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.
Answer:
<h2>Because energy is conserved, the kinetic energy of a block at the bottom of a frictionless ramp is equal to the gravitational potential energy of the block at the top of the ramp. ... Therefore, the block's final velocity depends on the height of the ramp but not the steepness.</h2>
This should help :)
Example 1: A 36.0 g sample of water is initially at 10.0 °C.
How much energy is required to turn it into steam at 200.0 °C? (This
example starts with a temperature change, then a phase change followed
by another temperature change.)
Solution:
<span>q = (36.0 g) (90.0 °C) (4.184 J g¯1 °C¯1) = 13,556 J = 13.556 kJ
q = (40.7 kJ/mol) (36.0 g / 18.0 g/mol) = 81.4 kJ
q = (36.0 g) (100.0 °C) (2.02 J g¯1 °C¯1) = 7272 J = 7.272 kJ
q = 102 kJ (rounded to the appropriate number of significant figures)
</span>
Answer: A)
Explanation:
the deposition environment has changed from wind-dominated in the past to stream-dominated today.
I think its mass of volume
