Answer:- D. 1.8 moles of Fe and
.
Solution:- The balanced equation is:

let's first figure out the limiting reactant using the given moles and mol ratio:

= 5.4 mol CO
From calculations, 5.4 moles of CO are required to react completely with 1.8 moles of Iron(III)oxide but only 2.7 moles of CO are available. It means CO is limiting reactant.
Products moles depends on limiting reactant. Let's calculate the moles of each reactant formed for given 2.7 moles of CO.

= 1.8 mol Fe

= 
So, the correct choice is D. 1.8 moles of Fe and
are formed.
Answer:
Here, we are required to determine the total energy of the reaction and determine if the reaction is an endothermic or exothermic reaction.
The correct answer is option C.
First, we need to determine the energy of the reaction.
The energy of the reaction is the change in enthalpy between the product and reactants.
Change of Enthalpy,
Hreaction = Hproduct - Hreactant.
Therefore, for the reaction above, the change in enthalpy is:
Hreaction = 590kJ/mol - 581kJ/mol.
Hreaction = 9kJ/mol.
Hence, since the reaction has an enthalpy change of 9kJ/mol, the reaction is endothermic (i.e energy is absorbed).
Explanation:
The correct answer is:
b: Heluim
Explanation:
The caffeine contains:
carbon , nitrogen , oxygen ,
hydrogen.
Caffeine is a primary nervous system energizer of the methylxanthine class. It is the world's most universally consumed psychoactive drug. Unlike many other psychoactive elements, it is fair and unlimited in nearly all parts of the world. Caffeine can be arranged as an alkaloid, a term used for substances originated as end results of nitrogen metabolism in some plants.
1. A thermodynamic quantity that is the difference between the internal energy of a system and the product of itsabsolute temperature and entropy; the capacity of a system to do work, as in an exothermic chemical reaction.<span>2. </span>A thermodynamic quantity that is the difference between the enthalpy and the product of the absolute temperatureand entropy of a system. Also called <span>Gibbs free energy</span>.