ACSBR 20B Molecular Structures (Extensions) - Assignment ANS

Anglo-Chinese School (Barker Road) A Methodist Institution Founded in 1886 CHEMISTRY DEPARTMENT OF SCIENCE Name: ANSWERS ( ) Class: SEC 4 OC: MOLECULAR STRUCTURES (EXTENSIONS) – ASSIGNMENT ALEX LEE/2010 PAGE 1 OF 6 PURE Multiple-Choice Questions [20 Marks] TOTAL SCORE / 30 Write in your selected answer for the multiple-choice questions in the boxes provided. 1 2 3 4 5 6 7 8 9 10 B A B C A B C C A D 11 12 13 14 15 16 17 18 19 20 C A D A A B B C C C 1. Which of the following statements about isomers is false? A Isomers have the same relative molecular mass. B Isomers have the same strength of intermolecular forces. C Isomers may have the same chemical properties as each other. D Isomers have the same percentage composition of elements. 2. Two molecules are isomers. It follows that these two molecules A contain the same elements. C have different molecular formulae. B contain the same functional group. D have the same structural formula. 3. Butanoic acid has a formula C4H8O2. It can be concluded that an isomer of this molecule A must be able to react with carbonates. B must combust to form carbon dioxide and water. C must contain the –COOH functional group. D must not contain a C=C bond in its structure. 4. What property do methylpropane and butane not have in common? A combustion products B empirical formula C melting and boiling points D relative molecular mass 5. The smallest alkane to have more than one structural isomer is A butane B ethane C pentane D propane

ALEX LEE/2010 PAGE 2 OF 6 6. How many structural isomers exist for C2H6O? A one B two C three D four 7. Which of the following molecules have the greatest number of structural isomers? A C3H7Cl B C3H6Cl2 C C3H4Cl4 D C3H2Cl6 8. A compound with the formula C4H9F has A 2 isomers. B 3 isomers. C 4 isomers. D 5 isomers. 9. Which, of the four molecules below, is a different structure from the other three molecules? A C B D 10. Which of the following pairs of molecules are not isomers? A and B and C and D and C C Cl Cl H H H Cl C C H H Cl Cl Cl H C C Cl H Cl Cl H H C C H Cl Cl H Cl H C C C H Cl H Cl H H H H C C C H H Cl H H H Cl H C C C H H Cl H H Cl H H C C C H H H Cl H H Cl H C C C Cl H H Cl H H H H C C C H H Cl H Cl H H H C C C H H Cl Cl H H H H C C C Cl H Cl H H H H H

ALEX LEE/2010 PAGE 3 OF 6 11. Three molecules, X, Y and Z, are shown below. molecule X molecule Y molecule Z Which of the following statements are true? A Molecules X and Y have different molecular formula. B Molecules X and Z are isomers of each other. C Molecules X and Z have the same structural formula. D Molecules Y and Z have the same melting and boiling points. 12. The structure of a chloroalkane P is shown below. molecule P Which of the molecules below are identical to P? A