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Lunna [17]
3 years ago
15

The concentration of Fe2 in a sample is determined by measuring the absorbance of its complex with ferroxine. The sample, measur

ed in a 1.00 cm cuvette, has an absorbance of 0.242 . The reagent blank in the same cuvette has an absorbance of 0.041. What would be the absorbance reading for each of these two solutions if measured in a 5.00 cm cuvette
Chemistry
1 answer:
sdas [7]3 years ago
8 0

Answer:

  • Absorbance of sample solution = 1.21
  • Absorbance of reagent blank = 0.205

Explanation:

In order to solve this problem we need to keep in mind the <em>Lambert-Beer law</em>, which states:

  • A = ε*b*C

Where ε is the molar absorption coefficient, b is the length of the cuvette, and C is the concentration.

By looking at the equation above we can see that if ε and C are constant; and b is 5 times higher (5.00 cm vs 1.00 cm) then the absorbance will be 5 times higher as well:

  • Absorbance of sample solution = 0.242 * 5 = 1.21
  • Absorbance of reagent blank = 0.041 * 5 = 0.205
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I need help pleaseee help please! &lt;3
kobusy [5.1K]

(a) The temperature goes up by 3⁰C.

(b) There is increase in temperature, so the reaction is exothermic.

(c) Examples of exothermic reaction include, rusting of Iron, burning of coal, reaction of strong acid and water.

(d) Examples of endothermic reaction include, melting solid salts and evaporating liquid water.

<h3>What is exothermic reaction?</h3>

Exothermic reaction is a type of chemical reaction in which energy is transferred to or from the surroundings.

Examples of exothermic reactions include the following;

  • Rusting of Iron
  • Burning of Coal
  • Reaction of Strong Acid and Water
  • Water and Calcium Chloride

<h3>What is endothermic reaction?</h3>

Endothermic reaction is a type of chemical reaction in which energy is absorbed from the surroundings.

Examples of endothermic reactions include the following;

  • Melting solid salts.
  • Evaporating liquid water, etc

<h3>Change in temperature</h3>

From the increase in temperature from 15⁰C to 23⁰C, we can conclude that the temperature goes up by 3⁰C.

20⁰C - 17⁰C = 23⁰ - 20⁰C = 3⁰C.

Since there is increase in temperature, the reaction is exothermic.

Learn more about exothermic reaction here: brainly.com/question/2924714

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4 0
1 year ago
Below are shown, for five metals, reduction reactions and standard electrode potential values. which of these metals is the leas
just olya [345]
Above question is incomplete. Complete question is attached below
........................................................................................................................
Solution:
Reduction potential of metal ions are provided below. Higher the value to reduction potential, greater is the tendency of metal to remain in reduced state.

In present case, reduction potential of Au is maximum, hence it is least prone to undergo oxidation. Hence, it is least reactive.

On other hand, reduction potential of Na is minimum, hence it is most prone to undergo oxidation. Hence, it is most reactive. 


7 0
4 years ago
You are presented with a white solid and told that due to careless labeling it is not clear if the substance is silver fluoride,
Lerok [7]
Because the solid is soluble in water, it cannot be calcium fluoride.
This leaves us with either silver fluoride or potassium bromide, as both are soluble in water.

Upon addition of sodium sulfate, a white precipitate forms, confirming that the substance was silver fluoride as the precipitate are of silver sulfate.
4 0
4 years ago
Reactions that absorb thermal energy are called blank reactions
Valentin [98]
Endothermic reactions
7 0
3 years ago
An uncharged atom of mercury has an atomic number of 80 and an atomic mass of 200. This atom has ________ protons, ________ neut
SCORPION-xisa [38]
<h3>Answer:</h3>

             This atom has 80 protons, 120 neutrons and 80 electrons.

<h3>Explanation:</h3>

Number of Protons:

                               As the number of protons present in the nucleus are equal to the atomic number therefore. As given, the atomic number is 80 therefore, Hg contains 80 protons respectively.

Number of Electrons:

                                 As given in statement, Hg is not carrying any type of charge. It means this atom is neutral in nature. Which means, it is carrying the same number of electrons as the number of protons in order to give a neutral atom. Therefore, it contains 80 electrons.

Number of Neutrons:

                                 Number of neutrons can be calculated using following formula,

                  No. of Neutrons  =  Atomic Mass - Number of Protons

As,

                                    Atomic Mass  =  200

So,

                                    No. of Neutrons  =  200 - 80

                                    No. of Neutrons  =  120

3 0
3 years ago
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