# 13.1 Occurrence, preparation, and properties of transition metals  (Page 12/27)

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Iron(II) can be oxidized to iron(III) by dichromate ion, which is reduced to chromium(III) in acid solution. A 2.5000-g sample of iron ore is dissolved and the iron converted into iron(II). Exactly 19.17 mL of 0.0100 M Na 2 Cr 2 O 7 is required in the titration. What percentage of the ore sample was iron?

2.57%

How many cubic feet of air at a pressure of 760 torr and 0 °C is required per ton of Fe 2 O 3 to convert that Fe 2 O 3 into iron in a blast furnace? For this exercise, assume air is 19% oxygen by volume.

Find the potentials of the following electrochemical cell:

Cd | Cd 2+ , M = 0.10 ‖ Ni 2+ , M = 0.50 | Ni

0.167 V

A 2.5624-g sample of a pure solid alkali metal chloride is dissolved in water and treated with excess silver nitrate. The resulting precipitate, filtered and dried, weighs 3.03707 g. What was the percent by mass of chloride ion in the original compound? What is the identity of the salt?

The standard reduction potential for the reaction ${\left[\text{Co}{\left({\text{H}}_{2}\text{O}\right)}_{6}\right]}^{3+}\left(aq\right)+{\text{e}}^{-}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\left[{\text{Co}\left(\text{H}}_{2}\text{O}{\right)}_{6}\right]}^{2+}\left(aq\right)$ is about 1.8 V. The reduction potential for the reaction ${\left[\text{Co}{\left({\text{NH}}_{3}\right)}_{6}\right]}^{3+}\left(aq\right)+{\text{e}}^{-}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\left[\text{Co}{\left({\text{NH}}_{3}\right)}_{6}\right]}^{2+}\left(aq\right)$ is +0.1 V. Calculate the cell potentials to show whether the complex ions, [Co(H 2 O) 6 ] 2+ and/or [Co(NH 3 ) 6 ] 2+ , can be oxidized to the corresponding cobalt(III) complex by oxygen.

E ° = −0.6 V, E ° is negative so this reduction is not spontaneous. E ° = +1.1 V

Predict the products of each of the following reactions. (Note: In addition to using the information in this chapter, also use the knowledge you have accumulated at this stage of your study, including information on the prediction of reaction products.)

(a) ${\text{MnCO}}_{3}\left(s\right)+\text{HI}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶$

(b) $\text{CoO}\left(s\right)+{\text{O}}_{2}\left(g\right)\phantom{\rule{0.2em}{0ex}}⟶$

(c) $\text{La}\left(s\right)+{\text{O}}_{2}\left(g\right)\phantom{\rule{0.2em}{0ex}}⟶$

(d) $\text{V}\left(s\right)+{\text{VCl}}_{4}\left(s\right)\phantom{\rule{0.2em}{0ex}}⟶$

(e) $\text{Co}\left(s\right)+{xs\text{F}}_{2}\left(g\right)\phantom{\rule{0.2em}{0ex}}⟶$

(f) ${\text{CrO}}_{3}\left(s\right)+\text{CsOH}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶$

Predict the products of each of the following reactions. (Note: In addition to using the information in this chapter, also use the knowledge you have accumulated at this stage of your study, including information on the prediction of reaction products.)

(a) $\text{Fe}\left(s\right)+{\text{H}}_{2}{\text{SO}}_{4}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶$

(b) ${\text{FeCl}}_{3}\left(aq\right)+\text{NaOH}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶$

(c) $\text{Mn}{\left(\text{OH}\right)}_{2}\left(s\right)+\text{HBr}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶$

(d) $\text{Cr}\left(s\right)+{\text{O}}_{2}\left(g\right)\phantom{\rule{0.2em}{0ex}}⟶$

(e) ${\text{Mn}}_{2}{\text{O}}_{3}\left(s\right)+\text{HCl}\left(aq\right)⟶$

(f) $\text{Ti}\left(s\right)+xs{\text{F}}_{2}\left(g\right)\phantom{\rule{0.2em}{0ex}}⟶$

(a) $\text{Fe}\left(s\right)+2{\text{H}}_{3}{\text{O}}^{\text{+}}\left(aq\right)+{\text{SO}}_{4}{}^{2-}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{Fe}}^{2+}\left(aq\right)+{\text{SO}}_{4}{}^{2-}\left(aq\right)+{\text{H}}_{2}\left(g\right)+2{\text{H}}_{2}\text{O}\left(l\right);$ (b) ${\text{FeCl}}_{3}\left(aq\right)+{\text{3Na}}^{\text{+}}\left(aq\right)+{\text{3OH}}^{\text{−}}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\text{Fe}{\left(\text{OH}\right)}_{3}\left(s\right)+{\text{3Na}}^{\text{+}}\left(aq\right)+{\text{3Cl}}^{\text{+}}\left(aq\right);$ (c) $\text{Mn}{\left(\text{OH}\right)}_{2}\left(s\right)+2{\text{H}}_{3}{\text{O}}^{\text{+}}\left(aq\right)+{\text{2Br}}^{\text{−}}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{Mn}}^{2+}\left(aq\right)+{\text{2Br}}^{\text{−}}\left(aq\right)+4{\text{H}}_{2}\text{O}\left(l\right);$ (d) $\text{4Cr}\left(s\right)+3{\text{O}}_{2}\left(g\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}2{\text{Cr}}_{2}{\text{O}}_{3}\left(s\right);$ (e) ${\text{Mn}}_{2}{\text{O}}_{3}\left(s\right)+6{\text{H}}_{3}{\text{O}}^{\text{+}}\left(aq\right)+{\text{6Cl}}^{\text{−}}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}2{\text{MnCl}}_{3}\left(s\right)+9{\text{H}}_{2}\text{O}\left(l\right);$ (f) $\text{Ti}\left(s\right)+xs{\text{F}}_{2}\left(g\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{TiF}}_{4}\left(g\right)$

Describe the electrolytic process for refining copper.

Predict the products of the following reactions and balance the equations.

(a) Zn is added to a solution of Cr 2 (SO 4 ) 3 in acid.

(b) FeCl 2 is added to a solution containing an excess of ${\text{Cr}}_{2}{\text{O}}_{7}{}^{2-}$ in hydrochloric acid.

(c) Cr 2+ is added to ${\text{Cr}}_{2}{\text{O}}_{7}{}^{2-}$ in acid solution.

(d) Mn is heated with CrO 3 .

(e) CrO is added to 2HNO 3 in water.

(f) FeCl 3 is added to an aqueous solution of NaOH.

(a)
$\begin{array}{}\\ \\ {\text{Cr}}_{2}{\left({\text{SO}}_{4}\right)}_{3}\left(aq\right)+\text{2Zn}\left(s\right)+{\text{2H}}_{3}{\text{O}}^{\text{+}}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{2Zn}}^{2+}\left(aq\right)+{\text{H}}_{2}\left(g\right)+{\text{2H}}_{2}\text{O}\left(l\right)+{\text{2Cr}}^{2+}\left(aq\right)+{\text{3SO}}_{4}{}^{2-}\left(aq\right);\end{array}$ (b) ${\text{4TiCl}}_{3}\left(s\right)+{\text{CrO}}_{4}{}^{2-}\left(aq\right)+{\text{8H}}^{\text{+}}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{4Ti}}^{4+}\left(aq\right)+\text{Cr}\left(s\right)+{\text{4H}}_{2}\text{O}\left(l\right)+{\text{12Cl}}^{\text{−}}\left(aq\right);$ (c) In acid solution between pH 2 and pH 6, ${\text{CrO}}_{4}{}^{2-}$ forms ${\text{HCrO}}_{4}{}^{\text{−}},$ which is in equilibrium with dichromate ion. The reaction is ${\text{2HCrO}}_{4}{}^{\text{−}}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{Cr}}_{2}{\text{O}}_{7}{}^{2-}\left(aq\right)+{\text{H}}_{2}\text{O}\left(l\right).$ At other acidic pHs, the reaction is ${\text{3Cr}}^{2+}\left(aq\right)+{\text{CrO}}_{4}{}^{2-}\left(aq\right)+{\text{8H}}_{3}{\text{O}}^{\text{+}}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{4Cr}}^{3+}\left(aq\right)+{\text{12H}}_{2}\text{O}\left(l\right);$ (d) ${\text{8CrO}}_{3}\left(s\right)+\text{9Mn}\left(s\right)\phantom{\rule{0.2em}{0ex}}\stackrel{\text{Δ}}{⟶}\phantom{\rule{0.2em}{0ex}}{\text{4Cr}}_{2}{\text{O}}_{3}\left(s\right)+{\text{3Mn}}_{3}{\text{O}}_{4}\left(s\right);$ (e) $\text{CrO}\left(s\right)+{\text{2H}}_{3}{\text{O}}^{\text{+}}\left(aq\right)+{\text{2NO}}_{3}{}^{\text{−}}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{Cr}}^{2+}\left(aq\right)+{\text{2NO}}_{3}{}^{\text{−}}\left(aq\right)+{\text{3H}}_{2}\text{O}\left(l\right);$ (f) ${\text{CrCl}}_{3}\left(s\right)+\text{3NaOH}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}\text{Cr}{\left(\text{OH}\right)}_{3}\left(s\right)+{\text{3Na}}^{\text{+}}\left(aq\right)+{\text{3Cl}}^{\text{−}}\left(aq\right)$

What is the gas produced when iron(II) sulfide is treated with a nonoxidizing acid?

Predict the products of each of the following reactions and then balance the chemical equations.

(a) Fe is heated in an atmosphere of steam.

(b) NaOH is added to a solution of Fe(NO 3 ) 3 .

(c) FeSO 4 is added to an acidic solution of KMnO 4 .

(d) Fe is added to a dilute solution of H 2 SO 4 .

(e) A solution of Fe(NO 3 ) 2 and HNO 3 is allowed to stand in air.

(f) FeCO 3 is added to a solution of HClO 4 .

(g) Fe is heated in air.

(a) $\text{3Fe}\left(s\right)+{\text{4H}}_{2}\text{O}\left(g\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{Fe}}_{3}{\text{O}}_{4}\left(s\right)+{\text{4H}}_{2}\left(g\right);$ (b) $\text{3NaOH}\left(aq\right)+\text{Fe}{\left({\text{NO}}_{3}\right)}_{3}\left(aq\right)\phantom{\rule{0.2em}{0ex}}\stackrel{\phantom{\rule{0.5em}{0ex}}{\text{H}}_{2}\text{O}\phantom{\rule{0.5em}{0ex}}}{\to }\phantom{\rule{0.2em}{0ex}}\text{Fe}{\left(\text{OH}\right)}_{3}\left(s\right)+{\text{3Na}}^{\text{+}}\left(aq\right)+3{\text{NO}}_{3}{}^{\text{−}}\left(aq\right);$ (c) $\begin{array}{}\\ \\ \\ \text{MnO}{}^{4-}+5\text{Fe}{\text{2+}}^{}+8\text{H}{\text{+}}^{}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}\text{Mn}{}^{\text{2+}}+5{\text{Fe}}_{3}+4{\text{H}}_{2}\text{O}\end{array};$ (d) $\text{Fe}\left(s\right)+{\text{2H}}_{3}{\text{O}}^{\text{+}}\left(aq\right)+{\text{SO}}_{4}{}^{2-}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{Fe}}^{2+}\left(aq\right)+{\text{SO}}_{4}{}^{2-}\left(aq\right)+{\text{H}}_{2}\left(g\right)+{\text{2H}}_{2}\text{O}\left(l\right);$ (e) ${\text{4Fe}}^{2+}\left(aq\right)+{\text{O}}_{2}\left(g\right)+{\text{4HNO}}_{3}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{4Fe}}^{3+}\left(aq\right)+{\text{2H}}_{2}\text{O}\left(l\right)+{\text{4NO}}_{3}{}^{\text{−}}\left(aq\right);$ (f) ${\text{FeCO}}_{3}\left(s\right)+{\text{2HClO}}_{4}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}\text{Fe}{\left({\text{ClO}}_{4}\right)}_{2}\left(aq\right)+{\text{H}}_{2}\text{O}\left(l\right)+{\text{CO}}_{2}\left(g\right);$ (g) $\text{3Fe}\left(s\right)+{\text{2O}}_{2}\left(g\right)\phantom{\rule{0.2em}{0ex}}\stackrel{\phantom{\rule{0.2em}{0ex}}\text{Δ}\phantom{\rule{0.2em}{0ex}}}{⟶}\phantom{\rule{0.2em}{0ex}}{\text{Fe}}_{3}{\text{O}}_{4}\left(s\right)$

Balance the following equations by oxidation-reduction methods; note that three elements change oxidation state.
$\text{Co}{\left({\text{NO}}_{3}\right)}_{2}\left(s\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{Co}}_{2}{\text{O}}_{3}\left(s\right)+{\text{NO}}_{2}\left(g\right)+{\text{O}}_{2}\left(g\right)$

Dilute sodium cyanide solution is slowly dripped into a slowly stirred silver nitrate solution. A white precipitate forms temporarily but dissolves as the addition of sodium cyanide continues. Use chemical equations to explain this observation. Silver cyanide is similar to silver chloride in its solubility.

${\text{Ag}}^{\text{+}}\left(aq\right)+{\text{CN}}^{\text{−}}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}\text{AgCN}\left(s\right)$
$\begin{array}{l}{\text{Ag}}^{\text{+}}\left(aq\right)+2{\text{CN}}^{\text{−}}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\left[\text{Ag}{\text{(CN)}}_{2}\right]}^{\text{−}}\left(aq\right)\\ \text{AgCN}\left(s\right)+{\text{CN}}^{\text{−}}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\left[\text{Ag}{\text{(CN)}}_{2}\right]}^{\text{−}}\left(aq\right)\end{array}$

Predict which will be more stable, [CrO 4 ] 2− or [WO 4 ] 2− , and explain.

Give the oxidation state of the metal for each of the following oxides of the first transition series. (Hint: Oxides of formula M 3 O 4 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·M 2 O 3 , to permit estimation of the metal’s two oxidation states.)

(a) Sc 2 O 3

(b) TiO 2

(c) V 2 O 5

(d) CrO 3

(e) MnO 2

(f) Fe 3 O 4

(g) Co 3 O 4

(h) NiO

(i) Cu 2 O

(a) Sc 3+ ; (b) Ti 4+ ; (c) V 5+ ; (d) Cr 6+ ; (e) Mn 4+ ; (f) Fe 2+ and Fe 3+ ; (g) Co 2+ and Co 3+ ; (h) Ni 2+ ; (i) Cu +

what does nano mean?
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
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Daniel
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it is a goid question and i want to know the answer as well
Maciej
Abigail
for teaching engĺish at school how nano technology help us
Anassong
Do somebody tell me a best nano engineering book for beginners?
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are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
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Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
so some one know about replacing silicon atom with phosphorous in semiconductors device?
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
for screen printed electrodes ?
SUYASH
What is lattice structure?
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
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what is biological synthesis of nanoparticles
what's the easiest and fastest way to the synthesize AgNP?
China
Cied
types of nano material
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Porter
many many of nanotubes
Porter
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what is the function of carbon nanotubes?
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I'm interested in nanotube
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preparation of nanomaterial
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Jordan
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Jordan
what chemical
Jordan
how did you get the value of 2000N.What calculations are needed to arrive at it
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