Answer:
Manganese dioxide is a catalyst.
Explanation:
The decomposition of hydrogen peroxide into water and oxygen is a slow reaction and MnO₂ is used as a catalyst to speed up the reaction.
The role of MnO₂ (catalyst):
- Chemical reactions occur faster in the presence of a catalyst because the catalyst provides an alternative reaction pathway with a lower activation energy than the non-catalyzed mechanism.
- In catalyzed mechanisms, the catalyst usually reacts to form a temporary intermediate, which then regenerates the original catalyst in a cyclic process.
- A substance which provides a mechanism with a higher activation energy does not decrease the rate because the reaction can still occur by the non-catalyzed route.
- The catalyst does not used up in the reaction.
So, the right choice is:
Manganese dioxide is a catalyst.
The nucleus of an atom of any element is located at the very center. It contains subatomic particles, proton and neutron. That's why it contains the greater mass, because only the electrons orbit the nucleus. So, you would expect the arrow to point somewhere in the center. A picture of nitrogen's nucleus is shown in the attached picture.
The optimal pH is 6.9. The pancreatic amylase is a hydrolase secreted by pancreas and will go into the alimentary canal. The working environment has a pH of 6.9. So the optimal pH for the enzyme needs to be 6.9.
Alfheim
In Norse mythology it means home of Elves and it is known as home to the light elves
