There are many important laws and theories in science. Which of the following is a law of science?

Match each situation below to a letter on the illustration.

Mnenie [13.5K]

Answer:a

Explanation:

4 0

2 years ago

Why are the electrons in a nitrogen-phosphorus covalent bond not shared equally? which atom do the electrons spend more time aro

a_sh-v [17]

Electrons in a nitrogen-phosphorus covalent bond are not shared equally because nitrogen and phosphorus do not have the same electronegativity. The atoms spend more time around the most electronegative atom nitrogen.

6 0

2 years ago

What are characteristics of absorption spectra? Check all that apply.

Amanda [17]

The absorption spectrum is the result of absorption of light radiation by a material (solid or liquid) as a function of wavelength or frequency. The figure is shown below:

7 0

2 years ago

Which balanced redox reaction is occurring in the voltaic cell represented by the notation of A l ( s ) | A l 3 ( a q ) | | P b

frez [133]

The question is missing. Here is the complete question.

Which balanced redox reaction is ocurring in the voltaic cell represented by the notation of $Al_{(s)}|Al^{3+}_{(aq)}||Pb^{2+}_{(aq)}|Pb_{(s)}$ ?

(a) $Al_{(s)}+Pb^{2+}_{(aq)} ->Al^{3+}_{(aq)}+Pb_{(s)}$

(b) $2Al^{3+}_{(aq)}+3Pb_{(s)} -> 2Al_{(s)}+3Pb^{2+}_{(aq)}$

(c) $Al^{3+}_{(aq)}+Pb_{(s)} ->Al_{(s)}+Pb^{2+}_{(aq)}$

(d) $2Al_{(s)}+3Pb^{2+}_{(aq)} -> 2Al^{3+}_{(aq)}+3Pb_{(s)}$

Answer: (d) $2Al_{(s)}+3Pb^{2+}_{(aq)} -> 2Al^{3+}_{(aq)}+3Pb_{(s)}$

Explanation: Redox Reaction is an oxidation-reduction reaction that happens in the reagents. In this type of reaction, reagent changes its oxidation state: when it loses an electron, oxidation state increases, so it is oxidized; when receives an electron, oxidation state decreases, then it is reduced.

Redox reactions can be represented in shorthand form called cell notation, formed by: left side of the salt bridge (||), which is always the anode, i.e., its half-equation is as an oxidation and right side, which is always the cathode, i.e., its half-equation is always a reduction.

For the cell notation: $Al_{(s)}|Al^{3+}_{(aq)}||Pb^{2+}_{(aq)}|Pb_{(s)}$

Aluminum's half-equation is oxidation:

$Al_{(s)} -> Al^{3+}_{(aq)}+3e^{-}$

For Lead, half-equation is reduction:

$Pb^{2+}_{(aq)}+2e^{-} -> Pb_{(s)}$

Multiply first half-equation for 2 and second half-equation by 3:

$2Al_{(s)} -> 2Al^{3+}_{(aq)}+6e^{-}$

$3Pb^{2+}_{(aq)}+6e^{-} -> 3Pb_{(s)}$

Adding them:

$2Al_{(s)}+3Pb^{2+}_{(aq)} -> 2Al^{3+}_{(aq)}+3Pb_{(s)}$

The balanced redox reaction with cell notation $Al_{(s)}|Al^{3+}_{(aq)}||Pb^{2+}_{(aq)}|Pb_{(s)}$ is

$2Al_{(s)}+3Pb^{2+}_{(aq)} -> 2Al^{3+}_{(aq)}+3Pb_{(s)}$

6 0

2 years ago

Explain how your experimental data for Rf values are, or are not, consistent with your predictions of enantiomeric and diastereo

hichkok12 [17]

Answer:

Answer is explained below.

Explanation:

As (+) menthol and (-) menthol are enantiomers whose physical properties are same except optical activity so we can expect they have similar Rf values.

Whereas diastereomers have different physical properties and different Rf values.

For example when the (+) menthol , (-) menthol, isomenthol and neomenthol undergo TLC (thin layer chromatography) the

Rf values of.(+menthol) = .447

Rf (+isomenthol) = .395

Rf (+neomenthol)= .487

Rf (-menthol) = .434

The above data shows that (+) menthol and (-) menthol have almost same Rf values and vary a little i.e 0.447 and 0.437. So we can conclude them as enantiomers

Whereas (+) menthol or (+) neomenthol or (+) isomenthol i.e 0.447 , 0.395 and 0.487 have different Rf values. We can conclude them as diasteromers.

(+) menthol and (-) menthol - enantiomers

(+) menthol and (+) neomenthol- diastereomers

(-) menthol and (+) isomenthol - diastereomers

3 0

2 years ago

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