Suppose the volume of a container is decreased, but the same number of gas molecules is present at the same temperature. what will happen to the molecules? the molecules will increase in number. the molecules will decrease in number. there will be more molecules per unit volume. there will be less molecules per unit volume.

Option (C) is the correct answer.

Explanation:

When the volume of a container is decreased and same number of gas molecules are present inside the container at the same temperature then it means that more number of gas molecules are spread per unit volume.

As earlier when the volume of container was more then the molecules were widely spread inside the container but on decreasing the volume of container, molecules come closer to each other and hence there will be increase in molecules per unit volume.  

2h2o2--> 2h2o + o2

this reaction is of the spontaneous decomposition of hydrogen peroxide down into water and oxygen.

add 2 molecules of hydrogen peroxide and 2 molecules of water. since oxygen is naturally diatomic, the total number of atoms of each element is now the same on both sides of the equation so it is balanced.

this may not be entirely correct but let me know.

the answer is barium and copper bromide