Calculate the energy associated with a photon that has a wavelength of 2 cm (10⁻² m). Without rounding your answer, what is the first integer digit of your numerical answer expressed in standard SI units of joules?

57. The molecular mass of the compound in Question 56 is 194.19 g/mol. What is its molecular formula?

45. The rocket booster reaction is best classified as an oxidation–reduction reaction. Three elements undergo a change in oxidation number. Which list correctly identifies those three elements and what happens to each?

Under which of these conditions — (1) Constant Temperature, (2) Constant Pressure, (3) Constant Volume — is the enthalpy change (∆H) of a process equal to the amount of heat energy transferred into or out of the surroundings? 

Nitrous oxide (N2O) is described as very soluble in (nonpolar) cream but only slightly soluble in water. Based on this “like dissolves like” evidence, N2O is best described as:

At 971 K the equilibrium constant for H2(g) + I2(g) ⇌ 2 HI(g) is K = 1.84 × 10-2. Which statement is correct? 

Which choice correctly expresses (i) how ∆G is related to ∆S(universe) and (ii) how ∆S(surroundings) is related to ∆H (at constant T and P)?

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 . 

For the combustion of glucose (C6H12O6), which choice gives the correct balanced equation AND the correct sign of ∆S (with reason)? 

If 1.86 g of HF is dissolved in water to make 200 mL of solution, what is the molarity of the solution? (HF molar mass ≈ 20.01 g/mol.)