. 72 How many grams of fluorine are needed to react with 15.2 g cyanogen gas? How many grams of fluorine are needed to make g of NF 3 ?

Limiting Reactions Using the same equation How many grams of carbon tetrafluoride are made when 12.5 g cyanogen reacts with 3.4 g of fluorine? DO #67a on p. 73

Percent Yield 67B 67C

Gaseous Stoichiometry Density = mass / volume may be a given At STP, 1 mol = 22.4 L for ANY gas At all other conditions, PV = nRT –The units for P must match the R value –All temperatures must be in Kelvin –The volume must be in Liters (dm 3 ) –The number of moles is n

Gas Stoichiometry Moles of solids is mass/formula mass Moles of gas is PV/(RT)

Gas Stoichiometry For the equation: 4PH 3 (g) + 8O 2 (g)  P 4 O 10 (s) + 6H 2 O (g) How many grams of P 4 O 10 is made when 2.4 L of phosphine is burned in air at 22 o C and 137 kPa?

4PH 3 (g) + 8O 2 (g)  P 4 O 10 (s) + 6H 2 O (g) How many L of water at 95 o C and 1.2 atm is made when 14.6 g of tetraphosphorus decoxide is made? How many L of oxygen is needed to burn 2.9 L of phosphine if measured at the same conditions?

4PH 3 (g) + 8O 2 (g)  P 4 O 10 (s) + 6H 2 O (g) How many L of oxygen at STP will be needed to generate 89.1 g of P 4 O 10 ?

NUCLEAR Isotopes are versions of an element with different number of neutrons Most elements exist as a mixture of their isotopes The atomic mass on the periodic table is a weighted average of all the isotopes

Isotope notation Zinc naturally exists as 5 isotopes Zn-64, Zn-66, Zn-67, Zn-68, Zn-70 All zinc has 30 protons; the number represents the mass, hence, a difference in the # of neutrons Another notation is Zn

Nuclear Reactions The sum of the masses are conserved The sum of the charges are conserved a b X + c d Y  a+c b+d Z The superscripts are masses. The subscripts are the atomic numbers/hence, the identity of the element.

Special Nuclear Particles Alpha particle: 4 2 He Beta particle: 0 -1 e Positron: 0 +1 e Neutron: 1 0 n K-capture is an electron (beta particle) Deuterium: 2 1 H Tritium: 3 1 H

Nuclear Reactions The loss of a positron by Y-85 The fission of Pu-239 to give Sn-130, two neutrons and another nucleus

Nuclear Reactions The alpha emission forming Pa-233 The fusion of two C-12 nuclei to give Na- 23 and another particle

Nuclear Reactions Bombard U-238 with a nucleus to produce Fm-249 and five neutrons Bombard Al-27 with deuterium to produce and alpha particle and another nucleus

Nuclear Reactions U n  _____ n + ______ Rubidium-81 undergoes K-capture

Formula from Analysis 37A on p. 71

Combustion Analysis When any hydrocarbon burns, the same products are always made: CO 2 + H 2 O All of the carbon from the hydrocarbon turns into carbon dioxide. All of the hydrogen in the hydrocarbon turns into water. The amount of oxygen is from 2 sources.

Combustion Analysis P. 71 #39

Combustion Analysis If the hydrocarbon has other elements in it, the analysis of the other products will be given to you. #41 p. 72 #43 p. 72

MM determination An unknown gas collected in a 1-liter flask at 25 o C and 191 kPa has a mass of 2.63 g. What is the molar mass of the gas? What is the molar mass of a solute if 50.0 g dissolved into one-liter of solution at 15 o C has an osmotic pressure of 3.45 atm?

MM determination When 15.0 g of an unknown nonelectrolyte is dissolved in 250 mL of acetic acid, the freezing point is o C. What is the molar mass of the solute? P. 278 #39,41,43

Molecular Mass Determinations Using Colligative Properties At a certain temperature, the vapor pressure of benzene is atm. A solution prepared by dissolving 10.0 g of a molecular, nonvolatile solute in g benzene at that temperature has a vapor pressure of atm. Determine the MM of the solute. A g sample of a large biomolecule was dissolved in 15.0 g chloroform and the freezing point depression was 0.24 o C. Determine the MM of the molecule if Kf chloroform is An aqueous solution of 10.0 g catalase dissolved to make 1L of solution at 27 o C has an osmotic pressure of torr. Determine the MM of catalase (an enzyme found in liver).