Given the reaction 2hgo → 2hg + o2 , how many moles of elemental mercury will be obtained by the decomposition of 1 mole of hgo?

one mole of HgO will give one mole of Hg.

Explanation:

Given data:

Moles of HgO = 1 mol

Moles of Hg = ?

Solution:

Chemical equation:

2HgO → 2Hg + O₂

Now we will compare the moles of Hg with HgO from balance chemical equation.

                  HgO   :     Hg

                    2       :      2

                     1       :      2/2×1 = 1 mol

So, one mole of HgO will give one mole of Hg.

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.