PICTURES & GRAPHS
A. The Atom
1. Calculate the average atomic mass using the spectrum below.
2. Answer the questions regarding the energy level diagram shown.
a) The emission lines for the series above are in the IR, Vis and UV regions. Match the series with the region and justify your choice (FYI – AP you do not need to memorize the names of the series. IB will need to know then for next year).
b) Would the wavelength of light be longer or shorter for lithium for an n=2 to n=1 transition than it would be for hydrogen? Justify your answer.
1. Answer the following questions regarding potential energy curves.
a) One side of the curve represents increases in attractive forces and the other increases in repulsive forces. Label the two sides.
b) Label the point on the curve that represents the average bond distance between two atoms. Why is this distance called the “average” bond distance? What part of the electromagnetic spectrum would be used to study this?
c) Draw and label a curve that shows what would change if the bond is a triple bond as opposed to a single bond.
2. Answer the following questions regarding the potential energy curves for Cl2, N2, and I2, as shown below.
a) Label the axis. Potential energy is in KJ/mol and bond length is in picometers.
b) Label the curves for Cl2, N2, and I2. Justify your choice.
c) Which requires energy: bond formation or bond breaking? Justify your answer.
d) What is the bond energy in joules for one molecule of nitrogen?
3. The graph below shows the effect of changing temperature on the vapor pressure for two liquids, ethane and water. Ethane Ethanol
a) Explain why vapor pressure increases with increasing temperature.
b) Identify the intermolecular forces involved for each substance.
c) Indicate which curve is likely water and which curve is ethane. Justify your