REVIEW QUESTIONS Chapter 3

Transcription

1 Chemistry 101 ANSWER KEY REVIEW QUESTIONS Chapter 3 1. Using only a periodic table, assign charges for each ion below, then complete the table with formulas and names for compounds formed by the combination of each cation and anion. Ca + K 1+ Al 3+ NH4 1+ S Cl 1 N 3 NO 1 SO4 NO3 1 CO3 ClO3 1 OH 1 PO4 3 CaS KS AlS3 (NH4)S CaCl KCl AlCl3 NH4Cl Ca3N K3N AlN (NH4)3N Ca(NO) KNO Al(NO)3 NH4NO CaSO4 KSO4 Al(SO4)3 (NH4)SO4 Ca(NO3) KNO3 Al(NO3)3 NH4NO3 CaCO3 KCO3 Al(CO3)3 (NH4)CO3 Ca(ClO3) KClO3 Al(ClO3)3 NH4ClO3 Ca(OH) KOH Al(OH)3 NH4OH Ca3(PO4) K3PO4 AlPO4 (NH4)3PO4 1

2 . Fill in the missing name or formula for each compound listed below. Fill in column 1 without using any notes, and then fill in column with the use of notes. 1 Barium Ferrous Silver Strontium Copper(II) acetate Zinc sulfite Iodine heptafluoride Bromine trifluoride CuClO4 AgSO4 NO5 HgI PbO OF Ba(NO3) FeCl AgOH Sr3(PO4) Cu(CH3O) Zn(NO) KSO3 (NH4)CO3 IF7 BrF3 copper(i) per silver dinitrogen pentoxide mercury(i) iodide lead (IV) oxide oxygen difluoride

3 3. For each compound shown below, determine if the name or formula is incorrect, and write the correct form in the space provided: a) AgS Disilver Silver b) MgOH Magnesium Mg(OH) c) Ca(NO3) (II) d) SnO Tin (II) oxide Tin (IV) oxide e) PbS Lead Lead (II) f) ZnCl Zinc di Zinc g) SO Sodium dioxide Sulfur dioxide h) CaSO4 i) BaO Barium oxide BaO j) CuO Copper (II) oxide Copper (I) oxide 4. Balance the following equations by providing the missing coefficients: a) 1 NH4NO3 1 NO + HO b) 1 Mg3N + 6 HO 3 Mg(OH) + NH3 c) 1 NCl3 + 3 HO 1 NH3 + 3 HOCl d) C5H10O + 13 O 10 CO + 10 HO e) 1 (NH4)CrO7 1 N + 1 CrO3 + 4 HO f) 1 PCl5 + 4 HO 1 H3PO4 + 5 HCl 3

4 5. Write a balanced equation for each reaction described below. Include state designations: a) When an aqueous solution of potassium dichromate is added to and aqueous solution of lead(ii), solid lead(ii) dichromate and aqueous potassium are formed. KCrO7 (aq) + Pb(NO3) (aq) PbCrO7 (s) + KNO3 (aq) b) When chlorine gas is bubbled though an aqueous solution of potassium bromide, bromine gas and aqueous potassium are formed. Cl (g) + KBr (aq) Br (g) + KCl (aq) c) When zinc metal is reaction with aqueous nitric acid, the reaction produces nitrogen gas, water and aqueous zinc. 5 Zn (s) + 1 HNO3 (aq) N (g) + 6 HO (l) + 5 Zn(NO3) (aq) 6. What mass of chlorine is present in 1. g of PbCl? 1. g PbCl x 78.1 g Cl x 1 PbCl g x = 3.11 g 7. How many atoms of oxygen are present in.15 g of Ca3(PO4)?.15 g Ca 3(PO 4) 3 8 O 6.0x10 atoms x x x = 3.34x10 O atoms g 1 Ca 3 (PO 4 ) 4

5 8. What is the percent composition of caffeine (C8H10N4O)? molar mass = 194. g/mol 8 x x % C = x100 = 49.47% % N = x100 = 8.85% x 1.01 x % H = x100 = 5.0% % O = x100 = 16.48% Determine the empirical formula for a compound with the following composition: 6.1% C 5.1% H 1.1% N 0.7% O mol C = 6.1 g mol H = 5.1 g mol N = 1.1 g x 1.01 g x = 5.17 (6) (1) x 1.01 g x = 5.16 (6) (1) x g x = (1) () mol O = 0.7 g x x = 1.9 (1.5) (3) g Empirical formula = C H N O Combustion analysis of a 1.01-g sample of an unknown acid which contains only carbon, hydrogen and oxygen produced g CO and 4.3 g HO. Determine the empirical formula for this acid g CO C x x g CO = 0.30 mol C = 3.84 g C 4.3 g HO mol H x x = mol H =0.485 g H 18.0 g H O Mass of O = 1.01 g -(3.84 g g) =7.685 g O g O mol ratio = (C H O ) Empirical formula = C H O 3 3 x g = mol O 5

6 11. A phosphorous compound that contains 34.00% phosphorus by mass has the formula X3P. Identify the element X. Assuming 100 g of sample, g P x g 3 mol X x mol P = mol X g molar mass of X = = g/mol X is calcium (Ca) mol 1. A 3.41-g sample of a hydrate of copper(ii) was heated to drive off the water of hydration. The anhydrous salt was found to have a mass of.69 g. Determine the formula for this hydrate. mass of water = 3.41 g -.69 g = 0.7 g.69 g CuCl x = mol (1) g 0.7 g HO x = mol () 18.0 g formula of hydrate = CuCl H O 13. Classify each hydrocarbon below as alkane, alkene or alkyne, and write a molecular formula for each: a) c) alkene (C4H8) alkane (C4H10) b) d) Alkyne (C4H6) alkene (C6H1) 6