NYSTCE ATAS NYSTCE Chemistry 4 — Questions and Answers
Question 1: Which of the following best describes an atom that has gained one or more electrons?
- A cation with a positive charge
- An anion with a negative charge (Correct answer)
- An isotope
- A neutral atom
Correct answer: An anion with a negative charge
An atom that gains electrons acquires extra negative charge and is called an anion.
Question 2: The Law of Conservation of Mass states that in a chemical reaction:
- Mass is created as new products form
- The total mass of reactants equals the total mass of products (Correct answer)
- Some mass is always lost as energy
- Products always have greater mass than reactants
Correct answer: The total mass of reactants equals the total mass of products
Mass cannot be created or destroyed in a chemical reaction; the total mass of reactants always equals the total mass of products.
Question 3: Which type of mixture can be separated by filtration?
- A solution of salt in water
- A suspension of sand in water (Correct answer)
- A homogeneous mixture
- An alloy
Correct answer: A suspension of sand in water
Suspensions contain large undissolved particles that can be physically trapped by a filter, unlike dissolved solutes in a solution.
Question 4: When balancing a chemical equation, which of the following may be changed to achieve balance?
- The subscripts in chemical formulas
- The coefficients in front of formulas (Correct answer)
- The identity of the reactants
- The products formed
Correct answer: The coefficients in front of formulas
Only coefficients (numbers in front of formulas) are changed to balance equations; subscripts cannot be altered because they define the compound.
Question 5: Which particle has negligible mass and orbits the nucleus of an atom?
- Proton
- Neutron
- Electron (Correct answer)
- Quark
Correct answer: Electron
Electrons have a very small mass (about 1/1836 of a proton) and occupy the electron cloud (orbitals) surrounding the nucleus.
Question 6: Charles's Law describes the relationship between the temperature and volume of a gas at constant pressure. If a gas is heated, its volume will:
- Decrease proportionally
- Remain unchanged
- Increase proportionally (Correct answer)
- First increase then decrease
Correct answer: Increase proportionally
Charles's Law states that volume and temperature (in Kelvin) are directly proportional at constant pressure, so heating causes the gas to expand.
Question 7: A teaching assistant is helping a student who does not understand why water is called a polar molecule. The BEST explanation is that water is polar because:
- It contains hydrogen atoms
- Its electrons are unevenly distributed due to the bent molecular shape (Correct answer)
- It is a liquid at room temperature
- It can dissolve many substances
Correct answer: Its electrons are unevenly distributed due to the bent molecular shape
Water's bent shape and the electronegativity difference between oxygen and hydrogen cause an uneven distribution of charge, making it polar.
NYSTCE ATAS NYSTCE Chemistry 4
Which of the following best describes an atom that has gained one or more electrons?