Chemistry Flashcards
7 cards from real Regents practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Chemistry flashcards as text
What is the oxidation state of sulfur in H₂SO₄?
Answer: +6
In H₂SO₄, hydrogen is +1 (×2) and oxygen is -2 (×4), so sulfur must be +6 to balance the overall neutral charge.
Which of the following best describes an exothermic reaction?
Answer: Energy is released to the surroundings
Exothermic reactions release energy to the surroundings, causing the environment to feel warmer.
Which statement correctly describes isotopes of the same element?
Answer: Same number of protons, different neutrons
Isotopes have the same number of protons (same element) but different numbers of neutrons, giving them different mass numbers.
In a redox reaction, the substance that gains electrons is called the:
Answer: Oxidizing agent
The oxidizing agent gains electrons (is reduced) while causing the other substance to be oxidized.
What is the molar mass of Ca(OH)₂?
Answer: 74 g/mol
Ca = 40, O = 16×2 = 32, H = 1×2 = 2; total = 40 + 32 + 2 = 74 g/mol.
Which intermolecular force is responsible for the unusually high boiling point of water?
Answer: Hydrogen bonding
Hydrogen bonding between water molecules requires significantly more energy to overcome, resulting in water's abnormally high boiling point of 100°C.
What happens to the rate of a chemical reaction when a catalyst is added?
Answer: Rate increases
A catalyst increases the reaction rate by providing an alternative pathway with lower activation energy, without being consumed.