Answer:
a property whose value does not depend on the path taken to reach that specific value.
Explanation:
The correct answers are :
Changing the volume of the system.
Changing the temperature of the system.
Equilibrium will remain unaffected if the concentration of products and reactants are kept the same, and the temperature of the system is kept constant.
As the system is closed, we cannot add or remove products or reactants.
Change in temperature will shift the chemical equilibrium towards the reactant or product depending on whether the reaction is exothermic or endothermic.
Also change in volume will shift the chemical equilibrium of a chemical reaction if the reactants or products or both are gases.
Answer : The limiting reagent is 
Solution : Given,
Moles of methane = 2.8 moles
Moles of
= 5 moles
Now we have to calculate the limiting and excess reagent.
The balanced chemical reaction is,

From the balanced reaction we conclude that
As, 2 mole of
react with 1 mole of 
So, 5 moles of
react with
moles of 
From this we conclude that,
is an excess reagent because the given moles are greater than the required moles and
is a limiting reagent and it limits the formation of product.
Hence, the limiting reagent is 
Protons identity the element because the number of protons gives us the atomic number of each element