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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%

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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.

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Find the potentials of the following electrochemical cell:

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

0.167 V

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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?

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The standard reduction potential for the reaction [ Co ( H 2 O ) 6 ] 3+ ( a q ) + e [ Co ( H 2 O ) 6 ] 2+ ( a q ) is about 1.8 V. The reduction potential for the reaction [ Co ( NH 3 ) 6 ] 3+ ( a q ) + e [ Co ( NH 3 ) 6 ] 2+ ( a q ) 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

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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) MnCO 3 ( s ) + HI ( a q )

(b) CoO ( s ) + O 2 ( g )

(c) La ( s ) + O 2 ( g )

(d) V ( s ) + VCl 4 ( s )

(e) Co ( s ) + x s F 2 ( g )

(f) CrO 3 ( s ) + CsOH ( a q )

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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) Fe ( s ) + H 2 SO 4 ( a q )

(b) FeCl 3 ( a q ) + NaOH ( a q )

(c) Mn ( OH ) 2 ( s ) + HBr ( a q )

(d) Cr ( s ) + O 2 ( g )

(e) Mn 2 O 3 ( s ) + HCl ( a q )

(f) Ti ( s ) + x s F 2 ( g )

(a) Fe ( s ) + 2 H 3 O + ( a q ) + SO 4 2− ( a q ) Fe 2+ ( a q ) + SO 4 2− ( a q ) + H 2 ( g ) + 2 H 2 O ( l ) ; (b) FeCl 3 ( a q ) + 3Na + ( a q ) + 3OH ( a q ) Fe ( OH ) 3 ( s ) + 3Na + ( a q ) + 3Cl + ( a q ) ; (c) Mn ( OH ) 2 ( s ) + 2 H 3 O + ( a q ) + 2Br ( a q ) Mn 2+ ( a q ) + 2Br ( a q ) + 4 H 2 O ( l ) ; (d) 4Cr ( s ) + 3 O 2 ( g ) 2 Cr 2 O 3 ( s ) ; (e) Mn 2 O 3 ( s ) + 6 H 3 O + ( a q ) + 6Cl ( a q ) 2 MnCl 3 ( s ) + 9 H 2 O ( l ) ; (f) Ti ( s ) + x s F 2 ( g ) TiF 4 ( g )

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Describe the electrolytic process for refining copper.

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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 Cr 2 O 7 2− in hydrochloric acid.

(c) Cr 2+ is added to Cr 2 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)
Cr 2 ( SO 4 ) 3 ( a q ) + 2Zn ( s ) + 2H 3 O + ( a q ) 2Zn 2+ ( a q ) + H 2 ( g ) + 2H 2 O ( l ) + 2Cr 2+ ( a q ) + 3SO 4 2− ( a q ) ; (b) 4TiCl 3 ( s ) + CrO 4 2− ( a q ) + 8H + ( a q ) 4Ti 4+ ( a q ) + Cr ( s ) + 4H 2 O ( l ) + 12Cl ( a q ) ; (c) In acid solution between pH 2 and pH 6, CrO 4 2− forms HCrO 4 , which is in equilibrium with dichromate ion. The reaction is 2HCrO 4 ( a q ) Cr 2 O 7 2− ( a q ) + H 2 O ( l ) . At other acidic pHs, the reaction is 3Cr 2+ ( a q ) + CrO 4 2− ( a q ) + 8H 3 O + ( a q ) 4Cr 3+ ( a q ) + 12H 2 O ( l ) ; (d) 8CrO 3 ( s ) + 9Mn ( s ) Δ 4Cr 2 O 3 ( s ) + 3Mn 3 O 4 ( s ) ; (e) CrO ( s ) + 2H 3 O + ( a q ) + 2NO 3 ( a q ) Cr 2+ ( a q ) + 2NO 3 ( a q ) + 3H 2 O ( l ) ; (f) CrCl 3 ( s ) + 3NaOH ( a q ) Cr ( OH ) 3 ( s ) + 3Na + ( a q ) + 3Cl ( a q )

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

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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) 3Fe ( s ) + 4H 2 O ( g ) Fe 3 O 4 ( s ) + 4H 2 ( g ) ; (b) 3NaOH ( a q ) + Fe ( NO 3 ) 3 ( a q ) H 2 O Fe ( OH ) 3 ( s ) + 3Na + ( a q ) + 3 NO 3 ( a q ) ; (c) MnO 4− + 5 Fe 2+ + 8 H + Mn 2+ + 5 Fe 3 + 4 H 2 O ; (d) Fe ( s ) + 2H 3 O + ( a q ) + SO 4 2− ( a q ) Fe 2+ ( a q ) + SO 4 2− ( a q ) + H 2 ( g ) + 2H 2 O ( l ) ; (e) 4Fe 2+ ( a q ) + O 2 ( g ) + 4HNO 3 ( a q ) 4Fe 3+ ( a q ) + 2H 2 O ( l ) + 4NO 3 ( a q ) ; (f) FeCO 3 ( s ) + 2HClO 4 ( a q ) Fe ( ClO 4 ) 2 ( a q ) + H 2 O ( l ) + CO 2 ( g ) ; (g) 3Fe ( s ) + 2O 2 ( g ) Δ Fe 3 O 4 ( s )

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Balance the following equations by oxidation-reduction methods; note that three elements change oxidation state.
Co ( NO 3 ) 2 ( s ) Co 2 O 3 ( s ) + NO 2 ( g ) + O 2 ( g )

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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.

As CN is added,
Ag + ( a q ) + CN ( a q ) AgCN ( s )
As more CN is added,
Ag + ( a q ) + 2 CN ( a q ) [ Ag (CN) 2 ] ( a q ) AgCN ( s ) + CN ( a q ) [ Ag (CN) 2 ] ( a q )

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

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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 +

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Questions & Answers

what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
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Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
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Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
bamidele Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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razzyd Reply
A teaspoon of the carbohydrate sucrose contains 16 calories, what is the mass of one teaspoo of sucrose if the average number of calories for carbohydrate is 4.1 calories/g?
ifunanya Reply
4. On the basis of dipole moments and/or hydrogen bonding, explain in a qualitative way the differences in the boiling points of acetone (56.2 °C) and 1-propanol (97.4 °C), which have similar molar masses
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Calculate the bond order for an ion with this configuration: (?2s)2(??2s)2(?2px)2(?2py,?2pz)4(??2py,??2pz)3
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Which of the following will increase the percent of HF that is converted to the fluoride ion in water? (a) addition of NaOH (b) addition of HCl (c) addition of NaF
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Source:  OpenStax, Ut austin - principles of chemistry. OpenStax CNX. Mar 31, 2016 Download for free at http://legacy.cnx.org/content/col11830/1.13
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