Given the following reactions, estimate the overall enthalpy change for the dissolution of solid sodium hydroxide in water: NaOH(s) → Na+(aq) + OH-(aq).  Na(s) + ½H2(g) + ½O2(g) → NaOH(s)      ∆H° = −427 kJ/mol  Na(s) + H2O(l) → Na+(aq) + OH-(aq) + ½H2(g)      ∆H° = −184 kJ/mol  2 H2(g) + O2(g) → 2 H2O(l)      ∆H° = −572 kJ/mol 

Using ∆H°f(glucose) = −1274.4 kJ/mol, ∆H°f(H2O, l) = −187.8 kJ/mol, and ∆H°f(CO2, g) = −412.9 kJ/mol, calculate ∆H°rxn for the combustion of glucose [C6H12O6(s) + 6 O2(g) → 6 CO2(g) + 6 H2O(l)]. 

Which of these compounds results in the strongest electrolyte solution when dissolved in water?

When 80.0 J of energy is absorbed by 0.50 mol of water, how much does the temperature rise? The specific heat of water is 4.184 J/g·K.

An automobile air conditioner uses liquid R-134a (normal boiling point −26 °C). Inside the cabin, the pressurized liquid is allowed to expand and evaporate into a gas. At the molecular level, why does this evaporation cool the cabin air? 

All of the following ionic compounds of the Ni(II) cation are insoluble EXCEPT (i.e., which anion forms a soluble compound with Ni(II)?)

In the same room and open to the atmosphere, two identical flasks of distilled water are heated. One is boiling vigorously; the other is boiling gently. Which statement is true?

Using the balanced equation H2(g) + I2(g) ⇌ 2 HI(g), the correct equilibrium expression K is: 

The individual C=O bonds in CO2 are polar. Considering the shape of the molecule, the overall CO2 molecule is ________.

Two compounds are structural (constitutional) isomers when they have ________.