A solution that has a high amount of solute/concentration in the solvent is concentrated because if there is a lot of solute compared to the solvent, then the ratio of solute to solvent is higher, and thus the concentration is higher too.
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<u>Answer:</u> The correct option is
<u>Explanation:</u>
A catalyst is defined as the chemical species that increases the reaction rate but does not participate in it and is left behind after the completion.
A homogeneous catalyst is one that is present in the same phase as the reactants and products.
A heterogeneous catalyst is one that is present in different phase as that of reactants and products.
For the given chemical reaction:

As all the reactants and products are in gaseous state so, the homogeneous catalyst must also be in the gaseous state only.
Hence, the correct option is 
A chemical change
Explanation:
In this reaction, a chemical change has occurred, here are some indicators of chemical changes from the reaction;
Chemical changes are changes in which new products are formed.
- Formation of bubbles and precipitates: these are new substances that indicates a chemical change. The bubbles and insoluble precipitate are good indicators of chemical change.
- A temperature change that is large; This is also typifies chemical changes. When temperature rises in reaction, a chemical change has occurred.
- The bubbles and precipitates cannot be combined to give the reactants. The reaction is irreversible.
learn more:
Chemical change brainly.com/question/9388643
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the answer is 360 g H2O with a 90.3 yeild percentage