WHICH RIBBON WOULD BE CONSIDERED THE SENIOR RIBBON AND WOULD BE PLACED TO THE LEFT NEAR YOUR HEART?

Calculate the concentrations of all species present in a 0.26 M solution of ethylammonium chloride (C2H5NH3Cl).

Alina [70]

Answer:

0.00000223

Explanation:

pKa for C2H5NH3+ = 10.7

pKw = 14.0

pKa + pKb = pKw

10.7 + pKb = 14.0

pKb = 14.0 - 10.7

pKb = 3.30

C2H5NH3Cl is a salt of ethylamine and HCl so it will dissolve in water to produce C2H5NH3^+ + Cl^-

The base hydrolysis reaction: C2H5NH3^+(aq) + H2O(l) <=> C2H5NH2(aq) + H3O^+(aq)

This reaction is described by Kb.

Kb = [C2H5NH2][H3O^+]/[C2H5NH3^+]

Let [C2H5NH2] = [H3O^+] = x,

so [C2H5NH3^+] = 0.26 - x

Kb = x^2/(0.26 - x) = 2.00 x 10^-11

Let's solve for x. In this equation, It is possible to solve without the use quadratic equation. So we can assume that 0.26 - x is approximately equal to 0.26. We won't know until we do the calculation.

We get: x^2 + 2.00 x 10^-11x - 4.99 x 10^-12 = 0

With the use of a quadratic calculator.

x = 2.23 x 10^-6 M = [C2H5NH2] = [H3O^+]

0.26 - x is just 0.26 M in this problem because 2.23 x 10^-6 M is insignificant.

[C2H5NH3^+] = 0.26 M = [Cl^-]

NOTE:

pH = -log [H3O^+] = -log(2.23 x 10^-6) = 5.65

Ka is the acid dissociation constant

Kb is the base dissociation constant

5 0

3 years ago

A bottle of coke is 250.0 mL. What is the volume in cubic centimeters?

hoa [83]

Answer:

The volume in cubic centimeters is 250

Explanation:

The rule of three or is a way of solving problems of proportionality between three known values and an unknown value, establishing a relationship of proportionality between all of them.

If the relationship between the magnitudes is direct, that is, when one magnitude increases, so does the other (or when one magnitude decreases, so does the other), the direct rule of three must be applied. To solve a direct rule of three, the following formula must be followed:

a ⇒ b

c ⇒ x

So:

$x=\frac{c*b}{a}$

The direct rule of three is the rule applied in this case where there is a change of units. To perform this conversion of units, you must first know that 1 mL = 1 cubic centimeters. So, if 1 cubic centimeters is 1 mL, how many cubic centimeters equals 250 mL?

$cubic centimeters=\frac{250 mL*1 cubic centimeters }{1 mL}$

cubic centimeters= 250

The volume in cubic centimeters is 250

3 0

3 years ago

5. An element whose highest occupied s sublevel and a nearby d sublevel contain electrons

Mumz [18]

Answer:

Transition Element

Explanation:

Transition elements are defined as those elements which can form at least one stable ion and has partially filled d-orbitals. They are also characterized by forming complex compounds and having different oxidation states for a single metal element.

Transition metals are present between the metals and the non metals in the periodic table occupying groups from 3 to 12. There general electronic configuration is as follow,

(n-1)d ¹⁻¹⁰ns ¹⁻²

The general configuration shows that for a given metal, the d sublevel will be in lower energy level as compared to corresponding s sublevel. For example,

Scandium is present in fourth period hence, its s sublevel is present in 4rth energy level so its d sublevel will be present in 3rd energy level respectively.

Hence, we can conclude that for transition metals the electron are present in highest occupied s sublevel and a nearby d sublevel .

5 0

4 years ago

Name 3 sources of carbohydrates for the production of an alcoholic drink

icang [17]

Answer:An alcoholic drink is a drink that contains ethanol, a type of alcohol produced by fermentation of grains, fruits, or other sources of sugar. The consumption of alcohol plays an important social role in many cultures. Most countries have laws regulating the production, sale, and consumption of alcoholic beverages.

Explanation: vodka the preferred alcoholic beverage of choice among alcoholics? #3 Doesn't make you feel bloated or full like beer does. It goes down quickly and smooth. #4 Gets you drunk just as fast as any other hard liquor can, and obviously much faster than beer or wine.

4 0

3 years ago

Silicon has a relatively large latent heat of vaporization of 12800 J/g. This indicates that silicon has:

beks73 [17]

I believe it means that it takes a lot of heat in joules to make silicon vaporize so it stays solid until a great deal of heat has been added. By comparison, water has a latent heat of about 2260 joules per gram so vaporizes much more readily than silicon.

3 0

3 years ago