The standard enthalpy of formation of a free element in its standard

A Cu2+ solution is prepared by dissolving a 0.4749 g piece of copper wire in acid. The solution is then passed through a Walden

Luda [366]

Answer:

Concentration of $Cr_2O_7^{2-}$ = 0.03101 M

Concentration of $MnO_4^-$ = 0.03721 M

Explanation:

A)

The reduction for $Cr_2O_7^{2-}$ is;

$Cr_2O_7^{2-} + 14 H ^+ _{(aq)} + 6 e^- -----> 2 Cr^{3+} _{(aq)}+7H_2O _{(l)}$

$Cu^+_{(aq)} -----> Cu^{2+} _{(aq)} + 1 e^-$

6 moles of $Cu ^+$ = 1 mole of $Cr_2O_7^{2-}$

number of moles of Cu reacted = $\frac{mass \ of \ Cu \ wire }{ molecular weigh tof \ Cu wire }$

number of moles of Cu reacted = $\frac{0.4749}{63.55}$

number of moles of Cu reacted = 0.00747 mole

number of moles of $Cr_2O_7^{2-}$ reacted = $\frac{0.00747}{6}$

number of moles of $Cr_2O_7^{2-}$ reacted = 0.001245 mole

Concentration of $Cr_2O_7^{2-}$ = $\frac{number \ of moles }{Volume}$

Given that the volume = 40.15 mL = $40.15 *10^{-3}$ ; we have:

Concentration of $Cr_2O_7^{2-}$ = $\frac{0.001245}{40.15*10^{-3}}$

Concentration of $Cr_2O_7^{2-}$ = 0.03101 M

B)

The reduction for $MnO_4^-$ is;

$MnO_4^- + 8H^+ + 5 e^- -----> Mn^{2+} + 4H_2O$

$Cu^+_{(aq)} -----> Cu^{2+} _{(aq)} + 1 e^-$

5 moles of $Cu ^+$ = 1 mole of $Cr_2O_7^{2-}$

number of moles of Cu reacted = $\frac{mass \ of \ Cu \ wire }{ molecular weigh tof \ Cu wire }$

number of moles of Cu reacted = $\frac{0.4749}{63.55}$

number of moles of Cu reacted = 0.00747 mole

number of moles of $MnO_4^-$ reacted = $\frac{0.00747}{5}$

number of moles of $MnO_4^-$ reacted = 0.001494 mole

Concentration of $MnO_4^-$ = $\frac{number \ of moles }{Volume}$

Given that the volume = 40.15 mL = $40.15 *10^{-3}$ ; we have:

Concentration of $MnO_4^-$ = $\frac{0.001494 }{40.15*10^{-3}}$

Concentration of $MnO_4^-$ = 0.03721 M

3 0

4 years ago

11. What is the mole ratio of C to B in the following generic chemical reaction?2A + 3B → C + 4D (correct numbers 1 point, corre

krok68 [10]

Is this for the honors unit 6 chem test?

4 0

3 years ago

A sample of Br 2 ( g ) Br2(g) takes 42.0 min 42.0 min to effuse through a membrane. How long would it take the same number of mo

Simora [160]

15 mins

~Savannah

Jokes from Savannah~

A man goes to the doctor, concerned about his wife’s hearing. The doctor says, “Stand behind her and say something and tell me how close you are when she hears you.”

The man goes home, sees his wife in the kitchen, cutting carrots on the countertop. About 15 feet away he says, “Honey, what’s for dinner?” Nothing. He gets halfway to her and repeats the same question. Nothing. Very concerned, he gets right behind her and asks again “What’s for dinner?”

She turns around and says “For the THIRD time, beef stew!”

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Q: What do you get when you cross a vampire with a snowman?

A: Frostbite!

6 0

3 years ago

Show work please osososs

Ilia_Sergeevich [38]

Bskbshsisbusvsuvshvsudvudvdvduvdudbidhdudvubdjdufvdvgdgdhdhfjfufkfkjffjfhfhfb

8 0

3 years ago

The Process of forming a new<br> eukaryotic cell is called

gulaghasi [49]

Answer:

Mitosis I think

Explanation:

4 0

3 years ago