How much heat is liberated at constant pressure if 0.515 g of calcium carbonate reacts with 32.7 mL of 0.498 M hydrochloric acid? CaCO3(s) + 2HCl(aq)  →  CaCl2(aq) + H2O(l) + CO2(g); ΔrH° = –15.2 kJ/mol-rxn

Hydrazine, N2H4, is a liquid used as a rocket fuel. It reacts with oxygen to yield nitrogen gas and water. N2H4() + O2(g) → N2(g) + 2 H2O() The reaction of 6.50 g N2H4 evolves 126.2 kJ of heat. Calculate the enthalpy change per mole of hydrazine combusted.

Which of the following thermodynamic quantities are state functions: heat (q), work (w), enthalpy change (ΔH), and/or internal energy change (ΔU)?

What is the energy per mole of photons of light with a wavelength of 690.8 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)

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?