Question

energy in reactions

1. the graphs below show the amount of energy present during two chemical reactions. one of the reactions is an energy - absorbing reaction, the other is an energy - releasing reaction. label the type of reaction for each, label the energy level for the reactants and products, then draw an arrow on each to show the energy of activation.

graphs of energy vs course of reaction

type of reaction: ____________
type of reaction: ____________

1. what is released or absorbed whenever chemical bonds form or are broken?
2. what is the energy of activation?
3. of the two reactions shown, which one is more likely to start spontaneously and why?

enzymes

1. how does the addition of a catalyst affect the energy of activation of a chemical reaction?
2. what type of catalysts affect biochemical reactions?
3. what makes proteins the ideal types of compounds to act as enzymes?

Explanation:

Step1: Identify reaction types from graphs

In the first graph, products have higher energy than reactants, so it is an endothermic (energy - absorbing) reaction. In the second graph, products have lower energy than reactants, so it is an exothermic (energy - releasing) reaction.

Step2: Answer question 4

Energy is released or absorbed whenever chemical bonds form or are broken. Exothermic reactions release energy when bonds form in products, and endothermic reactions absorb energy to break bonds in reactants.

Step3: Answer question 5

The energy of activation is the minimum amount of energy that reactant molecules must have in order to undergo a chemical reaction. It is the energy difference between the reactants and the transition - state.

Step4: Answer question 6

The exothermic reaction (second graph) is more likely to start spontaneously. This is because it has a net release of energy, and the products are more stable than the reactants. Spontaneous reactions tend to proceed in the direction of lower energy.

Step5: Answer question 7

The addition of a catalyst lowers the energy of activation of a chemical reaction. A catalyst provides an alternative reaction pathway with a lower activation energy, allowing the reaction to occur more easily and at a faster rate.

Step6: Answer question 8

Enzymes are the type of catalysts that affect biochemical reactions. Enzymes are biological macromolecules (usually proteins) that speed up chemical reactions in living organisms.

Step7: Answer question 9

Proteins are ideal as enzymes because they have complex three - dimensional structures. These structures allow them to have specific active sites where substrates can bind, and they can also undergo conformational changes to facilitate the reaction.

Answer:

1. First graph: Endothermic reaction; Second graph: Exothermic reaction
2. Energy
3. The minimum amount of energy that reactant molecules must have to undergo a chemical reaction
4. The exothermic reaction (second graph) because it has a net release of energy and products are more stable
5. It lowers the energy of activation
6. Enzymes
7. They have complex three - dimensional structures with specific active sites and can undergo conformational changes