Ujian 3 Termodinamika

A 5.000 g sample of methanol, CH₃OH, was combusted in the presence of excess oxygen in a bomb calorimeter conaining 4000 g of water. The temperature of the water increased from 24.000 ^oC to 29.765 ^oC. The heat capacity of the calorimeter was 2657 J/^oC. The specific heat of water is 4.184 J/g^oC. Calculate E for the reaction in kJ/mol.

• -314 kJ/mol

• -789 kJ/mol

• -716 kJ/mol

• -121 kJ/mol

• -69.5 kJ/mol

The entropy will usually increase when

I. a molecule is broken into two or more smaller molecules.

II. a reaction occurs that results in an increase in the number of moles of gas.

III. a solid changes to a liquid.

IV. a liquid changes to a gas.

V. condesation of steam of water

• I

• II

• III

• IV

• V

The standard heat of combustion of ethanol, C₂H₅OH, is 1372 kJ/mol ethanol. How much heat (in kJ) would be liberated by completely burning a 20.0 g sample?

Which statement is incorrect?

• At constant pressure, delta H = delta G + P delta V

• The thermodynamic symbol for entropy is S

• Gibbs free energy is a state function.

• For an endothermic process, delta H is negative.

• If the work done by the system is greater than the heat absorbed by the system, delta E is negative.

How much heat is absorbed in the complete reaction of 3.00 grams of SiO₂ with excess carbon in the reaction below? delta H^o for the reaction is +624.7 kJ.

SiO₂(s) + 3C(s) --> SiC(s) + 2CO(g)

• 366 kJ

• 1.13 x 10⁵ kJ

• 5.06 kJ

• 1.33 x 10⁴ kJ

• 31.2 kJ

Energi tidak dapat di ciptakan dan tidak dapat di musnahkan, namun bentuknya dapat di ubah. Pernyatan tersebut merupakan bunyi hukum…

• A. 1 termodinamika

• B. 2 termodinamika

• C. 3 termodinamika

• D. Kekelan momentum

• E. Energi termodinamika