Heat of Reaction + Entropy

What is the approximate heat of reaction for the formation of 1 mole of H2O(l) in the given equation: 2H2(g) + O2(g)--> 2H2O(l) + 571.6kJ

-285.8kJ

According to Reference Table I, when 2 moles of H2O(g) are formed from its elements,

484kJ of heat is released

Which reaction releases the egreatest amount of energy per 2 moles of product?

4Al(s) + 3O2(g) --> 2Al2O3(s)

According to Reference Table I, which compound is formed from its elements during an exothermic reaction?

CO2(g)

Which 1-mole sample has the least entropy?

Br2(s) at 266K

What is true about the reaction: N2(G) + 3H2(g) --> 2NH3(g) + 91.8kJ

It is exothermic and its heat of reaction is -91.8kJ

Given the reaction: H2O(l) + 286kJ --> H2(g) + 1/2O2(g) Which statement describes the reverse reaction?

It is exothermic and releases 286kJ

According to Table I, which salt releases energy as it dissolves?

LiBr

In terms of energy and entropy, systems in nature tend to undergo changes toward

Lower energy and higher entropy

What is Entropy?

Measure of the disorder of a system

According to Reference Table I, which gas is formed from its elements as a result of an endothermic reaction?

NO2

Which reaction represents the heat of reaction for a chemical reaction in terms of the potential energy of its products and reactants.

PE of Products-PE of Reactants

Why is entropy increasing in this reaction: CaCO3(s) --> CaO(s) + CO2(g)

Particles are becoming more disordered

Above 0 degrees Celsius, ice changes spontaneously to water according to the following equation: H2O(s) + heat --> H2O(l) The changes in H2O(s) involve:

An absorption of heat and a decrease in entropy.

As 1 gram of H2O(l) changes to 1 gram of H2O(s), the entropy of the system

Decreases

Given the reaction: CH4(g) + 2O2(g) --> 2H2O(g) + CO2(g) What is the overall result when CH4 burns according to this reaction?

Energy is absorbed and the heat of reaction is positive.

Which phrase describes the reaction: 4Fe(s) + 3O2(g) --> 2Fe2O3(s) + 1640kJ

Exothermic with a heat of reaction of -1640kJ

Which type of reaction is the haber process N2(g) + 3H2(g) --> 2NH3(g) + heat?

Exothermic, with a decrease in entropy

According to Reference Table I, which statement best describes the formation of HI(g)?

It is endothermic, and heat is absorbed.

A 1 gram sample of a substance has the greatest entropy when it is in the

Gaseous State

As NaCl(s) dissolves according to the equation NaCl(s) --> Na+(aq) + Cl-(aq) the entropy of the system

Increases

Why does the entropy of water decrease when water freezes?

It becomes more organized and less disordered.

Which statement correctly describes an endothermic chemical reaction?

The products have a higher potential energy than the reactants, and the heat of reaction is positive.

According to Reference Table I, heat is liberated during the formation of the compund

Water(g)