The thermochemical equation for the combustion of methanol is given below.   CH3OH() + 3/2 O2(g) → CO2(g) + 2 H 2O(g) ΔrH° = –638.7 kJ/mol-rxn What is the enthalpy change for the combustion of 8.59 g of CH3OH?

If the de Broglie wavelength of an electron is 44 nm, what is its velocity? (The mass of an electron is 9.11 × 10–31 kg.)

A 18.6-g piece of gold (s = 0.129 J/(g·°C)), initially at 285.4°C, is added to 147.2 g of a liquid, initially at 27.9°C, in an insulated container. The final temperature of the metal–liquid mixture at equilibrium is 28.9°C. What is the identity of the liquid? Neglect the heat capacity of the container.

​What is the energy of a photon of electromagnetic radiation with a wavelength of 165.2 nm? 

What is the wavelength of light emitted when an electron in a hydrogen atom undergoes a transition from energy level n = 6 to level n = 1? (c  = 3.00  × 108 m/s, h =  6.63 × 10–34 J·s, RH  =  2.179 × 10–18 J)

A red laser pointer emits light at a wavelength of 488 nm. If the laser emits 7.5 × 10–4 J of energy per second in the form of visible radiation, how many photons per second are emitted from the laser?

What is the minimum mass of ice at 0.0 °C that must be added to 1.00 kg of water to cool the water from 28.0 °C to 12.0 °C? (Heat of fusion = 333 J/g; specific heat capacities: ice = 2.06 J/g⋅K, liquid water = 4.184 J/g⋅K)

At constant pressure and 25°C, what is ΔrH° for the following reaction 2C2H6(g) + 7O2(g) → 4CO2(g) + H2O(l) if the complete consumption of 22.7 g of C2H6 liberates –1178 kJ of heat energy?

What quantity, in moles, of hydrogen is consumed when 179.6 kJ of energy is evolved from the combustion of a mixture of H2(g) and O2(g)? H2(g) + O2(g)  →  H2O(l); ΔrH° = –285.8 kJ/mol-rxn

Calculate ΔU of a gas for a process in which the gas absorbs 45 J of heat and does 11 J of work by expanding.