Polarimeters are so sensitive that they can measure
rotationsto the thousandth of a degree, an important advantage when
onlysmall amounts of a sample are available. for example, when
7.00mgof ecdysone, an insect hormone that controls molting in
thesilkworm moth, was dissolved in 1.00 ml of choloroform in a
cellwith a 2.00 cm path length, an observed rotation
of+0.087o was found. calculate [a]d
forecdysone.

Explanation:

The equation to calculate the specific rotation () of a substance is:

Where:

In this case:

The specific rotation:

in cartography, a contour line (often just called a "contour") joins points of equal elevation (height) above a given level, such as mean sea level. a contour map is a map illustrated with contour lines, for example a topographic map, which thus shows valleys and hills, and the steepness or gentleness of slopes.

explanation: