Last minute guide to passing HESI A2 Chemistry questions and answers

What happens to the pH of a solution when a small amount of strong acid is added to a buffer system ️️ The pH changes only slightly because the buffer resists drastic changes Why does increasing temperature generally increase reaction rate ️️ Particles gain kinetic energy and collide more frequently and with greater energy What type of bond forms when electrons are shared equally between two atoms ️️ A nonpolar covalent bond What is the main difference between an isotope and an ion ️️ Isotopes differ in neutron number while ions differ in electron number How does a catalyst affect the activation energy of a reaction ️️ It lowers the activation energy required What is the concentration of hydrogen ions in a neutral solution at 25°C ️️ 1 × 10−7 M What is the purpose of a titration experiment ️️ To determine the concentration of an unknown solution What type of intermolecular force is strongest among molecules ️️ Hydrogen bonding What is the result when an acid reacts with a base ️️ Formation of salt and water What does the term “limiting reactant” mean ️️ The reactant that is completely consumed first and limits product formation Why are noble gases chemically unreactive ️️ They have full valence electron shells What happens to gas volume when pressure increases at constant temperature ️️ The volume decreases What is the molar mass of a substance used for ️️ To convert between grams and moles 2 What type of reaction involves the combination of two substances into one product ️️ Synthesis reaction Why do ionic compounds conduct electricity in solution ️️ They dissociate into free-moving ions What is the oxidation number of oxygen in most compounds ️️ −2 What is the function of an indicator in acid-base reactions ️️ To show a visible color change at a certain pH What happens to equilibrium when more product is added ️️ The reaction shifts toward the reactants What type of bond forms between a metal and a nonmetal ️️ Ionic bond What is the main component of natural gas ️️ Methane What is the relationship between frequency and wavelength ️️ They are inversely proportional What is the charge of a proton ️️ Positive What is the process of a solid turning directly into gas called ️️ Sublimation What determines the identity of an element ️️ The number of protons What is Avogadro’s number ️️ 6.022 × 1023 particles per mole What happens when a solution becomes supersaturated ️️ It contains more dissolved solute than normally possible What is the unit of pressure commonly used in gas laws ️️ Atmospheres (atm) What is the difference between endothermic and exothermic reactions ️️ Endothermic absorbs heat, exothermic releases heat 3 What type of mixture has uniform composition throughout ️️ Homogeneous mixture What is the main factor that affects solubility of gases in liquids ️️ Pressure What is the electron configuration of an atom used to determine ️️ Chemical reactivity and bonding What is the pH range of acidic solutions ️️ Less than 7 What happens to reaction rate when concentration increases ️️ Reaction rate increases What is the main component of an acid ️️ Hydrogen ions (H+) What type of radiation has the highest energy ️️ Gamma rays What is the function of a salt bridge in an electrochemical cell ️️ It maintains electrical neutrality What is the difference between accuracy and precision ️️ Accuracy is closeness to true value, precision is consistency What is a mole ratio used for in stoichiometry ️️ To convert between amounts of substances What is the state of matter with fixed volume but no fixed shape ️️ Liquid What is the boiling point of water at standard pressure ️️ 100°C What type of bond involves unequal sharing of electrons ️️ Polar covalent bond What happens when electrons move to a higher energy level ️️ They absorb energy What is the strongest type of chemical bond ️️ Covalent bond 4 What is the role of enzymes in chemical reactions ️️ They act as biological catalysts What is the formula for calculating density ️️ Mass divided by volume What is the term for a solution that can dissolve more solute