A--Galena (also known as lead (II) sulfide) is the ore from which elemental lead is extracted. In the first step of the extraction process, galena is heated in oxygen to form lead (II) oxide and sulfur dioxide.
--Write a balanced equation for the reaction. (2 points)
--What mass of galena is converted to lead (II) oxide if 975 kJ of heat is produced? (3 points)
B--Tungsten(VI) oxide reacts with hydrogen gas (H2) to produce tungsten metal and water vapor. The equations below represent the enthalpy change for the formation of the two compounds from their elements.
2 W (s) + 3 O2 (g) ---> 2 WO3 (s) ĂÂH = -1685.4 kJ
2 H2 (g) + O2 (g)---> 2 H2O (g) ĂÂH = -477.84 kJ
--Write a balanced equation for the reaction. (1 point)
--What is the enthalpy change for the overall reaction written in (a)? (4 points)
C---An important step in the synthesis of nitric acid is the reaction of ammonia (NH3) and molecular oxygen to form nitrogen monoxide gas and water vapor.
--Write a balanced equation for this reaction. (2 points)
--Calculate DHo for this reaction, using standard heat of formation values from Appendix G in the Open Stax Chemistry text. (3 points)
D----When an electron in a 2p orbital of a particular atom makes a transition to the 2s orbital, a photon of approximate wavelength 629.1 nm is emitted. What is the energy difference between these 2p and 2s orbitals?
E---Provide a numerical value (whole number) for each of the following questions. Briefly explain your reasoning (1 point each).
How many electrons can be contained in all of the orbitals with n = 4?
Among the orbitals with n = 4 (see part a), which one has the highest energy and how do you know this?
What is the l quantum number for a 4s orbital?
How many electrons can be described by the quantum numbers n = 3, l = 3, ml = 1?
l = 3, how many electrons can be contained in all the possible orbitals of a given principal quantum number?
