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2 years ago

In general, the presence of atoms of what element(s) makes a molecule polar

1 answer:

3 0

Polarity of a molecule doesn't depend only on the presence of certain atom(s). It also depends on symmetry. For example, take the alkanes family $C_{n}H_{2n+2}$ . These molecules are generally nonpolar, because there is no net dipole moment. Now, dipole moment arises due to difference in the electronegativity of carbon and the other element. In organic chemistry, generally these atoms are Oxygen, Halogens, Nitrogen. Because of their high electronegativity, they cause a net dipole moment resulting in polarity.

 $H_3C-CH_3$ is symmetrical and hence non-polar.

$H_3C-O-CH_3$ is asymmetrical and polar. It's structure is bent because of oxygen lone pairs.

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How many moles of hydrogen gas are produced when 0.066 mole of sodium is completely reacted?

SVEN [57.7K]

Base on my research the complete reaction of hydrogen and sodium are form by this equation 2Na + 2H2O = 2NaOH +H2 If we base from this equation it shows you already the ratio of the moles of the product and reactants taking part in the reaction

1 mole of Na r/w 1 mole of water to produce .5 mole of Hydrogen

Therefore, .066 mole of Na produces .033 moles of H2

6 0

2 years ago

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Consider the elements in the periodic table. The stair-step line between the pink squares and the yellow squares separates the _

Maru [420]

I believe the correct answer from the choices listed above is option B. The stair-step line between the pink squares and the yellow squares separates the metals from the nonmetals. Hope this answers the question. Have a nice day.

4 0

2 years ago

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In Philip’s French class, the students are learning how to pronounce closed vowels and open vowels. The students are most likely

Sladkaya [172]

Answer:

It sounds like they are studying French phonemes

Explanations:

I just learned this.

7 0

2 years ago

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Consider a general reaction A ( aq ) enzyme ⇌ B ( aq ) A(aq)⇌enzymeB(aq) The Δ G ° ′ ΔG°′ of the reaction is − 5.980 kJ ⋅ mol −

Grace [21]

Answer : The value of $K_{eq}$ is, 11.2

The value of $\Delta G_{rxn}$ is -9.04 kJ/mol

Explanation :

The relation between the equilibrium constant and standard Gibbs free energy is:

$\Delta G^o=-RT\times \ln K_{eq}$

where,

$\Delta G^o$ = standard Gibbs free energy = -5.980 kJ/mol = -5980 J/mol

R = gas constant = 8.314 J/K.mol

T = temperature = $25^oC=273+25=298K$

$K_{eq}$ = equilibrium constant = ?

Now put all the given values in the above formula, we get:

$\Delta G^o=-RT\times \ln K_{eq}$

$-5980J/mol=-(8.314J/K.mol)\times (298K)\times \ln K_{eq}$

$K_{eq}=11.2$

Thus, the value of $K_{eq}$ is, 11.2

Now we have to calculate the $\Delta G_{rxn}$ .

The formula used for $\Delta G_{rxn}$ is:

The given reaction is:

$A(aq)\rightleftharpoons B(aq)$

$\Delta G_{rxn}=\Delta G^o+RT\ln Q$

$\Delta G_{rxn}=\Delta G^o+RT\ln \frac{[B]}{[A]}$ ............(1)

where,

$\Delta G_{rxn}$ = Gibbs free energy for the reaction = ?

$\Delta G_^o$ = standard Gibbs free energy = -30.5 kJ/mol

R = gas constant = $8.314\times 10^{-3}kJ/mole.K$

T = temperature = $37.0^oC=273+37.0=310K$

Q = reaction quotient

[A] = concentration of A = 1.8 M

[B] = concentration of B = 0.55 M

Now put all the given values in the above formula 1, we get:

$\Delta G_{rxn}=(-5980J/mol)+[(8.314J/mole.K)\times (310K)\times \ln (\frac{0.55}{1.8})$

$\Delta G_{rxn}=-9035.75J/mol=-9.04kJ/mol$

Therefore, the value of $\Delta G_{rxn}$ is -9.04 kJ/mol

3 0

2 years ago

The pK1, pK2, and pKR of the amino acid lysine are 2.2, 9.1, and 10.5, respectively. The pK1, pK2, and pKR of the amino acid arg

almond37 [142]

Answer:

pH 9,8 is likely to work best for this separation

Explanation:

Ion exchange chromatography is a chemical process where molecules are separated by affinity to an ion exchange resin. To separate different aminoacids you must use the isoelectric point (That is the pH where the aminoacid will be in its neutral form).

For lysine, PI is:

$pH = \frac{1}{2} (9,1+10,5) =$ 9,8

For arginine:

$pH = \frac{1}{2} (9,0+12,5) =$ 10,75

At pH = 9,8 lysine will be in its neutral form and will not be retain in the column but arginine will be in +1 charge being retained by the ion exchange resin.

Thus, pH 9,8 is likely to work best for this separation

I hope it helps!

5 0

2 years ago