MCAT (Chemical and Physical Foundations) 5

Question 1

A fluid flows through a pipe that narrows from a cross-sectional area of 0.04 m² to 0.01 m². If the velocity in the wide section is 2 m/s, what is the velocity in the narrow section?

Accepted Answer

8 m/s

Answer

By the continuity equation, A₁v₁ = A₂v₂: 0.04×2 = 0.01×v₂; v₂ = 8 m/s.

Question 2

Which of the following statements about Le Chatelier's principle is correct when pressure is increased on the equilibrium N₂(g) + 3H₂(g) ⇌ 2NH₃(g)?

Accepted Answer

Equilibrium shifts right to produce fewer moles of gas

Answer

Increasing pressure favors the side with fewer moles of gas; 4 moles of reactant gas form 2 moles of NH₃, so equilibrium shifts right.

Question 3

Which of the following correctly describes a diamagnetic species?

Accepted Answer

It contains only paired electrons and is weakly repelled by a magnetic field

Answer

Diamagnetic species have all electrons paired; they experience weak repulsion in a magnetic field because paired electrons cancel each other's magnetic moments.

Question 4

A converging lens with focal length 10 cm forms an image of an object placed 30 cm away. Where is the image located?

Accepted Answer

15 cm on the opposite side

Answer

Using 1/f = 1/do + 1/di: 1/10 = 1/30 + 1/di; di = 15 cm on the opposite side (real image).

Question 5

Which type of radioactive decay results in a product with the same mass number but a different atomic number?

Accepted Answer

Beta decay

Answer

Beta decay converts a neutron to a proton (or vice versa), changing Z by ±1 while mass number A remains constant.

MCAT - Medical College Admission Test Practice Test

MCAT - Medical College Admission Test Practice Test

MCAT (Chemical and Physical Foundations) 5