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At a certain temperature, Kc = 0.0500 and ∆H = +39.0 kJ for the reaction below, 2 MgCl2(s) + O2(g) → 2MgO(s) + Cl2(g) Calculate

Minchanka [31]

Explanation:

Since, it is shown that the reaction has been reversed. Therefore, value of $K_{c}$ will become $\frac{1}{K_{c}}$ .

Hence, new $K_{c'} = \frac{1}{K_{c}}$

= $\frac{1}{0.0500}$

= 20

Also, the number of moles of each reactant has been halved. So, $K_{c''}$ for the reaction $MgO(s) + \frac{1}{2}Cl2(g) → MgCl_{2}(s) + \frac{1}{2} O2(g)$ will also get halved.

Therefore, $K_{c''}$ = $K_{c'}$ = $(20)^{0.5}$

= 4.47

As the value of $\Delta H$ is given as +39.0 kJ. So, it means that the reaction is endothermic in nature. So, energy of reactants will be more than the products. Hence, according to Le Chatelier's principle reaction will move in the forward direction.

As a result, $K_{c}$ will also increase with increase in temperature.

6 0

3 years ago

How does a salt bridge improve a battery?

OlgaM077 [116]

Answer:

A. It keeps the electrolyte solutions neutral.

Explanation:

The electrons flow from the anode to the cathode and the problem is that the cathode may become too negative. The purpose of the salt bridge is to maintain charge balance because the electrons are moving from one-half cell to the other.

3 0

2 years ago

In a titration of 47.41 mL of 0.3764 M ammonia with 0.3838 M aqueous nitric acid, what is the pH of the solution when 47.41 mL +

Volgvan

Answer: The pH of the solution is 1.136

Explanation:

To calculate the moles from molarity, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}$

For ammonia:

Molarity of ammonia = 0.3764 M

Volume of ammonia = 47.41 mL = 0.04741 L (Conversion factor: 1 L = 1000 mL)

Putting values in above equation, we get:

$0.3764mol/L=\frac{\text{Moles of ammonia}}{0.04741L}\\\\\text{Moles of ammonia}=0.01784mol$

For nitric acid:

Molarity of nitric acid = 0.3838 M

Volume of ammonia = (47.41 + 10.00) mL = 57.41 mL= 0.05741 L

Putting values in above equation, we get:

$0.3838mol/L=\frac{\text{Moles of nitric acid}}{0.05741L}\\\\\text{Moles of nitric acid}=0.02203mol$

After the completion of reaction, amount of nitric acid remained = 0.022 - 0.0178 = 0.0042 mol

For the reaction of ammonia with nitric acid, the equation follows:

$NH_3+HNO_3\rightarrow NH_4NO_3$

At $t=0$ 0.0178 0.022

Completion 0 0.0042 0.0178

As, the solution of the reaction is made from strong acid which is nitric acid and the conjugate acid of weak base which is ammonia. So, the pH of the reaction will be based totally on the concentration of nitric acid.

To calculate the pH of the reaction, we use the equation:

$pH=-\log[H^+]$

where,

$[H^+]=\frac{0.0042mol}{0.05741L}=0.0731M$

Putting values in above equation, we get:

$pH=-\log(0.0731)\\\\pH=1.136$

Hence, the pH of the solution is 1.136

8 0

2 years ago

Is dissolving salt a chemical change or physical change and why?

Firlakuza [10]

It's a physical change because the composition of the salt hasn't change. Only the change in substance/form has occured. To tell if something has undergone physical change is:

• Melting

• Boiling

• Freezing

• Condensing

• Breaking

• Bending

• Dissolving

• Molecules can change motion and proximity

To tell if something changed chemically:

• Molecules rearrange with other molecules to make new substance

• Can be production of flames

• Color change

• Bubbling/fizzing

• Temp. change

• change in composition

4 0

2 years ago

If the acceleration is 600 m/s/s and the mass is 300 kg, what force is acting on the object?

vampirchik [111]

Explanation:

Acceleration (a) = 600 m/s²

Mass (m) = 300 kg

Force (F) = ?

We know

F = m * a

= 300 * 600

=180000 Newton

The force acting on the object is 18000 Newton.

5 0

2 years ago

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