A Student Measured the Optical Activity of an Unknown Sugar

question 63

Multiple Choice

A student measured the optical activity of an unknown sugar at two different concentrations. The results of his measurements are shown below. Given that the sample cell had a path length of 10.0 cm, calculate the specific rotation for the unknown sugar. (Hint: Consider each measurement of plane polarized light has a true reading and a "ghost" reading 180° from the true reading) .
Concentration observed rotation
2) 00 g sugar in 10.0 mL water +159.1°
5) 00 g sugar in 10.0 mL water +127.8°

• A) -10.5°
• B) +25.6°
• C) +79.5°
• D) -105°
• E) +256°

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Definitions:

Fluid intelligence

The ability to think logically and solve problems in novel situations, independent of acquired knowledge.

Prospective memory

The aspect of memory that involves remembering to perform a planned action or intention at the appropriate time.

Retrospective memory

The ability to remember information and events from the past, including facts, experiences, and people.

Cross-linking theory

A theory in biology and chemistry describing how chemical bonds form between different parts of a molecule or between molecules, affecting properties like elasticity in tissues.