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3 years ago

Which is not true for a catalyst?

Chemistry

1 answer:

maria [59]3 years ago

3 0

Answer: (A) It appears as a reactant in the net chemical reaction

Explanation:

A catalyst is A substance that speed up the chemical reaction without its self being consumed in the reactants or the products.It does this by lowering the activation energy of the reaction by speeding up the rate of reaction.

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(1) How did Democritus characterize atoms?

bija089 [108]

1. Democritus characterized atoms as indestructible and indivisible.

3 0

3 years ago

13. How many electrons are transferred in the following reaction? (The reaction is unbalanced.) Fe(s) + I'(aq) 12(s) + Fe3+(aq)

Nat2105 [25]

Answer : The correct option is, (C) 6

Explanation :

Oxidation-reduction reaction : It is a reaction in which oxidation and reduction reaction occur simultaneously.

Oxidation reaction : It is the reaction in which a substance looses its electrons. In this oxidation state increases.

Reduction reaction : It is the reaction in which a substance gains electrons. In this oxidation state decreases.

The given unbalanced chemical reaction is,

$Fe(s)+I^-(aq)\rightarrow I_2(s)+Fe^{3+}(aq)$

Half reactions of oxidation and reduction are :

Oxidation : $Fe(s)\rightarrow Fe^{3+}+3e^-$ ......(1)

Reduction : $2I^-(aq)+2e^-\rightarrow I_2$ .......(2)

In order to balance the electrons, we multiply equation 1 by 2 and equation 2 by 3, we get:

Oxidation : $2Fe(s)\rightarrow 2Fe^{3+}+6e^-$ ......(1)

Reduction : $6I^-(aq)+6e^-\rightarrow 3I_2$ .......(2)

The overall balanced chemical reaction will be:

$2Fe(s)+6I^-(aq)\rightarrow 3I_2(s)+2Fe^{3+}(aq)$

From this reaction we conclude that the electrons are getting transferred from iron to iodine and the number of electrons transferred are 6 electrons.

Hence, the correct option is, (C) 6

5 0

3 years ago

(ii) Electrons are supplied to the external circuit. How and where is this done?<br> [2]

pentagon [3]

Answer:

The electrons are supplied by the species getting oxidized. They move from anode to the cathode in the external circuit. The external battery supplies the electrons. They enter through the cathode and come out through the anode

7 0

3 years ago

Predict the products of the thermal decomposition of strontium nitrate and show the reaction as a word equation.

Schach [20]

yeag

Explanation:

2SrO + 4NO2 + O. The thermal decomposition of strontium nitrate to produce strontium oxide, nitrogen dioxide and oxygen. This reaction takes place at a temperature of over 570°C

6 0

3 years ago

Which one of the following best represents the predicted approximate chemical shift and coupling for the hydrogen(s) indicated w

melomori [17]

Answer:

The answer is quartet 2.40 ppm.

Note: Kindly find an attached image below for the part of the solution to this question

Sources: The image was researched from Course hero platform

Explanation:

Solution

Multiplicity or (n+1) rule:

It helps in determination of multiplicity of an individual proton or individual types of proton which are available in the molecule.

Multiplicity =(n+1)

Thus

The non equivalent protons which are attached from adjacent atom is denoted by n.

Now because there are three non-equivalent protons are present at adjacent carbon of methylene group, hence the multiplicity of methylene hydrogen is given as follows:

The multiplicity will be the same for the two hydrogen's. thus we compute multiplicity only for one hydrogen atom stated below:

Non- equivalent = 3

Multiplicity = (3 +1)

= 4

= Quartet for 2H

A quartet for 2H indicates that the hydrogen atoms attached from the carbon, which is attached one side from a methyl group and the other side form an atom that have no any hydrogens.

Now due +I effect of carbonyl group, chemical shift value is high for these two hydrogens which is exactly at 2.40 ppm or 2.40 Quartet.

5 0

4 years ago