11. Bonding & Molecular Structure

Two positively charged spheres, each with a charge of 2.0 * 10-5 C, a mass of 1.0 kg, and separated by a distance of 1.0 cm, are held in place on a frictionless track. (a) What is the electrostatic potential energy of this system?

(b) What is the change in potential energy if the distance separating the two electrons is increased to 1.0 nm?

(c) Does the potential energy of the two particles increase or decrease when the distance is increased to 1.0 nm?

(a) What is the electrostatic potential energy (in joules) between two electrons that are separated by 460 pm?

(a) The electrostatic force (not energy) of attraction between two oppositely charged objects is given by the equation F = k1Q1Q2>d22where k = 8.99 * 109 N@m2>C2 , Q1 and Q2 are the charges of the two objects in Coulombs, and d is the distance separating the two objects in meters. What is the electrostatic force of attraction (in Newtons) between an electron and a proton that are separated by 0.23 nm?

A sodium ion, Na+, with a charge of 1.6 * 10-19 C and a chloride ion, Cl - , with charge of -1.6 * 10-19 C, are separated by a distance of 0.50 nm. How much work would be required to increase the separation of the two ions to an infinite distance?

A magnesium ion, Mg2+, with a charge of 3.2 * 10-19 C and an oxide ion, O2-, with a charge of -3.2 * 10-19 C, are separated by a distance of 0.35 nm. How much work would be required to increase the separation of the two ions to an infinite distance?

Consider a system consisting of two oppositely charged spheres hanging by strings and separated by a distance r1, as shown in the accompanying illustration. Suppose they are separated to a larger distance r2, by moving them apart. (a) What change, if any, has occurred in the potential energy of the system?

The following diagram shows the potential energy of two atoms as a function of internuclear distance. Match the descriptions with the indicated letter on the plot. (a) Repulsive forces are high between the two atoms. (b) The two atoms neither exert attractive nor repulsive forces on one another. (c) The attractive forces between atoms are maximized, resulting in the lowest energy state. (d) Attractive forces between atoms are present but are not at maximum strength.

Two electrostatic potential maps are shown, one of methyl-lithium (CH3Li) and the other of chloromethane (CH3Cl). Based on their polarity patterns, which do you think is which? (a)

(b)

Electrostatic potential maps of acetaldehyde (C2H4), ethane (C2H6), ethanol (C2H6O), and fluorethane (C2H5F) are shown. Which do you think is which? (a)

(b)

(c)

(d)

According to Coulomb's law, which pair of charged particles has the lowest potential energy? a. a particle with a 1- charge separated by 150 pm from a particle with a 2+ charge b. a particle with a 1- charge separated by 150 pm from a particle with a 1+ charge c. a particle with a 1- charge separated by 100 pm from a particle with a 3+ charge

According to Coulomb's law, rank the interactions between charged particles from lowest potential energy to highest potential energy. a. a 1+ charge and a 1- charge separated by 100 pm b. a 2+ charge and a 1- charge separated by 100 pm c. a 1+ charge and a 1+ charge separated by 100 pm d. a 1+ charge and a 1- charge separated by 200 pm

List the following gas-phase ion pairs in order of the quantity of energy released when they form from separated gas-phase ions. List the pair that releases the least energy first. Na+ F - , Mg2 + F - , Na+O2 - , Mg2 +O2 - , Al3 +O2 - .

Use Coulomb's law to calculate the ionization energy in kJ>mol of an atom composed of a proton and an electron separated by 100.00 pm. What wavelength of light has sufficient energy to ionize the atom?

The first ionization energy of sodium is 496 kJ>mol. Use Coulomb's law to estimate the average distance between the sodium nucleus and the 3s electron. How does this distance compare to the atomic radius of sodium? Explain the difference.