........PLEASE HELP........

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

Compare the intermolecular forces, dipole-dipole and hydrogen-bonding. What would you suggest is the biggest different between t

Angelina_Jolie [31]

Both the dipole-dipole and hydrogen are essentially same because they result form formation of partial negative and positive charges on the atoms constituting a given molecule. in such molecule, one atom is more electronegative than the other and therefore pulls the shared electrons more to itself than the other atom. the atom that pulls a pair of electrons more to itself becomes partially negatively charged whereas the other atom becomes partially positively charge. the weak negative charges on one molecule attracts weak positive charge on the other molecule creating intermolecular forces referred to as dipole-dipole bonds. Hydrogen bonds form in the same manner they are stronger than typical dipole-dipole bonds. so according to the explanation above D is the correct answer.

6 0

3 years ago

After Frank Palko was sentenced to death by the state of Connecticut, the Supreme Court ruled that

GREYUIT [131]

<span>The answer is "his conviction and execution should be upheld". Frank Palko was first charged with murder and claimed that Connecticut violated the Double Jeopardy Clause of the Fifth Amendment. The fifth amendment states that "there must be no person to be put twice in jeopardy of life and limb" so this was the violation the court made after they charge him with murder for the second time. That's why when the second trial was made,he was sentenced to by the Supreme court which decided that he should be executed and convicted because of the evidences found.</span>

4 0

3 years ago

Read 2 more answers

You come across a thick deposit of shale that forms a layer in the ground. What can u infer about the area’s past environment

kirill [66]

The environment would have most likely been covered in deep water such as in a lake or swamp. One with clay particle and other fine particle sediments.

4 0

3 years ago

Read 2 more answers

How many electrons can each individual orbital hold?

Hatshy [7]

Answer:

Orbitals of equal energy are each occupied by one electron before any orbital is occupied by a second electron, and all electrons in singly occupied orbitals must have the same spin state. Noble-gas configuration refers to an outer main energy level occupied, in most cases, by eight electrons.

Explanation:

I hope this helps you.

3 0

3 years ago

Read 2 more answers