In order to qualify as matter, the object must

Which of the following compounds has the lowest boiling point?

sergejj [24]

Answer : The correct answer is option A : Diethyl ether

Explanation :

The boiling point of a compound depends on the intermolecular forces (IMF) of attractions present among its molecules.

Stronger the IMF, more difficult it is to separate the molecules. And hence the compound shows higher boiling point.

The most common types of IMF are

a) Hydrogen bonding : Hydrogen bonding occurs when a compound has hydrogen atom directly attached to strongly electro-negative atoms like O, N and F

Hydrogen bondings are the strongest IMF. Therefore compounds that have hydrogen bondings show higher boiling point.

In the given examples, 2-butanol and 4-octanol both have -OH group where H is directly attached to highly electro-negative O atom. As a result hydrogen bonding is present in these compounds.

Therefore they show higher boiling point.

b) Dipole interactions : These are seen in case of polar compounds.

c) London dispersion forces : These are present in all the compounds but they are predominant in case of non polar compounds.

Both diethyl ether and diphenyl ether predominantly show London dispersion forces. Since these forces are weaker as compared to other IMF, the molecules having london dispersion tend to have lower boiling points.

But the magnitude of dispersion forces increases as the molecular weight of the compound increases.

Therefore diphenyl ether which has a molecular weight of 170 g/mol has much stronger london dispersion forces as compared to diethyl ether which has a molecular weight of 74 g/mol

From above discussion, we can conclude that diethyl ether has the weakest intermolecular forces of attraction. Hence it has the lowest boiling point.

6 0

4 years ago

Calculate the percent dissociation of trimethylacetic acid(C6H5CO2H) in a aqueous solution of the stuff.

Sophie [7]

Answer:

1.112%.

Explanation:

Step one : write out the correct acid dissociation reaction. This is done below:

C6H5CO2H <=====> C6H5CO2^- + H^+.

At equilibrium, the concentration of C6H5CO2H = 0.5 M - x and the concentration of C6H5CO2^- = x and the concentration of H^+ = x.

The ka for C6H5CO2H = 6.3 × 10^-5.

Step two: find the value for the concentration of C6H5CO2^- and H^+. This can be done by using the equilibrium dissociation Constant formula below;

Ka = [C6H5CO2^- ] [H^+] / C6H5CO2H.

ka = [x] [x] / [0.5 - x].

6.3 × 10^-5 = (x)^2 / [0.5 - x].

x^2 = 3.15 ×10^-5 - 6.3 × 10^-5 x.

x^-2 + 6.3 × 10^-5 x - 3.15 × 10^-5.

Solving for x we have x= 0.0055632289702004 = 0.00556.

Therefore, at equilibrium the concentration of H^+ = 0.00556 M and the concentration of C6H5CO2H= O.5 - 0.00556 = 0.494 M.

Step three: Calculate the equilibrium pH. This stage can be ignored for this question since we are not asked to calculate for the pH.

The formular for pH = - log [H^+].

pH= - log [0.00556].

pH= 2.255.

Step four: find the percentage dissociation.

Percentage dissociation = ( [H^+] at equilibrium/ [ C6H5CO2H] at Initial concentration ) × 100%.

Percentage dissociation=( 0.00556/ 0.5 ) × 100.

=Percentage dissociation= 1.112%.

3 0

4 years ago

Balance the equation for this reaction in an acidic solution MnO-4 to NO-3+Mn+2

marin [14]

Answer

MnO₄ + 2H⁺ +3NO₂⁻ →3NO₃⁻ + Mn²⁺ +H₂O

Explanation

This is a redox reaction (oxidation-reduction reaction) which involves the transfer of electrons between two species. i.e

Mn + 6e⁻→Mn²⁺ (reduction)

3N³⁺- 6e⁻→3Mn⁵⁺(oxidation)

4 0

4 years ago

Read 2 more answers

Calculate the mass in grams of carbon needed to produce 160 g of CO2 in burning: C + O2 --> CO2

Vladimir [108]

160gof CO2×1molof CO2\44g of CO2×1mole of C\1mol of CO2×12g of C\1mole of C=
43.63g of C

5 0

3 years ago

According to scientific evidence, earth’s earliest atmosphere lacked oxygen. Over time, oxygen was added to the atmosphere.

Marianna [84]

B.
The cynobacteria were already there without the oxygen, so that rules out A, and a lot of prokaryotes were anaerobic, so that rules out C. Finally, Photosynthesis does not require oxygen. Instead, Oxygen is a waste product of it. Therefore, it cannot be D. So, we are only left with B
Hoped this helped :D

4 0

3 years ago