Chemistry Flashcards

Which type of chemical bond results from the electrostatic attraction between oppositely charged ions?

Answer: Ionic bond

Ionic bonds form when one atom transfers electrons to another, creating oppositely charged ions that attract each other.

A student dissolves 5.85 g of NaCl (molar mass 58.5 g/mol) in enough water to make 500 mL of solution. What is the molarity of the solution?

Answer: 0.2 M

Moles of NaCl = 5.85/58.5 = 0.1 mol; Molarity = 0.1 mol / 0.5 L = 0.2 M.

Which of the following best describes an exothermic reaction?

Answer: The reaction releases heat to the surroundings

Exothermic reactions release energy as heat, so the surroundings become warmer.

What is the oxidation state of sulfur in H₂SO₄?

Answer: +6

Each H is +1, each O is −2; solving 2(+1) + S + 4(−2) = 0 gives S = +6.

According to Le Chatelier's principle, what happens to the equilibrium position of N₂ + 3H₂ ⇌ 2NH₃ when pressure is increased?

Answer: Shifts right, producing more NH₃

Increasing pressure favors the side with fewer moles of gas; the right side has 2 moles vs. 4 on the left.

Which subatomic particle determines the identity (atomic number) of an element?

Answer: Proton

The atomic number equals the number of protons, which uniquely identifies each element.

What type of isomers have the same molecular formula and connectivity but differ in the spatial arrangement of atoms?

Answer: Stereoisomers

Stereoisomers share the same connectivity but differ in the three-dimensional arrangement of their atoms in space.