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3 years ago

Liquid acetone is ______________.

Chemistry

1 answer:

MaRussiya [10]3 years ago

5 0

A is the answer maybe

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What must be the molarity of an aqueous solution of trimethylamine, (ch3)3n, if it has a ph = 11.20? (ch3)3n+h2o⇌(ch3)3nh++oh−kb

Stolb23 [73]

0.040 mol / dm³. (2 sig. fig.)

<h3>Explanation</h3>

$(\text{CH}_3)_3\text{N}$ in this question acts as a weak base. As seen in the equation in the question, $(\text{CH}_3)_3\text{N}$ produces $\text{OH}^{-}$ rather than $\text{H}^{+}$ when it dissolves in water. The concentration of $\text{OH}^{-}$ will likely be more useful than that of $\text{H}^{+}$ for the calculations here.

Finding the value of $[\text{OH}^{-}]$ from pH:

Assume that $\text{pK}_w = 14$ ,

$\begin{array}{ll}\text{pOH} = \text{pK}_w - \text{pH} \\ \phantom{\text{pOH}} = 14 - 11.20 &\text{True only under room temperature where }\text{pK}_w = 14 \\\phantom{\text{pOH}}= 2.80\end{array}$ .

$[\text{OH}^{-}] =10^{-\text{pOH}} =10^{-2.80} = 1.59\;\text{mol}\cdot\text{dm}^{-3}$ .

Solve for $[(\text{CH}_3)_3\text{N}]_\text{initial}$ :

$\dfrac{[\text{OH}^{-}]_\text{equilibrium}\cdot[(\text{CH}_3)_3\text{NH}^{+}]_\text{equilibrium}}{[(\text{CH}_3)_3\text{N}]_\text{equilibrium}} = \text{K}_b = 1.58\times 10^{-3}$

Note that water isn't part of this expression.

The value of Kb is quite small. The change in $(\text{CH}_3)_3\text{N}$ is nearly negligible once it dissolves. In other words,

$[(\text{CH}_3)_3\text{N}]_\text{initial} = [(\text{CH}_3)_3\text{N}]_\text{final}$ .

Also, for each mole of $\text{OH}^{-}$ produced, one mole of $(\text{CH}_3)_3\text{NH}^{+}$ was also produced. The solution started with a small amount of either species. As a result,

$[(\text{CH}_3)_3\text{NH}^{+}] = [\text{OH}^{-}] = 10^{-2.80} = 1.58\times 10^{-3}\;\text{mol}\cdot\text{dm}^{-3}$ .

$\dfrac{[\text{OH}^{-}]_\text{equilibrium}\cdot[(\text{CH}_3)_3\text{NH}^{+}]_\text{equilibrium}}{[(\text{CH}_3)_3\text{N}]_\textbf{initial}} = \text{K}_b = 1.58\times 10^{-3}$ ,

$[(\text{CH}_3)_3\text{N}]_\textbf{initial} =\dfrac{[\text{OH}^{-}]_\text{equilibrium}\cdot[(\text{CH}_3)_3\text{NH}^{+}]_\text{equilibrium}}{\text{K}_b}$ ,

$[(\text{CH}_3)_3\text{N}]_\text{initial} =\dfrac{(1.58\times10^{-3})^{2}}{6.3\times10^{-5}} = 0.040\;\text{mol}\cdot\text{dm}^{-3}$ .

8 0

3 years ago

Based on the six given solvents, which of the following answers lists ALL of the solvents that are NOT suitable for liquid-liqui

Zina [86]

Answer:

I don't know the answer sorry

6 0

2 years ago

A + B ->C<br><br><br>Which situation best describes the effect of a limiting reactant?

anygoal [31]

Answer:

The Limiting Reactant is the reactant that when consumed the reaction stops.

Explanation:

7 0

3 years ago

How do I find the number of electrons in an Isotope? For example, I know that in the image attached the isotope has 45 protons a

vova2212 [387]

Answer:

The answer to your question is: 45 electrons

Explanation:

Isotopes are molecules that have the same number of protons but the number of neutrons is different.

Also, in a neutral atom, the number of protons and electrons is the same.

In the example given, we can see that the atom is neutral so, the number of protons = 45 and the number of electrons = 45.

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2 years ago

Iron reacts with oxygen to produce iron oxide rust this reaction is representative in an equation as to FE plus XO22FE203 identi

igomit [66]

The balanced equation :

4Fe + 3O₂⇒ 2Fe₂O₃

<h3>Further explanation</h3>

Given

Rust reaction

Required

Balanced equation

Solution

Reaction

Fe + O₂⇒ 2Fe₂O₃

For a simple equation where one of the reaction coefficients is known, we can immediately add the corresponding coefficient using the principle that the number of atoms of <em>the components in the reactants and products is the same. </em>

In the above reaction :

Fe, left=1, right = 4, so coefficient in the left=4

O, left=2, right = 6, so coefficient in the left=3

3 0

2 years ago