Presentation on theme: "A 1000 watt iron produces 1000 joules (1 kilojoule) of energy per second. How many kilocalories of energy is generated in one hour? (1 calorie=4.184 joules)"— Presentation transcript:
A 1000 watt iron produces 1000 joules (1 kilojoule) of energy per second. How many kilocalories of energy is generated in one hour? (1 calorie=4.184 joules) –1000 joules|1 cal | kilo |60 sec|60 min= 860 kcal sec |4.184 J| 1000 |1 min |1 hr How many atoms of chlorine is in dinitrogen tetrachloride? What volume of oil will have the same mass at 51 mL of mercury? (oil density= 0.90 g/mL, mercury density=13.6 g/mL) –51 mL |13.6 g =693.6 g g |1 mL = 771mL | mL |0.90g Study guide for Part 1 of Final Exam
Know acid names and formulas: Hydrochloric acid, Nitric acid, Nitrous acid, Sulfuric acid, sulfurous acid, Phosphoric acid Physical change versus chemical change –Physical change is a change from solid to liquid or a liquid to gas. –A chemical change is coming apart or combining with other elements or compounds. Burning, rusting, decomposing, reacting with other compounds are examples.
Precision versus accuracy –If your measurements are close to each other, you have precision. If they match a known or expected value, then you have accuracy. Know pure element, compound, and mixture. –An element is made of just one kind of atom. O2 is and element even though there are two of them together. –A compound is two or more elements combined. Visually you would see two different atoms (spheres) joined. – A mixture are two or more compounds mixed but not bonded together. Visually, you would see more than one kind of atom or molecule separate from each other. OO CO CONN
Know charge on polyatomic ions like chlorates, sulfates, carbonates, phosphates Know a precipitation reaction –NaCl(aq) + AgNO 3 (aq) AgCl(s) + NaNO 3(aq)
What is produced when alkali metals or alkaline earth metals are placed in water. Na + H 2 O or write 2Na(s) + 2HOH (l) 2NaOH (aq) + H 2(g) What is difference between total ionic equation and net ionic equation? –Top is total ionic, bottom is net ionic –Na + (aq) + Cl - (aq) + Ag + (aq) + NO 3 - (aq) AgCl(s) + Na + (aq) + NO 3 - (aq) –Cl - (aq) + Ag + (aq) AgCl (s)
Figuring oxidation number of metals combined with non-metals such as 6A, & 7A non-metals. CuS, TiF 4, TiO 2, MnO 4 -. –Always start with the oxidation number of the non- metal. Sulfur and oxygen are -2. –Copper is 2+, Ti is 4+ for both, and Mn is +7. What would neutralize acids? Hydroxides (OH-) or carbonates (CO 3 2- ). Solubility rules. –Sulfates are soluble except for barium and lead. Chlorides, bromides, and fluorides are soluble except for silver, lead, and mercury.
Given moles of one compound in a reaction, give moles of the others. –2KClO 3 2KCl + 3O 2 –0.245 moles O 2 |2 mol KClO 3 = moles KClO 3 |3 mol O 2 Discern excess or insufficient quantities in a reaction. –2Al + 3Cl 2 2AlCl 3 (57 g Al & 200g of Cl), which reactant has an excess and how much? –54 g Al |1 mol= 2.1 mol Al |27 g –200 g Cl|1 mol = 5.6 mol Cl or 2.8 mole Cl 2 |35.6 g –2.1 mol Al | 3 mol Cl2 = 3.15 mol Cl 2 | 2 mole Al –2.8 mol Cl 2 | 2 mol Al = 1.87 mol Al | 3 mole Cl 2 –2.8 moles of Cl2 can is only enough to react with 1.87 mol Al. Since there are 2.1 moles of Al, there is 0.23 ( ) moles of Al in excess. For grams thats 0.23 mol x 27g/mole = 6.2 grams.
Figure % yield –12 grams of calcium chloride is reacted with an excess of sodium carbonate to make 9.5 grams of calcium carbonate. What was the % yield? –CaCl 2(aq) + Na 2 CO 3(aq) CaCO 3(s) + NaCl (aq) –12 g CaCl 2 | 1 mol = 0.11 mol CaCl 2 | 111 g –9.5 g CaCO 3 | 1 mol = mol CaCO 3 | 100 g –0.11 mol CaCl 2 should produce 0.11 mole of CaCO 3 however, it only produced moles. So the fraction of what it did produced over what it should have is 0.095/0.11 = 86% yield. –Equipment to make up a specific molar solution. –Moles per Liter. To find moles we need a balance. To measure liter accurately, we use a buret or a volumetric flask. But to make molar concentratons, a compound is placed in some water and the level brought up to one liter. So a volumetric flask is the best. Evidence of reactions (heat, precipitate, gas, color change)
Percent mass of one element in a compound –KMnO 4, --- What is percent mass of manganese? –K = 39 g/mol, KMnO 4 = 158 g/mol. % = 39/158 = 0.25 or 25% Balance a combustion reaction. C 5 H 8 O 3 + O 2 CO 2 + H 2 O –Balance carbons with CO 2 first, and hydrogen with water. Do O 2 last. Basic dilution problem. –Conc x Vol =Conc x Vol –Concentrated = Diluted How many mL of 2.5 molar solution of HCl is needed to make up 350 mL of 0.1M HCl? –Concentrated = Diluted –2.5 M x ?mL = 0.1M x 350 mL –Divide both sides by 2.5M to have mL= 0.1Mx350mL/2.5M –?mL = 14 mL
Moles of one element in a compound, knowing the compounds mass and formula. –24 grams Na 2 SO 4, how many moles of sulfur is there? –24 g Na 2 SO 4 | 1 mol = mol Na 2 SO 4 | 142 g –Since theres one sulfur in sodium sulfate, then the moles of sulfur is the same as the sodium sulfate. Knowing energetic light has shorter wavelength and higher frequency. Radio waves, infrared, visible light, ultraviolet, x-rays, gamma rays. Which has the shortest wavelength, which has highest frequency? Gammas rays are the shortest wavelength and the highest freqeuncy.
Heat of formation: page 244, 242 Bond energies: page 341 for table, page 349 for problem. Electron configuration page 301, 302