Answer:
Only one—(i), or (ii), or (iii)—increases the reaction rate.
Explanation:
<em>Which of the following changes always leads to an increase in the rate constant for a reaction?</em>
- <em>Decreasing the temperature. </em>NO. A lower temperature leads to a slower reaction because the molecules have less energy to react.
- <em>Decreasing the activation energy</em>. YES. According to the Arrhenius equation, the lower the activation energy, the higher the rate constant.
- <em>Making the value of ΔE more negative</em>. NO. A more negative ΔE means a reaction is more spontaneous but not faster.
To determine strength of attractive forces between the molecules the size of the molecules, their polarity (dipole moment), and their shape. ... If two molecules have about the same size and similar shape, the dipole-dipole intermolecular attractive force increases with increasing polarity.
If you have a book, read it!! I promise you, it tells you this answer!
the energy gained by proteins and carbohydrates differs from the energy gained by fats.
proteins and carbohydrates both give 4 kcal per gram
fats give 9 kcal per gram
mass of proteins - 2 g
energy given by proteins - 2 g x 4 kcal/g = 8 cal
mass of carbohydrates - 20 g
energy given by carbohydrates - 20 g x 4 kcal/g = 80 cal
mass of fat - 1 g
energy given by fat - 1 g x 9 kcal/g = 9 cal
total energy = 8 + 80 + 9 = 97 kcal
energy = 97 kcal