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4 years ago

When balancing a redox reaction, you are balancing

Chemistry

2 answers:

marshall27 [118]4 years ago

5 0

Hope this helped you :)

prisoha [69]4 years ago

4 0

Answer:

D. Both A and C

Explanation:

When balancing a redox equation, you'll first of all check for the oxidation equation, balance the number of moles and then the charges and move next to reduction equation and do the same. Then add up both half-equations to give the overall redox equation. The subscripts on each molecule isn't really required separately since they'll be balanced during the half equations.

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What is the molarity of a solution composed of 4.73 g of potassium iodide (KI) dissolved in enough water to make 0.169 L of solu

Kazeer [188]

Answer:

[KI] = 0.17 M

Explanation:

We determine the moles of solute:

Mass / Molar mass → 4.73 g / 166 g/mol = 0.0285 moles

Molarity (mol/L) is defined as moles of solute in 1L of solution

It is a sort of concentration

M = 0.0285 mol / 0.169L = 0.17 M

Instead of making the division (mol/L), we can also try this rule of three:

In 0.169 L we have 0.0285 moles of solute

in 1 L we must have ___ (1 . 0.0285) / 0.169 = 0.17 mol/L

4 0

3 years ago

"Thermite" reactions have been used for welding metal parts such as railway rails and in metal refining. One such thermite react

frosja888 [35]

Answer: The given reaction is non-spontaneous in nature.

Explanation:

Entropy change is defined as the difference in entropy of all the product and the reactants each multiplied with their respective number of moles.

The equation used to calculate entropy change is of a reaction is:

$\Delta S^o_{rxn}=\sum [n\times \Delta S^o_{(product)}]-\sum [n\times \Delta S^o_{(reactant)}]$

For the given chemical reaction:

$3Mg(s)+Cr_2O_3(s)\rightarrow 3MgO(s)+2Cr(s)$

The equation for the entropy change of the above reaction is:

$\Delta S^o_{rxn}=[(3\times \Delta S^o_{(MgO(s))})+(2\times \Delta S^o_{(Cr(s))})]-[(3\times \Delta S^o_{(Mg(s))})+(1\times \Delta S^o_{(Cr_2O_3(s))})]$

We are given:

$\Delta S^o_{(Mg(s))}=32.68J/K.mol\\\Delta S^o_{(Cr_2O_3(s))}=81.2J/K.mol\\\Delta S^o_{(MgO(s))}=26.94J/K.mol\\\Delta S^o_{(Cr(s))}=23.77J/K.mol$

Putting values in above equation, we get:

$\Delta S^o_{rxn}=[(3\times (26.94))+(2\times (23.77))]-[(3\times (32.68))+(1\times (81.2))]\\\\\Delta S^o_{rxn}=-50.88J/K=-0.0509kJ/K.mol$

For the reaction to be spontaneous, the Gibbs free energy of the reaction must come out to be negative.

To calculate the standard Gibbs free energy of the reaction, we use the equation:

$\Delta G^o=\Delta H^o-T\Delta S^o$

where,

$\Delta G^o$ = standard Gibbs free energy = ?

$\Delta H^o$ = standard enthalpy change of the reaction = 665.1 kJ/mol

T = Temperature = 298.15 K

$\Delta S^o$ = standard entropy change of the reaction = -0.0509 kJ/K.mol

Putting values in above equation, we get:

$\Delta G^o=(665.1kJ/mol)-(298.15K\times (-0.0509kJ/K.mol))=680.27kJ/mol$

As, the Gibbs free energy of the reaction is coming out to be positive, the reaction is non-spontaneous in nature.

Hence, the given reaction is non-spontaneous in nature.

4 0

4 years ago

Today is October 31 and we view or third quarter on what date did we reserve the last new moon

Mrrafil [7]

Answer: March 21

Explanation: March 21

6 0

4 years ago

Balance the equations by inserting coefficients as needed. CaH₂ + H₂O Ca(OH)₂ + H₂

dmitriy555 [2]

The balanced equation is $CaH_{2} + 2 H_{2} O = Ca(OH)_{2} + 2 H_{2}$ .

The above equation is a redox reaction. A chemical equation is said to be balanced when the total mass of atoms on the reactant and product side are equal. This means that the number of atoms on both side must also be equal.

We have, $CaH_{2} + H_{2} O = Ca(OH)_{2} + H_{2}$ .

The number of atoms of Calcium (one on both sides) and Hydrogen(four on both sides) are equal. Whereas, there are 2 atoms of Oxygen on the right-hand side and only 1 atom of Oxygen on the left-hand side. So, we can put the coefficient of 2 on the molecule that has Oxygen on the left-hand side to balance them out. i.e.,

$CaH_{2} + 2H_{2} O = Ca(OH)_{2} + H_{2}$

Now, there are 6 atoms of Hydrogen on the left-hand side but only 4 on the right-hand side. To balance this, we can put the coefficient of 2 on the Hydrogen molecule on the right-hand side.

Thus, we get the final balanced equation as : $CaH_{2} + 2 H_{2} O = Ca(OH)_{2} + 2 H_{2}$

To read about balancing chemical equations visit brainly.com/question/11904811

4 0

2 years ago

How did the US government change its policy toward Native American land during the 1850s?

Tju [1.3M]

Answer:

The correct answer is B) They created new treaties and reservations that defined specific boundaries for each tribe

Explanation:

One of such acts which was used to reallocate the Native American Land was the General Allotment (Dawes) Act of 1887.

It gave permission to the Federal Government to modify the size and ownership structure of land belonging to the Native Americans. The end result was that the total amount of land originally belonging to the Native Americans reduced drastically over the next 500 years.

Cheers!

4 0

4 years ago