Practice Test Chemical Bonds and Compounds 1. Use electronegativity values to determine if the bonds formed between each of the following atoms would be ionic, covalent, or polar covalent Ni & Cl _____ Br & S _____ F & P _____ S & Ba _____ O & P _____ Fe & F _____ I & C _____ Mg & O _____ 2. 15. What is Avagadro’s Number? 16. What is the formula weight of Carbon SiO2 Mg(NO3)2 Na2S 17. What is the mass of 3 moles of Calcium 7 moles of CO2 5.44 1025 atoms of Silver (Ag) 3.68 1022 molecules of NCl3 18. How many moles are there in 148g of gold 178g of CaCl2 67g of (NH4)2S 19. How many Atoms of Fluorine are there in 4 moles of CF4? _______________ How many Moles of Oxygen are there in 4 moles of Al(NO3)3? _______________ How many atoms of Oxygen are there in 4 moles of Al(NO3)3? _______________ How many grams of Oxygen are there in 245g of CO2? __________________ 20. For each of the following molecules, determine if the bonds are covalent or polar covalent. Next, determine if it is a polar molecule, write “yes” if it is, and “no” if it is not. Compound SiO2 NF3 SO2 molecular shape (linear) (trigonal pyramidal) (bent) bond type polar molecule (Y/N) _______________ _______________ _______________ _______________ _______________ _______________ CH4 (tetrahedral) _______________ _______________ SO3 (trigonal planar) _______________ _______________ 21. Air is a mixture of roughly 80% N2, and 20% O2 which element is the solvent? 22. Which of the following compounds would you expect to be soluble in SBr 2 (a bent molecule)? (hint: look at the electronegativity values) H2O SeBr2 SF2 NF3 23. How many moles of H2SO4 are there in 400 ml of a 6 M solution? 24. How many grams of BaCl2 are there in 250 ml of a 7.4 M solution? 25. How many Chloride ions are there in 150 ml of a 0.06M solution of AlCl 3? 26. How many ml of 6.0 M NaCl solution would you need in order to prepare 125 ml of 0.5 M NaCl solution? (look at the graph above to answer questions 27 – 29) 27. How many grams of Calcium Chloride can be dissolved in 100 g of water at 20C? 28. How hot would the water have to be in order to get 70g of K 2Cr2O7 to dissolve in 100g of water? 29. If a 60g crystal of Pb(NO3)2 was put in 100g of water at 20C, how much of the crystal would be left after it dissolved? Answers to Practice Test Chemical Bonds and Compounds 1. an element has only one kind of atom, a compound is made of two or more different kinds of atoms 2. an ionic compound is formed between a metal and a non-metal and involves electrons leaving the metal atom and joining the non-metal atom. A covalent compound involves two non-metals that share electrons. 3. In a solution the largest particle is an atom, molecule, or ion 4. metal 5. ionic compound 6. noble gas 7. covalent bond 8. ionic bond 9. O2 and Ca 10. Al & O ionic F & Ne none Ni & Cr no N & I covalent C & Cl covalent Pb & S inoic Ar & S none Na & P ionic 11. sodium oxide ammonium sulfide 12. Cu3PO4 13. dinitrogen hexaoxide silicon dioxide P2O5 MgF2 Ni & Cl polar covalent O & P polar covalent lead(II)hydroxide iron (II) sulfate Cr(ClO2)6 Fe2O3 Br & S covalent Fe & F ionic NBr3 F & P ionic I & C covalent S & Ba polar covalent Mg & O ionic 14. 15. 6.02 1023 16. C: 12.011 SiO2: 60.065 Mg(NO3)2 :148.24 Na2S: 78.044 17. 120.234 307.937 9747.558 7.357 18. gold: 0.75 moles CaCl2: 1.60 moles (NH4)2S: 0.98 moles 19. CF4: 9.63 1024 Al(NO3)3: 36 moles Al(NO3)3: 2.17 1025 atoms CO2: 178.13 g 20. SiO2 polar, no CH4 covalent, no NF3 polar, yes SO3 Polar, no SO2 polar, yes 21. N2 because there is more of it 22. SeBr2 because it is non-polar and so is SBr2 23. 2.4 moles 24. 385.23 g 25. 1.6 1022 26. 10.4 ml 27. 75g 28. 90C 29 5g