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3 years ago

The chemical equation for a reaction between K2Cr2O7 and HCl is shown.

Chemistry

2 answers:

Semmy [17]3 years ago

4 0

Answer:

K2Cr2O7, because the oxidation number of Cr changes from +6 to +3.

Explanation:

took the test

deff fn [24]3 years ago

3 0

K2Cr2O7 + 14HCl → 2CrCl3 + 2KCl + 3Cl2 + 7H2O

the correct option is :

K2Cr2O7, because the oxidation number of Cr changes from +6 to +3.

Oxidation number of Cr in K2Cr2O7 is:

K2Cr2O7 = 2K + 2 Cr + 7 O

= 2(+1) + 2Cr + 7(-2)

= 2 + 2Cr -14

[total charge on K2Cr2O7 = 0], Hence;

2 + 2Cr -14 = 0

2Cr -12 = 0

2Cr = 12

Cr = 12/2

Cr = +6

Oxidation number of Cr in CrCl3 is:

CrCl3 = Cr + 3Cl = 0

Cr + 3(-1) = 0

Cr -3 = 0

Cr = +3

Hence Cr is changing its oxidation number from

+6 in K2Cr2O7 to +3 in CrCl3.

Since the oxidation number of Cr [ +6 → +3] is decreasing here,

Cr is getting reduced.

so K2Cr2O7 is an oxidizing agent,as it is getting itself reduced and oxidizes others.

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Answer A B C and D please for my chemistry hw

r-ruslan [8.4K]

Answer: The equations are provided below.

Explanation:

Skeleton equations are defined as the equations which simply indicate the molecules that are involved in a chemical reaction. These equations are unbalanced equations.

Balanced equations are defined as the chemical equation in which number of individual atoms on the reactant side must be equal to the number of individual atoms on the product side.

For A:

Water decomposes in the direct current to form hydrogen and oxygen.

Skeleton Equation: $H_2O(l)\rightarrow H_2(g)+O_2(g)$

Balanced Equation: $2H_2O(l)\rightarrow 2H_2(g)+O_2(g)$

For B:

Mercury (II) oxide decomposes in heat to form mercury, oxygen.

Skeleton Equation: $HgO(s)\rightarrow Hg+O_2$

Balanced Equation: $2HgO(s)\rightarrow 2Hg+O_2$

For C:

Calcium carbonate when heated forms calcium oxide and carbon dioxide.

Skeleton Equation: $CaCO_3(s)\rightarrow CaO(s)+CO_2(g)$

Balanced Equation: $CaCO_3(s)\rightarrow CaO(s)+CO_2(g)$

For D:

Group 2 hydroxides, when heated forms oxide and water vapor.

Skeleton Equation: $Ca(OH)_2\rightarrow CaO+H_2O$

Balanced Equation: $Ca(OH)_2\rightarrow CaO+H_2O$

3 0

3 years ago

Isotopes do not have the same number of which of these?

Sindrei [870]

Isotopes are basically from the same element. In terms of subatomic particles of the element, the isotopes will then basically have the same number of protons. The electrons also have to be same in number given that the elements are in neutral charges.

We are then left with neutrons, which is one of the subatomic particles residing in the nucleus of an atom.

Thus, the answer is NEUTRONS.

3 0

3 years ago

Read 2 more answers

If a house viewed through infrared goggles ,where would the most seen

Serjik [45]

Answer:

The answer is D - near the roof.

Explanation:

Attics don't have a ton of insulation or hard cinder-block to block the goggles form seeing through it. This is why the attic can be a place where the temperature varies with the outside temperature.

5 0

3 years ago

3. Which of the following is NOT a major ingredient in weather?

belka [17]

Explanation: B Sunshine

4 0

3 years ago

Read 2 more answers

What is that the theoretical yield of aluminum oxide I if 3.20 mol of aluminum metal is exposed to 2.70 mole of oxygen

photoshop1234 [79]

Answer:

163.2g

Explanation:

First let us generate a balanced equation for the reaction. This is shown below:

4Al + 3O2 —> 2Al2O3

From the question given, were were told that 3.2moles of aluminium was exposed to 2.7moles of oxygen. Judging by this, oxygen is excess.

From the equation,

4moles of Al produced 2moles of Al2O3.

Therefore, 3.2moles of Al will produce = (3.2x2)/4 = 1.6mol of Al2O3.

Now, let us covert 1.6mol of Al2O3 to obtain the theoretical yield. This is illustrated below:

Mole of Al2O3 = 1.6mole

Molar Mass of Al2O3 = (27x2) + (16x3) = 54 + 48 =102g/mol

Mass of Al2O3 =?

Number of mole = Mass /Molar Mass

Mass = number of mole x molar Mass

Mass of Al2O3 = 1.6 x 102 = 163.2g

Therefore the theoretical of Al2O3 is 163.2g

8 0

3 years ago