(2012?Taizhou) A student used the device as shown in the figure to decompose H2O2 to produce oxygen by using the organs of some plants instead of MnO2 as a catalyst, and the records are shown in the table below.
(1) according to the large particles of potato and small particles of potato comparison experiment can be seen the smaller the particles, the faster the reaction speed, so make the carrot can promote the decomposition of hydrogen peroxide faster, can be used by cutting the carrot into smaller particles;
(2) because the beginning of the reaction when the conical flask of air is pressed into the wide-mouth bottle, the wide-mouth bottle contains a large amount of air, so the fire with a fire in the A wooden stick was stuck into the bottle, but it was found that the stick could not be rekindled.
(3) Let 34 grams of 15% H2O2 solution of solutes completely decomposed, can be produced for the mass of oxygen X then:
2H2O2
2H2O+O2↑
68 32
34 g x 15% x
Based on:
< td style="border-bottom:1px solid black">68
| 32 |
=
Solving for X = 2.4g, the volume of oxygen:
=1.678 liters.
The answers are (1) cut the carrot into smaller particles, (2) oxygen is not pure enough, and (3) 1.678 liters.