Other Topics

153. (Nuclear chemistry) To balance the equation ²³⁰Th --> ⁴He + ²²⁶
the other element produced is

Ra, Rn, Po

154. (Logarithms, nuclear chemistry, half-lives) Demonstration: Pass out semilog paper and have students plot the following data for decay of a Tc isotope. What is the approximate half life in hours?

4, 6, 8

173. Demonstration: Draw or obtain a rectangle. Measure one side of the rectangle carefully to 3 significant figures, and measure the other side of the rectangle to only 1 significant figure. Ask the class what the area of the rectangle is based on your measurements.

What is the area of a rectangle that is 3 m by 1.11 m?

3.33 m², 3 m²

174. The following columns of substances are listed as a combination of pure substances and mixtures. Which column represents mostly pure substances and which mostly mixtures?

column A is mostly pure substances and column B is mostly mixtures
column A is mostly mixtures and column B is mostly pure substances

Which substances are in the wrong column?

milk, graphite, raisin bran, gold

185. Which of the flasks below will contain a mixture when all the hydrogen reacts with oxygen to give water?

Flask A, Flask B

194. For the amino acid glycine (H₂N-CH₂-CO₂H), the pKa of the -NH³⁺ group is about 10 and pKa of the -CO₂H group is about 2. At pH 0, what form of these groups is primarily present?

NH³⁺ and CO₂H, NH³⁺ and CO^2-, NH₂ and CO₂H, NH₂ and CO^2-

195. The pKa of the weak acid, HF, is about 3. The pKb of the weak base F- is about:

-11, 3, 11, 1

197. The molecule shown below contains which functional groups?

amide, amine, alcohol
ester, amide, ether
ester, amine, ether
carboxylic acid, amide, alcohol

How many hydrogens are present in the structure?

8, 9, 10, 11

207. Which particle is emitted in the following nuclear reaction?

A, B, C

208. What is the formula of bis(ethylenediamine)dichlorocobalt (III)?

A, B, C

215. Water droplets were recently made to perform the astonishing feat of climbing uphill against gravity on a coated microscope slide. To make this process occur, the slide would have to be coated in which of the following ways?

A. Uniformly coated with a polar film
B. Uniformly coated with a nonpolar film
C. Coated with a film that gradually increased in polarity from the bottom of the slide to the top
D. Coated with a film that gradually decreased in polarity from the bottom of the slide to the top

(Adapted from M. K. Chaudhury and G. M. Whitesides, Science, 256, 1539 (1992).)

227. Take a square refrigerator magnet and cut off a thin strip from both the horizontal and vertical edges. Place one of the thin magnetic strips on the back of the large magnet as shown below and pull gently vertically and then horizontally. Now try the other magnetic strip.

Which is the best representation of the magnetic field of the large magnet, where N represents the north pole and S the south pole?

A, B, C

230. Ibuprofen is an anti-inflammatory drug also used as an aspirin substitute.

Ibuprofen

To what family of organic compounds does ibuprofen belong?

A. Aldehyde
B. Acid
C. Alcohol

What alkyl group is attached to the para position of the benzene ring of the ibuprofen molecule?

A. n-butyl
B. isobutyl
C. sec-butyl
D. tert-butyl

232. Procaine, a local anesthetic whose hydrochloride salt is Novocain, has the following structure:

Procaine

Identify the functional groups:

A. ester or amide
B. primary, secondary, tertiary amine

More questions are needed for this section. Please submit contributions to concept@chem.wisc.edu..