Chem 141 2009_Sample Exam 1 Solns

Chem 141 2009_Sample Exam 1 Solns - Chem 141 Sample Exam 1...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Chem 141 Sample Exam 1 Solutions 2009 Ia. Fe(s) > O 2 (g) > Fe 2 O 3 (s). The ranking is evident from the balanced equation given below. 4 Fe(s) + 3 O 2 (g) 2 Fe 2 O 3 (s) Ib. C-C > C-H > C-F. The ionic character of a bond between two atoms increases with the electronegativity difference between the atoms. Since electronegativity generally increases from left to right and from bottom to top on the periodic table, the relative ordering of electronegativities of the atoms in trifluoroethane is F > C > H, with C closer to H than to F. The least covalent ( i.e. , most ionic) bond is the one that corresponds to the largest electronegativity difference, C-F. The C-C bond is 100% covalent since there is no electronegativity difference, and the C-H bonds are highly covalent with only a very small amount of ionic character. Ic. C > Na > Pb. The number of atoms (expressed in units of moles) in 1.00 g of an elemental substance is given by: amu in mass atomic g 1.00 moles) (in atoms of no. = Since the number of atoms is inversely proportional to the atomic mass, the larger the atomic mass, the fewer the atoms in 1.00 g of the element. Thus 1.00 g of Pb, with the largest atomic mass (207.2 amu) of the three elements,
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 01/20/2011 for the course CHEM 141 taught by Professor Westmoreland during the Fall '09 term at Wesleyan.

Page1 / 4

Chem 141 2009_Sample Exam 1 Solns - Chem 141 Sample Exam 1...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online