An aqueous solution containing 4.95 g of an optically pure compound was diluted to 700.0 mL with water and placed in a polarimeter tube 15.0 cm long. The measured rotation was –3.65° at 25 °C. Calculate the specific rotation of the compound.

[∝] = 344.1°

Explanation:

The formula of specific rotation is:

[∝] = ∝ / c×l

Where [∝] is specific rotation, ∝ is measured rotation, c is concentration is g/mL and l is path length in decameters

Concentration is:

4.95g/700.0mL = 7.071x10⁻³ g/mL

Path length is:

15.0cm ₓ (1dm / 10cm = 1.50dm

Replacing:

[∝] = -3.65° / 7.071x10⁻³ g/mL×1.50dm

[∝] = 344.1°

I hope it helps!

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.