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Wittaler [7]
3 years ago
15

Select the correct balanced oxidation-reduction reaction. Group of answer choices 14H+(aq) + 6Fe2+(aq) + Cr2O72-(aq) -> 6Fe3+

(aq) + 2Cr +(aq) + 7H2O(l) 14H+(aq) + 6Fe2+(aq) + Cr2O72-(aq) -> 6Fe3+(aq) + 2Cr3+(aq) + 7H2O(l) + 2e- 7H+(aq) + 6Fe2+(aq) + Cr2O72-(aq) -> 6Fe3+(aq) + 2Cr3+(aq) + 7H2O(l) 14H+(aq) + 6Fe2+(aq) + Cr2O72-(aq) -> 6Fe3+(aq) + 2Cr3+(aq) + 7H2O(l)
Chemistry
1 answer:
bezimeni [28]3 years ago
6 0

Answer:

The correct balanced oxidation- reduction reaction is:

14H+(aq) + 6Fe2+(aq) + Cr2O72-(aq) -> 6Fe3+(aq) + 2Cr3+(aq) + 7H2O(l)

Explanation:

In this reaction, iron (Fe2+) is the reducing agent while Cr2O7^2- is the oxidizing agent.

The ion transfer is represented as shown below:

6 Fe 2+  - 6e- -----------> 6 Fe 3+          (oxidation)

2 Cr^6  + 6e^-  ----------> 2 Cr^3           (reduction)

From the unbalanced reaction

Fe2+ + Cr2O72- + H+ ---------->  Fe3+ + Cr3+ + H2O we will follow these steps to balance the reaction.

Step 1: break the equation into two half reactions stating which is oxidized and reduced.

Step 2: Balance the atoms on each sides; the hydrogen, oxygen

Step 3: Balance the gain also

Step 4: Give the electron gained on one side to be equal to the electron lost on the other side.

Step 5: Add the two half reactions and simplify the equation.

Doing this, we obtain

14H+(aq) + 6Fe2+(aq) + Cr2O72-(aq) -> 6Fe3+(aq) + 2Cr3+(aq) + 7H2O(l)

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The activation barrier for the hydrolysis of sucrose into glucose and fructose is 108 kj/mol. If an enzyme increases the rate of
Contact [7]

Answer:

The answer to the question is

If an enzyme increases the rate of the hydrolysis reaction by a factor of 1 million the activation barrier has to be 34.229 kJ lower when sucrose is in the active site of the enzyme

Explanation:

To solve the question we note that Arrhenius's equation for the rate constant is given by

k = Ae^{\frac{-E_{a} }{RT} }

Therefore we have for the un-catalyzed reaction

k = Ae^{\frac{-108000 }{(8.314)(298)} } = A ×1.171 ×10⁻¹⁹ s⁻¹

When an enzyme is added the rate of hydrolysis increases by a factor of 1 million therefore

new rate = initial rate × 1000000 =  A ×1.171 ×10⁻¹⁹ s⁻¹ ×100000 = A ×1.171 ×10⁻¹³ s⁻¹

Hence we have the new given by

k_{new}  = Ae^{\frac{-E_{a(new)} }{RT} } since A,  R and T remain constant

The above relation becomes

A ×1.171 ×10⁻¹³ s⁻¹  = Ae^{\frac{-E_{a(new)}  }{(8.314)(298)} }   which is the same as

1.171 ×10⁻¹³ s⁻¹  = e^{\frac{-E_{a(new)}  }{(8.314)(298)} } that is ㏑(1.171 ×10⁻¹³ ) = {\frac{-E_{a(new)}  }{(8.314)(298)} }

or  Eₐ = 29.8 × 8.314 × 298 = 73771.1 J = 73.7711 kJ

This means that the activation energy barrier needs to be 73.7711 kJ or (108000 J - 73771.1 J), 34228.9 J lower

The activation energy needs to be 34.229 kJ lower.

3 0
4 years ago
At 298K, the equilibrium constant for the following reaction is 4.20×10-7: H2CO3(aq) + H2O H3O+(aq) + HCO3-(aq) The equilibrium
Alex777 [14]

Answer:

The correct answer is 2.016 x 10⁻¹⁷

Explanation:

We have the following chemical reactions and their equilibrium constants (K):

(1) H₂CO₃(aq) + H₂O ⇒ H₃O⁺(aq) + HCO₃⁻(aq)  K₁= 4.20×10⁻⁷

(2) HCO₃⁻(aq) + H₂O ⇒ H₃O⁺(aq) + CO₃²⁻(aq)    K₂= 4.80×10⁻¹¹

And we have to obtain K for the following reaction:

H₂CO₃(aq) + 2H₂O ⇒ 2H₃O⁺(aq) + CO₃²⁻(aq)

If we add equations (1) and (2) we obtain the the desired equation. Remember that when we add chemical equations, the global equilibrium constant is the product of the constants.

H₂CO₃(aq) + H₂O ⇒ H₃O⁺(aq) + <em><u>HCO₃⁻(aq)</u></em>     K₁= 4.20×10⁻⁷

+

<em><u>HCO₃⁻(aq)</u></em> + H₂O ⇒ H₃O⁺(aq) + CO₃²⁻(aq)      K₂= 4.80×10⁻¹¹

-------------------------------------------------------------

H₂CO₃(aq) + 2H₂O ⇒ 2H₃O⁺(aq) + CO₃²⁻(aq)    K= K₁ x K₂

K = K₁ x K₂ = (4.20×10⁻⁷) x (4.80×10⁻¹¹) = 2.016 x 10⁻¹⁷

6 0
3 years ago
Join my Kahoo t<br> Pin-04454287<br><br> join if u like anime
aniked [119]

Answer:

okayy

Explanation:

5 0
3 years ago
How many liters of a 0.5 m sodium hydroxide solution would contain 2 moles of solute?
Klio2033 [76]

Answer:

  • 4 liters

Explanation:

<u>1) Data:</u>

a) M = 0.5 M

<u>Note</u>: since the question is about volume (liters) and moles of solute, the correct unit for the concentration of the hydroxide solution is M (upper case) which is the unit for molarity. Lower case m is used for molality, and you cannot calculate the volume of the solution unless you know some other data, e.g. density of the solution.

b) n = 2

c) V (in liters) = ?

<u>2) Formula:</u>

Molarity is the number of moles of solute per liter of solution:

  • M = n / V (in liters)

<u>3) Solution:</u>

a) Clear V from the formula: V (in liters) = M / n

b) Substitute: V (in liters) =  2 moles /  0.5M  = 4 liters ← answer

7 0
3 years ago
What Factors determine surface Gravity?
ddd [48]

Answer: Gravity depends on two main factors.

Explanation: Those factors are mass and distance. I hope this helps!

7 0
3 years ago
Read 2 more answers
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