38) in chemical reactions, electricity, a spark, and sunlight are all ways in which ____________ may be…

38) in chemical reactions, electricity, a spark, and sunlight are all ways in which ____________ may be provided.\n(a) reactants\n(b) products\n(c) activation energy\n(d) catalysts\n\n40) which of the following will slow down the rate of a chemical reaction?\n(a) increasing the surface area of the reactants\n(b) increasing the concentration of reactants\n(c) addition of a catalyst\n(d) decreasing the temperature\n(e) increasing the pressure\n\n41) for an effective collision to take place, there must be (choose two answers)\n(a) a sufficiently hard collision\n(b) a catalyst present\n(c) a correctly oriented collision\n(d) high pressure\n(e) no products present

38) in chemical reactions, electricity, a spark, and sunlight are all ways in which ____________ may be provided.\n(a) reactants\n(b) products\n(c) activation energy\n(d) catalysts\n\n40) which of the following will slow down the rate of a chemical reaction?\n(a) increasing the surface area of the reactants\n(b) increasing the concentration of reactants\n(c) addition of a catalyst\n(d) decreasing the temperature\n(e) increasing the pressure\n\n41) for an effective collision to take place, there must be (choose two answers)\n(a) a sufficiently hard collision\n(b) a catalyst present\n(c) a correctly oriented collision\n(d) high pressure\n(e) no products present

Answer

Brief Explanations:

  1. Activation energy can be provided in forms like electricity, a spark, and sunlight in chemical reactions. Reactants are the starting - materials, products are the end - results, and catalysts speed up reactions without being consumed.
  2. Increasing surface area, concentration, adding a catalyst, and increasing pressure generally speed up reactions. Decreasing temperature slows down the motion of reactant particles, thus slowing down the reaction rate.
  3. For an effective collision (which leads to a reaction), there must be sufficient energy (sufficiently hard collision) and correct orientation of the colliding particles. A catalyst can increase the frequency of effective collisions but is not a requirement for an effective collision to occur initially, high pressure is not a necessary condition for every effective collision, and the absence of products is not a condition for an effective collision.

Answer:

  1. C. activation energy
  2. D. Decreasing the temperature
  3. A. A sufficiently hard collision, C. A correctly oriented collision