FREE NYSTCE Chemistry Questions and Answers

Question 1

In general, how do atomic masses vary across the periodic table of elements?

Accepted Answer

They increase from left to right and top to bottom.

Answer

The periodic table is fundamentally organized by increasing atomic number, which generally correlates with increasing atomic mass. As you move from left to right across a period, the number of protons and neutrons increases, and similarly, moving down a group adds more electron shells and mass. This consistent trend results in atomic masses generally increasing from left to right and top to bottom.

Question 2

How many moles of carbon-12 are there in 6 grams of carbon-12?

Accepted Answer

0.5 mole

Answer

One mole of any element is defined as its atomic mass expressed in grams. For carbon-12, the atomic mass is 12 atomic mass units (amu), meaning one mole of carbon-12 weighs 12 grams. Therefore, 6 grams of carbon-12 represents exactly half of a mole (6g / 12g/mol = 0.5 mol).

Question 3

Which of these atoms has the greatest atomic radius?

Accepted Answer

barium (Ba)

Answer

Atomic radius generally increases as you move down a group and decreases as you move across a period from left to right on the periodic table. Barium (Ba) is located in Group 2, Period 6, placing it significantly lower and further left than magnesium (Group 2, Period 3), iodine (Group 17, Period 5), and chlorine (Group 17, Period 3). Its position indicates more electron shells and weaker attraction from the nucleus to the outermost electrons, resulting in the largest atomic radius among the choices.

Question 4

Why is cobalt (Co) listed before nickel (Ni) on the periodic table of elements, despite having a higher average atomic mass?

Accepted Answer

Nickel has one more proton.

Answer

The periodic table is primarily ordered by increasing atomic number, which represents the number of protons in an atom's nucleus. Cobalt (Co) has an atomic number of 27, while Nickel (Ni) has an atomic number of 28. Even though cobalt's average atomic mass is slightly higher due to the relative abundance of its isotopes, its lower atomic number dictates its placement before nickel on the periodic table.

Question 5

In theory, as an ideal gas cools in a closed container, the pressure inside gradually decreases until it approaches that of a vacuum. What temperature should this happen at?

Accepted Answer

0 K

Answer

This scenario describes the theoretical concept of absolute zero, which is 0 Kelvin (K). At this temperature, all molecular motion of an ideal gas would cease, meaning the particles would exert no force on the container walls. Consequently, the pressure inside the container would drop to zero, approaching that of a vacuum.

NYSTCE ATAS - NYSTCE Assessment of Teaching Assistant Skills Practice Test

NYSTCE ATAS - NYSTCE Assessment of Teaching Assistant Skills Practice Test

FREE NYSTCE Chemistry Questions and Answers