Ch 1-5 to 1-6 Significant Figures pp 22-37 Know how significant digits are found and used in calculations. Ch 1-6 Working With Numbers; Scientific Notation pp 30-32 Know how to use the calculator exponent button to complete dimensional analysis problems. Memorize: 1.0 x 10 9 nm = 1 m Ch 1-6 Percents & Percent Error pg 33 Calculate percent error by using data &/or given numbers. % error = experimental value accepted value x 100% accepted value 500 nm to m (color of blue) 3.4 m to nm (FM radiowave)
Ch 4-1 Radiant Energy pp 125-129 Know the major regions of the electromagnetic spectrum, to calculate frequency, wavelength, & speed of light. Frequency (v) = c = speed of light (3 x 10 8 m/s) wavelength 15.2 Concentration of Solutions pg 508 1000 g = 1 kg Molality (m) = moles of solute = mol Kg of solvent kg What is the molality of a solution containing 75.2 g of AgClO 4 dissolved in 885 g of benzene? What s the frequency of a wavelength of light of 500 nm? What is the molality of a solid solution of 0.125 g Cr & 81.3 g of Fe? The frequency of a red light is 4.74 x 10 14 calculate its wavelength. Sec Ch 10-1 Molar Mass pp 320-321 To define molar mass (amu) & calculate amu Ch 15.2 Concentration of Solutions pp 506-507 1000 ml = 1 L Molarity (M) = moles of solute = mol Liters of solution L To find the molarity of a solution 8.320g NiCl2 added to 250 ml of water, what s the concentration? How many grams of KCl are needed to prepare 0.750 L of a 1.50 M solution of KCl For example: NH 3 has the following amu: N = 1 atom x 14.01 amu = 14.01 amu H = 3 atoms x 1.01 amu = 3.03 amu total amu = 17.04 amu or 17.04 molar mass Calculate the molar mass (amu) of the compound: NaCl, table salt
Calculate the molar mass (amu) of the compound: Mg(SO4) 2, Epsom salt To find the percent composition by using the masses of each element in a compound Ch 10-3 Percent Composition of Compounds pp 332-334 To find the mass percent of an element in a given compound Percent composition can be determined of each element in a compound by its mass: % Composition = part mass x 100% or Mass % = mass solute x 100% whole mass mass solution This formula can be applied by using the formula of the compound or by experimental mass analysis of the compound (solution) % Composition = part x 100% whole N = 1 atom x 14.01 amu = 14.01 x 100% 17.03 = 82.21 % N H = 3 atoms x 1.01 amu = 3.03 x 100% 17.03 = 17.79 % H Find the percentage composition of a compound that contains 1.94 g of carbon, 0.48 g of hydrogen, and 2.58 g of sulfur in a 5.00 g sample of the solid solution. Calculate the percent by mass of each element in the compound: NaCl, table salt Find the percentage composition of a compound that contains 2.63 g of carbon, 0.370 g of hydrogen, and 0.580 g of oxygen in a 3.58 g sample of the gaseous solution. Calculate the percent by mass of each element in the compound: Mg(SO4)2, Epsom salt
Ch 10-1-10-2 The Mole Convert from g to mole to particles (back & forth), if needed use your mole map Ch 10-3 Empirical & Molecular Formulas Use percentage composition to determine the formula of an unknown sample, find empirical and molecular formulas. Molar mass = g 1 mole = 1 amu To Determine Empirical Formulas: 1. % is the same as grams 2. Convert from grams to moles 3. Next divide by the smallest # of moles 4. this gives the empirical formula Eugenol oil: is 73.14% C, 7.37% H and 19.49 g O Remember, % is the same as grams (g). Determine its empirical formula. A student weighs out 88 grams of solid CO 2 (dry ice), how many moles does the student have? Molecular Formula = True amu empirical amu Determine the true molecular formula for eugenol oil, using the above formula. Now convert to particles, in this case molecules.
Ch 7-3 & 14-3 Hydrated Crystals Name hydrated crystals. Determine empirical formula by using dehydrated salt crystal laboratory data. To name hydrates: 1. Name the compound 2. Plus the word hydrate use prefixes to indicate how many waters are associated with the compound 3. Example: Copper (II) Sulfate pentahydrate 4. To write their formulas Write: the name of the compound number of H 2 O CuSO 4 5 H 2 O Ch 11 Stoichiometry Relate stoichiometry to balanced chemical equations. Solve molemole problems, mass-mass problems. Determine limiting reactants & Percent Yield Ch 11-1 Mole-Mole Stoichiometry A student heats hydrated crystals of CuSO 4, how many moles of water are associated with the crystals? Step 1: Find the mass of the crystals: Step 2: Subtract the dehydrated crystal mass from the initial crystal mass = mass of water Step 3: Determine the number of moles Step 4: Determine the molar ratio (see above) Mass of hydrated crystal: 1.023 g of CuSO 4 x H 2 O Mass of dehydrated crystal: 0.654 g of CuSO 4 N 2 + 3 H 2 2 NH 3 How many moles of NH 3 can be made from 1.30 mol H 2?
Ch 11-2 Mass-Mass Stoichiometry 25,000 g of nitrogen gas and 5000 g of hydrogen gas are mixed and reacted to form ammonia. Remember, the limiting reactant determines the amount of product formed N 2 (g) + 3 H 2 (g) 2 NH 3 (g) 25,000 g 5,000 g? g What mass of gaseous carbon dioxide can 1000 g of lithium hydroxide absorb? 2 LiOH + CO 2 1000 g? g Ch 11-3 Limiting Reactants & Percent Yield Li CO + H O 2 3 2 To Determine Limiting Reactant: 1. Compare the moles of reactant 1 to reactant 2 2. This will determine how many moles needed for reactant 2 3. Then determine how many moles you actually have for reactant 2 4. Compare the moles of needed to actual 5. This will help you to determine what is limiting and what is excess