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4 years ago

8

What should have only one idependent variable

1 answer:

jenyasd209 [6]4 years ago

3 0

I think a controlled experiment

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Which of the following answers below is the correctly balanced half-reaction for the reduction of the SO4 ^-2 ion in acid soluti

Rom4ik [11]

Answer:

C

Explanation:

The oxidation number of Sulphur in SO4^2- is;

x + 4(-2) = -2

x - 8 = -2

x = -2 + 8

x = 6

Now,

the oxidation number of sulphur in H2SO3 is

2 (1) + x + 3(-2) = 0

2 + x -6 = 0

-4 + x = 0

x = 4

Hence, the oxidation number of sulphur changed from +6 to +4 which signifies gain of two electrons as shown in option C.

8 0

3 years ago

Which of the following elements exists as a diatomic molecule? Argon, Hydrogen, Boron, Sulfur

Elis [28]

Diatomic molecules are the molecules that you can find them in natural bonded to itself. example: O₂, N₂ or Br₂.

the answer is hydrogen ---> H₂

I have attached a little trick to remember these.

5 0

3 years ago

[Co(H2O)6]2+(aq) + 4Cl-(aq) ⇌ [CoCl4]2-(aq) + 6H2O(l)

pav-90 [236]

<u>Answer:</u>

<u>For A:</u> The expression for $K_{eq}$ is given below.

<u>For B:</u> The value of $K_{eq}$ at 25°C is 0.0185512

<u>For C:</u> The value of $K_{eq}$ at 65°C is 0.2887886

<u>For D:</u> The reaction is endothermic in nature.

<u>Explanation:</u>

<u>For A:</u>

Equilibrium constant is defined as the ratio of concentration of products to the concentration of reactants each raised to the power their stoichiometric ratios. It is expressed as $K_{eq}$

For the given chemical reaction:

$[Co(H_2O)_6]^{2+}(aq.)+4Cl^-(aq.)\rightleftharpoons [CoCl_4]^{2-}(aq.)+6H_2O(l)$

The expression of $K_{eq}$ for above equation without the concentration of liquid water is:

$K_{eq}=\frac{[CoCl_4]^{2-}}{[Co(H_2O)_6]^{2+}[Cl^-]^4}$ ......(1)

The expression is written above.

<u>For B:</u>

We are given:

$[CoCl_4]^{2-}=0.0334612M$

$[Co(H_2O)_6]^{2+}=0.966539M$

$[Cl^-]=1.86616M$

Putting values in equation 1, we get:

$K_{eq}=\frac{0.0334612}{0.966539\times 1.86616}=0.0185512$

Hence, the value of $K_{eq}$ at 25°C is 0.0185512

<u>For C:</u>

We are given:

$[CoCl_4]^{2-}=0.234625M$

$[Co(H_2O)_6]^{2+}=0.765375M$

$[Cl^-]=1.06150M$

Putting values in equation 1, we get:

$K_{eq}=\frac{0.234625}{0.765375\times 1.06150}=0.2887886$

Hence, the value of $K_{eq}$ at 65°C is 0.2887886

<u>For D:</u>

For Endothermic reactions, $\Delta H>0$ , which is positive

For Exothermic reactions, $\Delta H$ , which is negative

To calculate $\Delta H$ of the reaction, we use Van't Hoff's equation, which is:

$\ln(\frac{K_{65^oC}}{K_{25^oC}})=\frac{\Delta H}{R}[\frac{1}{T_1}-\frac{1}{T_2}]$

where,

$K_{65^oC}$ = equilibrium constant at 65°C = 0.2887886

$K_{25^oC}$ = equilibrium constant at 25°C = 0.0185512

$\Delta H$ = Enthalpy change of the reaction = ?

R = Gas constant = 8.314 J/mol K

$T_1$ = initial temperature = $25^oC=[25+2730]K=298K$

$T_2$ = final temperature = $65^oC=[65+2730]K=338K$

Putting values in above equation, we get:

$\ln(\frac{0.2887886}{0.0185512})=\frac{\Delta H}{8.314J/mol.K}[\frac{1}{298}-\frac{1}{338}]\\\\\Delta H=57471.26J/mol$

As, the calculated value of $\Delta H>0$ . Thus, the reaction is endothermic in nature.

4 0

3 years ago

What Element is among the five most abundant element in the sun earth ocean atmosphere and organisms?

larisa86 [58]

Answer:

i would have to say oxygen .

Explanation:

6 0

3 years ago

What is the sum of all of the digits in the iupac name for the compound shown below?

Allisa [31]

I can’t answer the question sorry. I don’t know what the equation is

4 0

3 years ago