Presentation on theme: "AP C HEMISTRY - R EVIEW Review1. U NCERTAINTIES R EVIEW As part of your Lab Group. Analyze the following data. Mass of beaker:7.15 g +/- 0.01 g Mass of."— Presentation transcript:
U NCERTAINTIES R EVIEW 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/cm 3 Find the % error and Discuss which type of error is more significant.
C ONVERSIONS A mole of anything is equal to 6.02 x10 23 1 mole of an element is equal to its molar mass. So 1 mole of Carbon = 12g of C= 6.02x10 23 atoms of C Convert 875 grams of C to atoms of carbon? Convert 3.156x10 22 atoms of C to grams of C?
M OLAR M ASS 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 Ca 3 (PO 4 ) 2 3 (Ca) + 2(P) + 8 (O) 3 (40) + 2 (31) + 8 (16) 120 + 62 + 128 = 310 g
C OVALENT C OMPOUNDS Covalent compounds exist as molecules. They are made up of nonmetals atoms. Water: H 2 O 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 x10 23 molecules and each molecule contains 3 atoms. Two of hydrogen and one of oxygen. Calculate the number of molecules in 45 grams of C 2 H 6
C OVALENT N OMENCLATURE 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= mono2= di3= tri4= tetra5= penta 6= hexa7= hepta8= octa9= nona10= deca The prefix mono is not usually used for the first element. Carbon Dioxide= CO 2 Disulfur Dichloride= S 2 Cl 2 Dichlorine tetraoxide = ?
I ONIC 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 x10 23 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 CaCl 2
P OLYATOMIC I ONS NitrateNO 3 -1 PhosphatePO 4 -3 AcetateC 2 H 3 O 2 -1 SulfateSO 4 -2 CarbonateCO 3 -2 ChlorateClO 3 -1 AmmoniumNH 4 +1 HydroxideOH -1 CyanideCN -1 PeroxideO 2 -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
I ONIC F ORMULAS Find the charges of each ion, cross them and reduce if possible Aluminum NitrideAl +3 N -3 Al 3 N 3 AlN Sodium PhosphateNa +1 PO 4 -3 Na 3 PO 4 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 IVIron II, Iron IIITin II, IV Many of the transitional metals have multiple charges. The ones above, you MUST know. Zinc is always +2, Silver is always +1
A SSIGNMENT 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 x10 18 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 acetateF) Disilicon trioxide B) Zinc SulfideG) Lead IV Chromate C) Dinitrogen hexaoxideH) Magnesium peroxide D) Iron III PerphosphateI) Calcium Hypochlorite E) Silver nitrateJ) Sulfur Dioxide