<< Chapter < Page Chapter >> Page >

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%

Got questions? Get instant answers now!

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.

Got questions? Get instant answers now!

Find the potentials of the following electrochemical cell:

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

0.167 V

Got questions? Get instant answers now!

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?

Got questions? Get instant answers now!

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

Got questions? Get instant answers now!

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 )

Got questions? Get instant answers now!

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 )

Got questions? Get instant answers now!

Describe the electrolytic process for refining copper.

Got questions? Get instant answers now!

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 )

Got questions? Get instant answers now!

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

Got questions? Get instant answers now!

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 )

Got questions? Get instant answers now!

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 )

Got questions? Get instant answers now!

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 )

Got questions? Get instant answers now!

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

Got questions? Get instant answers now!

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 +

Got questions? Get instant answers now!

Questions & Answers

What is whizatron?
Frendick Reply
What is stoichometry
ngwuebo Reply
what is atom
yinka Reply
An indivisible part of an element
ngwuebo
the smallest particle of an element which is indivisible is called an atom
Aloaye
An atom is the smallest indivisible particle of an element that can take part in chemical reaction
Alieu
is carbonates soluble
Ebuka Reply
what is the difference between light and electricity
Joshua Reply
What is atom? atom can be defined as the smallest particles
Adazion
what is the difference between Anode and nodes?
Adazion
What's the net equations for the three steps of dissociation of phosphoric acid?
Lisa Reply
what is chemistry
Prince Reply
the study of matter
Reginald
what did the first law of thermodynamics say
Starr Reply
energy can neither be created or distroyed it can only be transferred or converted from one form to another
Adedeji
Graham's law of Diffusion
Ayo Reply
what is melting vaporization
Anieke Reply
melting and boiling point explain in term of molecular motion and Brownian movement
Anieke
Scientific notation for 150.9433962
Steve Reply
what is aromaticity
Usman Reply
aromaticity is a conjugated pi system specific to organic rings like benzene, which have an odd number of electron pairs within the system that allows for exceptional molecular stability
Pookieman
what is caustic soda
Ogbonna Reply
sodium hydroxide (NaOH)
Kamaluddeen
what is distilled water
Rihanat
is simply means a condensed water vapour
Kamaluddeen
advantage and disadvantage of water to human and industry
Abdulrahman Reply
a hydrocarbon contains 7.7 percent by mass of hydrogen and 92.3 percent by mass of carbon
Timothy Reply

Get the best Chemistry course in your pocket!





Source:  OpenStax, Chemistry. OpenStax CNX. May 20, 2015 Download for free at http://legacy.cnx.org/content/col11760/1.9
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Chemistry' conversation and receive update notifications?

Ask