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4 years ago

What is E=mc2? please be specific.

1 answer:

4 0

E = mc2 is an equation. E represents units of energy, m represents units of mass and c2 is the speed of light squared or multiplied by itself.

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A chemist designs a galvanic cell that uses these two half-reactions: half-reaction standard reduction potential (s)(aq)(aq)(l)

miv72 [106K]

Answer:

Reduction (cathode): Cu²⁺(⁺aq) + 2 e⁻ → Cu(s)

Oxidation (anode): Zn(s) → Zn²⁺(⁺aq) + 2 e⁻

Cu²⁺(⁺aq) + Zn(s) → Cu(s) + Zn²⁺(⁺aq)

E°cell = 1.10 V

Explanation:

The half-reactions are missing, but I will propose some to show you the general procedure and then you can apply it to your equations.

Suppose we have the following half-reactions.

Cu²⁺(⁺aq) + 2 e⁻ → Cu(s) E°red = 0.34 V

Zn²⁺(⁺aq) + 2 e⁻ → Zn(s) E°red = -0.76 V

To identify how to make a spontaneous cell, we need to consider the standard reduction potentials (E°red). The half-reaction with the higher E°red will occur as a reduction (in the cathode), whereas the one with the lower E°red will occur as an oxidation (in the anode).

Reduction (cathode): Cu²⁺(⁺aq) + 2 e⁻ → Cu(s) E°red = 0.34 V

Oxidation (anode): Zn(s) → Zn²⁺(⁺aq) + 2 e⁻ E°red = -0.76 V

To get the overall equation we add both half-reactions.

Cu²⁺(⁺aq) + Zn(s) → Cu(s) + Zn²⁺(⁺aq)

The standard cell potential (E°cell) is the difference between the standard reduction potential of the cathode and the standard reduction potential of the anode.

E°cell = E°red, cat - E°red, an

E°cell = 0.34 V - (-0.76 V) = 1.10 V

Since E°cell > 0, the reaction is spontaneous.

5 0

3 years ago

Which compound has the highest percent composition by mass of strontium

8090 [49]

So if the compound has the smallest gram formula mass it has the highest percentage composition by mass of strontium

3 0

3 years ago

Consider the given acid ionization constants. identify the strongest conjugate base.

WARRIOR [948]

The question is incomplete. Complete question is:
Consider the given acid ionization constants. identify the strongest conjugate base.
HNO2(aq) 4.6×10−4
HCHO2(aq) 1.8×10−4
HClO(aq) 2.9×10−8
HCN(aq) 4.9×10−10
.........................................................................................................................
Correct Answer: option 4: HCN(aq) 4.9×10−10

Reason:
According to Lowry and Bronsted theory of acid and base. Stronger the acid, weaker will be the conjugate base.

In present case, ionization constant is highest of HCN i.e. 4.9× $10^{-10}$ . This signifies that, it is the strongest acid. Hence, conjugate base associated with this acid (i.e. $CN^{-}$ ) is the weakest.

7 0

4 years ago

Read 2 more answers

1) What mass of Na2CO3 is required to make 50cc of its seminormal solution?

love history [14]

Answer:

$m=1.325gNa_2CO_3$

Explanation:

Hello,

In this case, by considering the given seminormal solution, we infer it is a 0.5-N solution which means that we can obtain the equivalent grams as shown below for the 55 cc (0.055 L) volume:

$eq-g=0.5eq-g/L*0.050L=0.025eq-g$

Next, since sodium carbonate has two sodium ions with a +1 oxidation state each, we can obtain the moles:

$mol=0.025eq-gNa_2CO_3*\frac{1molNa_2CO_3}{2eq-gNa_2CO_3}\\ \\mol=0.0125molNa_2CO_3$

Finally, the mass is computed by using its molar mass (106 g/mol)

$m=0.0125molNa_2CO_3*\frac{106gNa_2CO_3}{1molNa_2CO_3} \\\\m=1.325gNa_2CO_3$

Regards.

7 0

3 years ago

What gas law applies to aerosol cans being stored in a cool place?

svetlana [45]

Don't really know if this is what your asking but P1/T1= P2/T2 should show how the pressure varies with temperature (V is left out because it's constant since the gas is trapped in an aerosol can). As the temperature rises the pressure rises and if it gets too high then the can explodes, which is why it should be stored in a cool place. There's also PV=nRT might be kind of hard to find moles (n) though.

3 0

3 years ago