FE Chemical Mathematics Practice Problems

The current FE Chemical specification assigns 6-9 of the 110 exam questions to Mathematics. Form A contains 7 original problems in this area. The sample below is published in full, with the same worked-solution format used throughout the book.

Free sample problem

A concentration follows $ln C = 1.20 - 0.035 t$ , with t in minutes. The time when C=2.0 is most nearly:

(A)14.5 min
(B)18 min
(C)24 min
(D)34 min

Show worked solution

Answer: (A)

Solving $ln 2 = 1.20 - 0.035 t$ gives t=14.5 min.

The target concentration fixes the left side of the linear logarithmic model.

0.6931 = 1.20 - 0.035 t

Isolating time gives the crossing point.

t = (1.20 - 0.6931) /0.035 = 14.5 min

FE Reference Handbook — Mathematics: Logarithms

Why the other choices appear

(B)Using base-10 logarithm in place of the stated natural logarithm overstates time.
(C)Dropping the intercept before solving gives an unsupported value.
(D)Dividing the intercept alone by the decay coefficient ignores the target concentration.

The complete FE Chemical practice exam contains 7 problems in this area and 110 problems overall, with an answer key, full solutions, and a score sheet by knowledge area.

Free FE Chemical problems in the other knowledge areas

Probability and Statistics · Engineering Sciences · Materials Science · Chemistry and Biology · Fluid Mechanics and Dynamics · Thermodynamics · Material and Energy Balances · Heat Transfer · Mass Transfer and Separation · Solids Handling · Chemical Reaction Engineering · Economics · Process Design · Process Control · Safety, Health, and Environment · Ethics and Professional Practice

Retaking this exam? The FE exam retake guide turns the NCEES diagnostic report into an area-by-area plan.