NYSTCE ATAS NYSTCE Chemistry 5

Question 1

Which of the following correctly describes isotopes of the same element?

Accepted Answer

Same number of protons, different number of neutrons

Answer

Isotopes of an element have the same atomic number (protons) but differ in the number of neutrons, giving them different mass numbers.

Question 2

Which of the following is an example of a homogeneous mixture?

Accepted Answer

Salt dissolved in water

Answer

Salt dissolved in water forms a homogeneous mixture (solution) because the composition is uniform throughout the liquid.

Question 3

In a single replacement reaction such as Zn + 2HCl → ZnCl₂ + H₂, zinc replaces hydrogen because:

Accepted Answer

Zinc is more reactive than hydrogen in the activity series

Answer

In the activity series, zinc is above hydrogen, meaning it is more reactive and can displace hydrogen from acid solutions.

Question 4

Which state of matter has a definite volume but takes the shape of its container?

Accepted Answer

Liquid

Answer

Liquids have a fixed volume because their particles are close together, but they flow to take the shape of any container.

Question 5

The Avogadro's number (6.02 × 10²³) represents the number of particles in:

Accepted Answer

One mole of a substance

Answer

Avogadro's number defines the mole: one mole of any substance contains 6.02 × 10²³ representative particles (atoms, molecules, or formula units).

NYSTCE ATAS - NYSTCE Assessment of Teaching Assistant Skills Practice Test