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Gwar [14]
3 years ago
10

In the spectrophotometric analysis of benzene, the calibration curve has a slope of 195 AU/M and an intercept of 0.079 AU. If an

unknown has an absorbance of 0.517 AU, what is the concentration of benzene in the sample?
a. 2.09 x10^-4 M
b. 2.25 x 10^-3 M
c. 2.65 x 10^-3 M
d. 0.438 M
Chemistry
1 answer:
zloy xaker [14]3 years ago
5 0

Answer:

b. 2.25 x 10^-3 M

Explanation:

Please remember that according to Beer´s, law the absorbance is given by

A = Acl where A = absorbance, A is the molar absorptivity, c is concentration (M) and l is the path length of the cubette of used.

Now it follows from this equation that the absorbance is linearly related to concentration and what we are being told is that experimentally the linear equation obtained during calibration was:

A = 195 c + 0.079

We have all the information required to solve this question to solve for c:

0.517 = 195 c + 0.079 ⇒ c = (0.517 - 0.079) AU/ 195 AU/M = 2.25 x 10⁻³ M

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Answer:

carbon dioxide

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On the following chemical equation, label the acid, the base, the
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Answer:

HX (aq)    +     H₂O (l)  ⇄      H₃O⁺ (aq)    +     X⁻ (aq)  

Acid                  Base          Conj. acid          Conj. base  

Explanation:

The equation is:

HX (aq) + H₂O (l)  ⇄   H₃O⁺ (aq) + X⁻ (aq)

This is the typical equilibrium for a weak acid. It would complete if we notice the Ka.

HX (aq) + H₂O (l)  ⇄   H₃O⁺ (aq) + X⁻ (aq)    Ka

1 mol of hypothetic HX acid react to 1 mol of water in order to release a proton and make hydronium and generate the X⁻ anion.

HX will be the acid, in this case a weak one and water will be the base. Water is able to accept a proton to make itslef hydronium

Hydronium is the conjugate acid.

The X⁻ will be the conjugate strong base.

This ion can generate the acid form again, that's why it is strong, because it can make hydrolisis.

X⁻ (aq)  +  H₂O (l)  ⇄  HX (aq) +  OH⁻(aq)     Kb

In this case, the anion will be the conjugate base which it takes a proton from water (acid form) to make a conjugate acid, the HX and a conjugate base, OH⁻

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3 years ago
How many moles of H atoms are in 15.2 grams of pure ice?
nikitadnepr [17]

The number of moles of H atoms in 15.2 grams of pure ice is 0.850 moles

The number of moles of O atoms in 15.2 grams of pure ice is 13.50 moles

<h3>What is an atom?</h3>

An atom is a smallest indivisible particle of a chemical element that is capable of independent existence.

  • Pure ice contains the H2O molecules and the molar mass of H2O is 18.02 g/mol

Using the relation:

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The number of moles of H2O = 15.2 grams/18.02 g/mol

number of moles of H2O = 0.8435 moles

If the atomic mass of H and O are as follow:

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  • the atomic mass of O atom is = 15.999 g/mol

Then:

the number of H atoms in 15.2 grams of pure ice = mass of H atom × molar mass of H2O.

the number of H atoms = 0.8435 mol × 1.00784 g/mol

the number of H atoms = 0.850 moles

the number of O atoms in 15.2 grams of pure ice = 0.8435 mol × 15.999 g/mol

the number of O atoms = 13.50 moles

Learn more about atoms here:

brainly.com/question/25832904

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