Chemistry

Cards (24)

• 1
  Front

  What are the three subatomic particles of an atom and their charges?

  Back

  Protons (positive charge), neutrons (no charge), and electrons (negative charge).

• 2
  Front

  What defines the atomic number of an element?

  Back

  The atomic number is the number of protons in the nucleus of an atom.

• 3
  Front

  What is the difference between atomic mass and mass number?

  Back

  Mass number is the total count of protons and neutrons in a specific nucleus. Atomic mass is the weighted average mass of all naturally occurring isotopes of an element.

• 4
  Front

  What are isotopes?

  Back

  Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons.

• 5
  Front

  How are elements arranged in the modern periodic table?

  Back

  Elements are arranged in order of increasing atomic number, organized into periods (rows) and groups (columns) based on similar chemical properties.

• 6
  Front

  What is the general trend in electronegativity across a period and down a group?

  Back

  Electronegativity increases across a period (left to right) and decreases down a group.

• 7
  Front

  What is the difference between an ionic bond and a covalent bond?

  Back

  An ionic bond involves the transfer of electrons between atoms, creating oppositely charged ions. A covalent bond involves the sharing of electrons between atoms.

• 8
  Front

  What type of bonding occurs in metals?

  Back

  Metallic bonding, where positively charged metal ions are surrounded by a 'sea' of delocalized electrons.

• 9
  Front

  What is a polar covalent bond?

  Back

  A covalent bond in which electrons are shared unequally due to a difference in electronegativity between the two bonded atoms, creating partial positive and negative charges.

• 10
  Front

  What does a mole represent in chemistry?

  Back

  A mole represents 6.022 × 10²³ entities (Avogadro's number), whether atoms, molecules, ions, or other particles.

• 11
  Front

  How is molar mass used to convert between grams and moles?

  Back

  Moles = mass (g) ÷ molar mass (g/mol). Molar mass equals the mass in grams of one mole of a substance, numerically equal to its atomic or molecular weight in amu.

• 12
  Front

  What is the difference between a limiting reagent and an excess reagent?

  Back

  The limiting reagent is completely consumed in a reaction and determines the maximum amount of product formed. The excess reagent is present in greater quantity than needed and remains after the reaction.

• 13
  Front

  State Boyle's Law.

  Back

  At constant temperature, the pressure and volume of a gas are inversely proportional: P₁V₁ = P₂V₂.

• 14
  Front

  What does Charles's Law state?

  Back

  At constant pressure, the volume of a gas is directly proportional to its absolute temperature (in Kelvin): V₁/T₁ = V₂/T₂.

• 15
  Front

  What is the Ideal Gas Law equation?

  Back

  PV = nRT, where P is pressure, V is volume, n is moles of gas, R is the ideal gas constant (0.0821 L·atm/mol·K), and T is temperature in Kelvin.

• 16
  Front

  What is the difference between exothermic and endothermic reactions in terms of enthalpy?

  Back

  Exothermic reactions release heat to the surroundings, so ΔH is negative. Endothermic reactions absorb heat from the surroundings, so ΔH is positive.

• 17
  Front

  What does Hess's Law state?

  Back

  The total enthalpy change of a reaction is the same regardless of the pathway taken, so ΔH values of individual steps can be added to find the overall ΔH.

• 18
  Front

  According to the Brønsted-Lowry definition, what are an acid and a base?

  Back

  A Brønsted-Lowry acid is a proton (H⁺) donor, and a Brønsted-Lowry base is a proton acceptor.

• 19
  Front

  What is the relationship between pH and hydrogen ion concentration?

  Back

  pH = −log[H⁺]. A lower pH indicates a higher [H⁺] and a more acidic solution; a higher pH indicates a more basic solution.

• 20
  Front

  What is the ion product of water (Kw) at 25°C?

  Back

  Kw = [H⁺][OH⁻] = 1.0 × 10⁻¹⁴ at 25°C, meaning pure water has [H⁺] = [OH⁻] = 1.0 × 10⁻⁷ M.

• 21
  Front

  What does Le Chatelier's Principle state?

  Back

  If a system at equilibrium is disturbed by a change in concentration, pressure, or temperature, the equilibrium will shift in the direction that partially counteracts the disturbance.

• 22
  Front

  What does a large equilibrium constant (K >> 1) indicate about a reaction?

  Back

  A large K indicates that at equilibrium the products are favored, meaning the reaction proceeds mostly to the right.

• 23
  Front

  What are oxidation and reduction in terms of electron transfer?

  Back

  Oxidation is the loss of electrons (increase in oxidation number). Reduction is the gain of electrons (decrease in oxidation number). They always occur together in redox reactions.

• 24
  Front

  What is the mnemonic OIL RIG used for in redox chemistry?

  Back

  OIL RIG stands for Oxidation Is Loss (of electrons), Reduction Is Gain (of electrons), helping to distinguish the two half-reactions in a redox process.