How many moles of solute are in 5 liters of a 5 M solution?

Write the oxidation and reduction half reactions;

luda_lava [24]

Answer:

a)

$Fe^{2+}$ ⇒ $Fe^{3+}+e^-$

$Br_2+2e^-$ ⇒ $2Br^-$

b)

$Mg$ ⇒ $Mg^{2+}+2e^-$

$Cr^{3+}+e^-$ ⇒ $Cr^{3+}$

Explanation:

A)

Remember that positive number superscripts mean electrons lack and negative numbers mean electrons 'excess' (if we compare it with the neutral element). So, for the case of Fe2+ which is converted to Fe3+, we know that in Fe2+ there is a two electrons lack, while in Fe3+ there is a 3 electrons lack; it means that Fe2+ was converted to Fe3+ but releasing one electron:

$Fe^{2+}$ ⇒ $Fe^{3+}+e^-$

The same analysis is applied to Br2; Br2 is a molecule which is said to have a zero superscript because it is an apolar covalent bond; and it is converted to Br-, which, according to what I wrote above, means that there is a one electron excess. So, Br2 must have received an electron in order to change to Br-; but Br2 can't change to Br- as simple as that because Br2 is a molecule, not an atom; it is a molecule that has two Br atoms, so, Br2 must give two Br- ions as products, but receiving one electron for each one:

$Br_2+2e^-$ ⇒ $2Br^-$

b)

Applying the same, in Mg2+ there is a 2 electrons lack, and in Mg is not electron lack (its superscript is zero), so Mg must have released two electrons in order to change to Mg2+:

$Mg$ ⇒ $Mg^{2+}+2e^-$

Cr3+ has a 3 electrons lack, and Cr2+ a two electrons one, so, Cr3+ must receive an electron to convert to Cr2+:

$Cr^{3+}+e^-$ ⇒ $Cr^{3+}$

3 0

3 years ago

Read 2 more answers

In the laboratory, Austin is given a mixture of iron filings, sand, and salt. To separate the mixture, Austin uses a magnet, boi

Alex_Xolod [135]

Answer:

D

Explanation:

7 0

2 years ago

Read 2 more answers

Consider the generic reaction: 2 A(g) + B(g) → 2 C(g). If a flask initially contains 1.0 atm of A and 1.0 atm of B, what is the

irina1246 [14]

Answer:

b. 1.5 atm.

Explanation:

Hello!

In this case, since the undergoing chemical reaction suggests that two moles of A react with one moles of B to produce two moles of C, for the final pressure we can write:

$P=P_A+P_B+P_C$

Now, if we introduce the stoichiometry, and the change in the pressure $x$ we can write:

$P=1.0-2x+1.0-x+2x$

Nevertheless, since the reaction goes to completion, all A is consumed and there is a leftover of B, and that consumed A is:

$x=\frac{1.0atm}{2}=0.5atm$

Thus, the final pressure is:

$P=1.0-2(0.5)+1.0-(0.5)+2(0.5)\\\\P=1.5atm$

Therefore the answer is b. 1.5 atm.

Best regards!

3 0

2 years ago

The___ of an element is the number of

castortr0y [4]

Answer:atomic mass, neutrons in the nucleus

Explanation: because I remember from when I took honors chemistry last year we learned about this and it’s called the atomic mass when looking at an atom and the neutrons in the nucleus are effected by it.

8 0

2 years ago

What is the reducing agent in the reaction below?

trapecia [35]

Al is the reducing agent.That is answer B is the above answer
Al acts as a strong reducing agent. It reduces crO3 to form cr while Al is oxidized to Al2O3. Al is capable to reduce cr since Al is higher in reactivity series than cr.

8 0

3 years ago