Extra Credit 27 (double)
- Page ID
- 83666
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Question 17.3.6
Determine the overall reaction and its standard cell potential at 25 °C for these reactions. Is the reaction spontaneous at standard conditions? Assume the standard reduction for Br2(l) is the same as for Br2(aq).
Steps
1. Write the half reactions (both oxidation and reduction reactions). Don't forget to balance the elements and the electrons.
2. Find the E standard potential for each half reactions.
3. Plug in the values into the equation. E0=cathode - anode to find the total cell potential.
4. Write the overall reaction by combining the two half reactions.
Question 19.1.25
Give the oxidation state of the metal for each of the following oxides of the first transition series. (Hint: Oxides of formula M3O4 are examples of mixed valence compounds in which the metal ion is present in more than one oxidation state. It is possible to write these compound formulas in the equivalent format MO·M2O3, to permit estimation of the metal’s two oxidation states.)
- Sc2O3
- TiO2
- V2O5
- CrO3
- MnO2
- Fe3O4
- Co3O4
- NiO
- Cu2O
Steps
You are asked to find the oxidation state for each metal. First, you have to know that the oxidation state of Oxygen is -2. Using this you can make an equation to find the oxidation state of your uknown metal.
For example.
a) Sc2O3
You know that O has an oxidation state of -2, and the whole compound is neutral (zero charge). there is 3 oxygen atoms and 2 Sc atoms. Set the unknown charge of Sc as x.This allows you to make an equation like below:
2(oxidation state of Sc) + 3(oxidation state of O)=0 (neutral charge)
2x + 3(-2) = 0
Now solve the equation
2x-6=0
2x=6
x=+3
So the oxidation state of Sc is Sc3+ .
Question 12.4.18
Recently, the skeleton of King Richard III was found under a parking lot in England. If tissue samples from the skeleton contain about 93.79% of the carbon-14 expected in living tissue, what year did King Richard III die? The half-life for carbon-14 is 5730 years.
You are asked to find the year that King Richard III died.
Given:
t1/2= 5730 years
N=93.79% =0.9379
N0 (initial) =100%= 1
So you are ultimately trying to find the time that has passed for the carbon to have degraded to that amount.
Steps
1. Find k, using the equation t1/2=ln2/k
2.Plug in the value of k and the given values into the equation ln(N/N0)=-kt to find the time.
These steps are shown in the picture.
Question 21.3.2
Which of the various particles (α particles, β particles, and so on) that may be produced in a nuclear reaction are actually nuclei?
The question is asking which particles contain a nuclei. Nuclei means anything with a nucleus, meaning neutron and proton.
Steps
1. Identify the various particles produced in nuclear reaction.
2. What are they made of?
Question 21.7.4
A scientist is studying a 2.234 g sample of thorium-229 (t1/2 = 7340 y) in a laboratory.
- What is its activity in Bq?
- What is its activity in Ci?
You are asked to find the activity of the sample of Thorium-229.
Given:
Mass: 2.234g
Mr: 229
t1/2=7340yrs
Steps
1. Find the moles of Thorium using the mass and the Mr given.
2. Find the number of atoms that correlates to, to find N. Do this my multiplying moles with Avogadro Number.
3. Find k, using the equation t1/2=ln2/k
4. Convert K=_____/year to K=______/seconds
5. Plug in Values in A=KN
6. Convert Bq to Ci.
Question 20.4.17
The standard cell potential for the oxidation of Pb to Pb2+ with the concomitant reduction of Cu+ to Cu is 0.39 V. You know that E° for the Pb2+/Pb couple is −0.13 V. What is E° for the Cu+/Cu couple?
Steps
1. Write the half reactions (both oxidation and reduction reactions). Don't forget to balance the elements and the electrons.
2. Find the E standard potential for each half reactions.
3. Plug in the values into the equation. E0=cathode - anode to find the unknown value.
4. Write the overall reaction by combining the two half reactions.
0.39V = EoCathode - (-0.13V)
EoCathode = +0.26V
Question 20.9.2
How could you use an electrolytic cell to make quantitative comparisons of the strengths of various oxidants and reductants?
Question 14.1.2
If you were tasked with determining whether to proceed with a particular reaction in an industrial facility, why would studying the chemical kinetics of the reaction be important to you?
Answers on the image attached below