Download the App!

Get 24/7 study help with the Numerade app for iOS and Android! Enter your email for an invite.

Get the answer to your homework problem.

Try Numerade free for 7 days

Like

Report

The $\mathrm{pH}$ of a $0.30 \mathrm{M}$ solution of a weak base is 10.66. What is the $K_{\mathrm{b}}$ of the base?

$$0,6963 \cdot 10^{-6} \text {mol} \cdot\text{due }^{-3}$$

Chemistry 102

Chapter 15

Acids and Bases

Liquids

Rice University

Drexel University

Lectures

03:07

A liquid is a nearly incompressible fluid that conforms to the shape of its container but retains a (nearly) constant volume independent of pressure. As such, a liquid is one of the four fundamental states of matter (the others being solid, gas and plasma). A liquid is made up of tiny vibrating particles of matter, such as atoms, held together by intermolecular bonds. Water is, by far, the most common liquid on Earth. Like a gas, a liquid is able to flow and take the shape of a container. Most liquids resist compression, although others can be compressed. Unlike a gas, a liquid does not disperse to fill every space of a container, and maintains a fairly constant density. A distinctive property of the liquid state is surface tension, leading to wetting phenomena.

04:38

A liquid is a state of matter in which a substance changes its shape easily and takes the form of its container, and in which the substance retains a constant volume independent of pressure. As a result of this, a liquid does not maintain a definite shape, and its volume is variable. The characteristic properties of a liquid are surface tension, viscosity, and capillarity. The liquid state has a definite volume, but it also has a definite surface. The volume is uniform throughout the whole of the liquid. Solids have a fixed shape and a definite volume, but they do not have a definite surface. The volume of a solid does not vary, but the volume of a liquid may vary.

01:19

The $\mathrm{pH}$ of a $0.…

02:42

03:56

A $0.12 M$ solution of a w…

01:18

Determine the $K_{\mathrm{…

01:06

If a weak base is $0.030 \…

04:55

Calculate the pH of a $0.2…

03:38

A 0.135 M solution of a we…

All right, so in this question, were given a 0.3 moles per liter off some unknown base. We know that the pH that results from it is 10.66 And what we gotta find is the KB value are the ionization constants. Okay, So an important thing when finding the ionization constant is the, um ah hydroxide concentration. So let's use this pH to find the hydroxide concentration. So the first thing I remember is ph plus p o h equals 14 which means the P L O. H would be 14 minus 10.66 leaving you with a value of 3.34 So let's take that and find the hydroxide concentration by two in the anti log of negative 3.34 which is 10 to the negative 3.34 which will give you a value of 4.6 times. Tend to the negative four. All right, now, that should help us to ah, get this value to, um, the Sion ization constant. Now let's make sure we know what we need. We need the H B plus that's like the contra gate acid concentration times. The hydroxide concentration, which we just found, um, divided by the base concentration. Not exactly the 0.3 we started with, but whatever's left at equilibrium, so we know the hydroxide concentration is 4.6% of the negative, for we just found that that's also going to be the same as the congregate acid concentration or the cat ion. Now, the base concentration that'll be. We started a 0.3 and we lose that value. They got ionized the 4.6. I'm sending the negative four. Now, if you subtract that, you'll see, um, you can try it. You'll get 0.29954 See how close it is, 0.3. It's hardly change it all. So to simplify the problem, we could just leave it. A 0.3 causes so close and you'll see that happens a lot. Um, now we've got all the numbers we need to plug in. So since both of the top values and 4.6% of the negative four will just square that and then put that 0.3 on the bottom so squared you'll have a 2.12 times in the negative seven on the top. Divide that by 0.3 Um, and then that's it. Ah, plug it in and you'll get your final KB value remembered around the two significant figures. You'll have 7.1 times 10 to the negative seven, and that's it.

View More Answers From This Book

Find Another Textbook

Numerade Educator

02:27

Consider the reaction $\mathrm{A} \longrightarrow \mathrm{B}+\mathrm{C}$ at …

02:11

In the metabolism of glucose, the first step is the conversion of glucose to…

02:04

A $0.050 M$ hydrofluoric acid (HF) solution is 11 percent ionized at $25^{\c…

08:01

Balance the following redox equations by the ionelectron method:(a) $\ma…

01:32

Are enzyme-catalyzed reactions examples of homogeneous or heterogeneous cata…

02:22

Use the data in Appendix 3 to calculate the equilibrium constant for the rea…

00:58

Oxygen $\left(\mathrm{O}_{2}\right)$ and carbon dioxide $\left(\mathrm{CO}_{…

03:06

Consider the following mechanism for the enzymecatalyzed reaction:$$\mat…

14:26

Write three resonance structures for (a) the cyanate ion $\left(\mathrm{NCO}…

11:07

Because of its detrimental effect on the environment, the lead compound desc…