關於rate of reaction的簡單化學問題

Tieria

2009-07-27 3:21 am

1. In an experiment, a data-logger with pressure sensor was used to study the rate of decomposition of hydrogen peroxide (H2O2) in the presence of manganese (IV) oxide.

(a) The decomposition of hydrogen peroxide gives water and oxygen. After the experiment, it was found that the manganese (IV) oxide used did not undergo any chemical change.
(i) State the function of manganese (IV) oxide.
(ii) Explain why a pressure sensor could be used in this experiment.
(iii) Write a chemical equation for the decomposition of hydrogen peroxide. Hence discuss the changes, if any, in the oxidation numbers of hydrogen and oxygen in the reaction. (5 marks)

回答 (1)

老爺子

2009-07-27 9:34 am

✔ 最佳答案

(i)
Manganese(IV) oxide is used as a catalyst to speed up the reaction.

(ii)
In the experiment, oxygen gas is formed which causes the pressure to increase.

(iii)
2H2O2(aq) → 2H2O(l) + O2(g)
(It is NOT necessary to write the catalyst MnO2 in the equation.)

The oxidation number of H is unchanged.

The oxidation number of O increases from -1 (in H2O2) to 0 (in O2), and decreases from -1 (in H2O2) to -2 (in H2O) at the same time.

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