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AP Chemistry- Review. Review1. Uncertainties Review. As part of your Lab Group. Analyze the following data. Mass of beaker: 7.15 g +/- 0.01 g Mass of beaker + metal: 12.12g +/- 0.01 g Height of cube: 2.12 cm +/- 0.01 cm Width of cube: 1.05 cm +/- 0.01 cm
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AP Chemistry- Review Review1
Uncertainties Review • As part of your Lab Group. Analyze the following data. • Mass of beaker: 7.15 g +/- 0.01 g • Mass of beaker + metal: 12.12g +/- 0.01 g • Height of cube: 2.12 cm +/- 0.01 cm • Width of cube: 1.05 cm +/- 0.01 cm • Length of cube: 0.75 cm+/- 0.01 cm • Calculate the density of the cube with uncertainty. • Given the theoretical density as 2.65 g/cm3 Find the % error and Discuss which type of error is more significant.
Conversions • A mole of anything is equal to 6.02 x1023 • 1 mole of an element is equal to its molar mass. • So 1 mole of Carbon = 12g of C= 6.02x1023 atoms of C • Convert 875 grams of C to atoms of carbon? • Convert 3.156x1022 atoms of C to grams of C?
Molar Mass • Molar mass is the mass of one mole of an element or compound. • If its an element we can find the molar mass by looking at the atomic mass of that element. Example, N-14 g • If it’s a compound we must calculate it by multiplying the number of atoms times each atomic mass. • Example. Find the molar mass of Ca3(PO4)2 • 3 (Ca) + 2(P) + 8 (O) • 3 (40) + 2 (31) + 8 (16) • 120 + 62 + 128 = 310 g
Covalent Compounds • Covalent compounds exist as molecules. They are made up of nonmetals atoms. • Water: H2O is made up of atoms of hydrogen and oxygen, both nonmetals. So it’s a covalent compound and exists as molecules. • 1 mole of water = 6.02 x1023 molecules and each molecule contains 3 atoms. Two of hydrogen and one of oxygen. • Calculate the number of molecules in 45 grams of C2H6
Covalent Nomenclature • In naming covalent compounds , you must use prefixes to identify the number of each atom in the formula. You never reduce. First element keep its name, second ends in ide. • Prefixes: • 1= mono 2= di 3= tri 4= tetra 5= penta • 6= hexa 7= hepta 8= octa 9= nona 10= deca • The prefix mono is not usually used for the first element. • Carbon Dioxide= CO2 Disulfur Dichloride= S2Cl2 • Dichlorinetetraoxide = ?
Ionic compounds • These are compounds formed when metal atoms combined with nonmetal atoms or polyatomic ions. • What are polyatomic ions? • 1 mole of an ionic compound is equal to 6.02 x1023 Formula units. ( fu’s) • Sodium Chloride- NaCl- is an ionic compound and one mole of sodium chloride is equal to 6.02 x10 23 fu. Each fu is made up of two atoms, one of Na and one of Cl. • Calculate how many atoms are found in 285 grams of CaCl2
Polyatomic Ions • Nitrate NO3-1 Phosphate PO4-3 • Acetate C2H3O2-1 Sulfate SO4-2 • Carbonate CO3-2 Chlorate ClO3-1 • Ammonium NH4+1 Hydroxide OH-1 • Cyanide CN-1 Peroxide O2-1 • - ite ending = one oxygen less than ate • Hypo---ite= one oxygen less than ite • Per-----ate= one oxygen more than ate • What’s the formula for: • Hypochlorite • Persulfate
Ionic Formulas • Find the charges of each ion, cross them and reduce if possible • Aluminum Nitride Al+3 N-3 Al3N3AlN • Sodium Phosphate Na+1 PO4-3 Na3PO4 • Some metals like Copper have more than one charge, thus we use Roman numbers to identify them • Copper I = Cu+1 Copper II= Cu+2 • Lead II, Lead IV Iron II, Iron III Tin II, IV • Many of the transitional metals have multiple charges. The ones above, you MUST know. • Zinc is always +2, Silver is always +1
Assignment • 1. Convert the following: Show set up • A) 1.15 grams of gold to atoms • B) 2.85 grams of Aluminum oxide to atoms • C) 0.88 grams of Carbon Dioxide to molecules • D) 2.805 x1018 molecules of water to grams • E) How many formula units of Calcium Sulfite in 888 grams. 2. Write the formulas for the following compounds A) Copper I acetate F) Disilicon trioxide B) Zinc Sulfide G) Lead IV Chromate C) DinitrogenhexaoxideH) Magnesium peroxide D) Iron III PerphosphateI) Calcium Hypochlorite E) Silver nitrate J) Sulfur Dioxide