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)

Which of the following statements is/are CORRECT?   1. If a reaction occurs at constant pressure, q = ΔH.   2. The change in energy for a system is defined as the sum of the energies transferred as heat and work (i.e., ΔU = q + w).   3. If a reaction occurs at constant volume, q = w

In the Lewis formula for sulfur dioxide, SO2, the number of lone pairs of electrons around the sulfur atom is

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?

When 66.0 g of an unknown metal at 28.5 °C is placed in 83.0 g H2O at 78.5 °C, the water temperature decreases to 75.9 °C. What is the specific heat capacity of the metal? The specific heat capacity of water is 4.184 J/g⋅K.

Which of the following colors of visible light has the longest wavelength?

If 46.1 g of copper at 11.6 °C is placed in 85.0 g of water at 72.4 °C, what is the final temperature of the mixture? The specific heat capacities of copper and water are 0.385 J/g ⋅ K and 4.184 J/g ⋅ K, respectively.

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.

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)

Which of the following molecules or ions are isoelectronic: SO3, NF3, NO3–, CO32–?