In Purdue's Chemistry department, the chemists have found that in a water based solution containing 1616 grams of certain undissolved chemicals, the rate of change of the amount of chemicals dissolved in the solution is proportional to the amount of the undissolved chemicals. Let Q(t)Q(t) (in grams) be the amount of dissolved chemicals at time tt and let kk be the positive proportionality constant. The differential equation describing the given situation is:

The differential equation describing the given situation is dQ/dt = k( 16 - Q )

Explanation:

Given the data in the question;

Initially, the water based solution contains 16 grams of undissolved chemicals;

Assume Q(t) is the amount of dissolved chemical at time L

then the amount of undissolved chemicals at time t is ( 16 - Q)

The rate of change of amount of chemicals dissolved in the solution is proportional to the amount of undissolved chemicals

this means;

dQ/dt ∝ ( 16 - Q)

dQ/dt = k( 16 - Q )

where k is the positive proportionality constant.

Therefore, The differential equation describing the given situation is dQ/dt = k( 16 - Q )

answer is: naturally occurring solid, inorganic compound or element is mineral.

minerals usually have crystalline form, that means than crystal constituents (atoms, molecules or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions.

for example magnetite is a mineral of iron oxide (fe₂o₃).

calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (caco₃).

dolomite is an   carbonate mineral composed of calcium magnesium carbonate (camg(co₃)₂).

the answer is b because, investigating whether another species of moth also drinks tears might be interesting, but it would not directly explain why this species of moth does.

to explain why this species of moth drinks tears, the scientist could ask: "what nutrients that moths need are in elephant tears? "

the scientist could experiment with moth repellent or oter ways to keep the moths away, but that would not answer his original question.