Extra Credit 38

Q17.5.6

Batteries store all the chemicals inside of them. They have Redox reactions to form electricity. When the reaction goes toward completion, the battery dies. However, Fuel cells won't die because as long as there is a flow of reactants and products into the cell, electricity is formed.

Edits in red are done by Audrey.

Q12.3.1

The rate of reaction can be changed by the concentration but the rate constant is always a constant number, and is independent from changes in concentration or changes in the rate.

Edits in red are done by Audrey.

Q12.5.10

\(\displaystyle ln \frac{K_2}{K_1}=\frac{E_a}{R}(\frac{1}{T_1}-\frac{1}{t_2})\) coded by Audrey.

\(\displaystyle ln \frac{1.1*10^{-2}}{4.95}=\frac{E_a}{8.314}(\frac{1}{865}-\frac{1}{703})\) coded by Audrey

Ea=1.91x10⁵J/mol

Q21.4.5

Electron capture occurs when an inner-orbital electron (negatively charged) is captured by the nucleus (positively charged). The electron pulled into the nucleus was most likely found in the 1s orbital. As an electron falls from a higher energy level to replace it, the difference in the energy of the replacement electron in its two energy levels is given off as an X-ray.

Edits in red are done by Audrey.

Q20.2.9

a. \(\displaystyle 8H^{+}+3CuS+8NO_3^{-} \rightarrow 3Cu^{2+}+3SO_4^{2-}+8NO+4H_2O\)

b. \(\displaystyle 5H_2O+6Ag+3HS^{-}+2CrO_4^{2-} \rightarrow 3Ag_2S+2Cr(OH)_3+7OH^{-}\)

c. \(\displaystyle 2H^{+}+Zn+H_2O \rightarrow Zn^{2+}+H_2 +H_2O\)

d. \(\displaystyle 2OH^{-}+O_2+Sb \rightarrow H_2O_2+SbO_2^{-}\)

e. \(\displaystyle 4H^{+}+3UO_2^{2+}+Te \rightarrow 3U^{4+}+TeO_4^{2-}+2H_2O\)

all of these were coded by Audrey

Q20.5.4

We know that in a Redox reaction if it is spontaneous G must be negative. We can use the formula G=-nFE to know that E cell must be negative. We know that n is the electrons transferred in the reaction which is positive. F is a constant positive number. So As a result, E must be positive to make the Redox reaction spontaneous.

Edits in red are done by Audrey.

Q24.5.1

To figure out how many unpaired or paired electrons there are write out the electron configuration and then put them in sublevels one at a time until all sublevels are have one and then make a pair if you need to. This also lets you know if the element/ion is paramagnetic or diamagnetic because paramagnetic have no paired electrons and diamagnetic atoms have paired electrons.

1. The O atom has 2s²2p⁴ as the electron configuration. Therefore, O has 2 unpaired electrons.
2. The Br atom has 4s²3d¹⁰4p⁵ as the electron configuration. Therefore, Br has 1 unpaired electron.
3. The B atom has 2s²2p¹ as the electron configuration, so it has one unpaired electron, it is paramagnetic.
4. The F^- ion has 2s²2p⁶ has the electron configuration, so it has no unpaired electrons which means p sublevel is fully occupied by electrons, it is diamagnetic.
5. The Fe²⁺ ion has 3d⁶ has the electron configuration, so it has 4 unpaired electrons, it is paramagnetic.

Edits in red are done by Audrey.

Q14.7.8

Enzymes have really high efficiency on promoting the rate of the reaction. Catalyst can increase reaction rates by enormous factors (up to 10¹⁷ times the uncatalyzed rate) and tend to be very specific, typically producing only a single product in a quantitative yield. Without the use of catalyst, the industry can't support high needs of a huge population. It's use in meat tenderizers and laundry detergents encourage scientists to explore more applications in other industrial area.

Edits in red are done by Audrey.