Exam 9: Thermochemistry: Chemical Energy

Imagine a reaction that results in a change in both volume and temperature,as shown in the diagram below.What is the sign of the work being done,and what is the sign of the enthalpy change involved in this reaction?

At 253 K the sign of ΔG for the physical change shown below is ________. H₂O(s)→ H₂O(l)

Calculate the work,w,gained or lost by the system when a gas expands from 15 L to 35 L against a constant external pressure of 1.5 atm.1 L ∙ atm = 101 J

Which is the most exothermic reaction?

In the lab,you mix two solutions (each originally at the same temperature)and the temperature of the resulting solution decreases.Which of the following is true?

The reactants,R + 2 S,are represented by

Use the given average bond dissociation energies,D,to estimate ΔH for the reaction of methane,CH₄(g),with fluorine according to the equation: CH₄(g)+ 2 F₂(g)→ CF₄(g)+ 2 H₂(g)

When 1.820 g of anthracene,C₁₄H₁₀,is combusted in a bomb calorimeter that has a water jacket containing 500.0 g of water,the temperature of the water increases by 34.52°C.Assuming that the specific heat of water is 4.18 J/(g ∙ °C),and that the heat absorption by the calorimeter is negligible,estimate the enthalpy of combustion per mole of anthracene.

In the reaction shown below,________ kJ of heat are released per mole of carbon dioxide(g)that is produced. C₃H₈(g)+ 5 O₂(g)→ 3 CO₂(g)+ 4 H₂O(g)ΔH = -2045 kJ

Find ΔH for C₃H₈ (g)+ 6 H₂O (g)→ 3 CO₂ (g)+ 10 H₂ given C₃H₈ (g)+ 3 H₂O (g)→ 3 CO (g)+ 7 H₂ (g)ΔH = 499 kJ CO (g)+ H₂O (g)→ CO₂ (g)+ H₂ (g)ΔH = -41 kJ

For the reaction I₂(g)→ I₂(s),ΔH° = -62.4 kJ at 25°C.Based on these data,at 25°C

Consider the conversion of white tin to gray tin: Sn(white)→ Sn(gray)ΔH° = -2.09 kJ ΔS° = -7.41 J/K Based on these data,

How much heat is absorbed when 20.00 g of C(s)reacts in the presence of excess SO₂(g)to produce CS₂(l)and CO(g)according to the following chemical equation? 5 C(s)+ 2 SO₂(g)→ CS₂(l)+ 4 CO(g)ΔH° = +239.9 kJ

The values of ΔH°_f for the three states of benzene are approximately -22 kcal/mol,-11 kcal/mol,and Which is the value for solid benzene?

-The reaction represented in the above drawing is likely to be

Which is expected to have the most negative standard enthalpy of formation?

A spontaneous reaction has a ________ value of ΔG and is favored by a ________ value of ΔH and a ________ value of ΔS.

For which should the standard heat of formation ΔH°_f,be zero at 25°C?

When 5.50 g of Ba(s)is added to 100.00 g of water in a container open to the atmosphere,the reaction shown below occurs and the temperature of the resulting solution rises from 22.00°C to 61.16°C.If the specific heat of the solution is 4.18 J/(g ∙ °C),calculate for the reaction,as written. Ba(s)+ 2 H₂O(l)→ Ba(OH)₂(aq)+ H₂(g) = ?

Sodium metal reacts with water to produce hydrogen gas and sodium hydroxide according to the chemical equation shown below.When 0.0500 mol of Na is added to 100.00 g of water,the temperature of the resulting solution rises from 25.00°C to 46.23°C.If the specific heat of the solution is 4.18 J/(g ∙ °C),calculate ΔH for the reaction,as written. 2 Na(s)+ 2 H₂O(l)→ 2 NaOH(aq)+ H₂(g)ΔH = ?