If 21.00 mL of a 0.68 M solution of C6H5NH2 required 6.60 mL of the strong acid to completely neutralize the solution, what was the final pH at the equivalence point
Answer:
pH = 2.46
Explanation:
Hello there!
In this case, since this neutralization reaction may be assumed to occur in a 1:1 mole ratio between the base and the strong acid, it is possible to write the following moles and volume-concentrations relationship for the equivalence point:
[tex]n_{acid}=n_{base}=n_{salt}[/tex]
Whereas the moles of the salt are computed as shown below:
[tex]n_{salt}=0.021L*0.68mol/L=0.01428mol[/tex]
So we can divide those moles by the total volume (0.021L+0.0066L=0.0276L) to obtain the concentration of the final salt:
[tex][salt]=0.01428mol/0.0276L=0.517M[/tex]
Now, we need to keep in mind that this is an acidic salt since the base is weak and the acid strong, so the determinant ionization is:
[tex]C_6H_5NH_3^++H_2O\rightleftharpoons C_6H_5NH_2+H_3O^+[/tex]
Whose equilibrium expression is:
[tex]Ka=\frac{[C_6H_5NH_2][H_3O^+]}{C_6H_5NH_3^+}[/tex]
Now, since the Kb of C6H5NH2 is 4.3 x 10^-10, its Ka is 2.326x10^-5 (Kw/Kb), we can also write:
[tex]2.326x10^{-5}=\frac{x^2}{0.517M}[/tex]
Whereas x is:
[tex]x=\sqrt{0.517*2.326x10^{-5}}\\\\x=3.47x10^-3[/tex]
Which also equals the concentration of hydrogen ions; therefore, the pH at the equivalence point is:
[tex]pH=-log(3.47x10^{-3})\\\\pH=2.46[/tex]
Regards!
In which atmospheric layer is the ozone layer? O stratosphere o thermosphere O mesosphere troposphere
Answer:
The stratosphere
Explanation:
How many grams of phosphorous is in the human skeleton if its average
weight is 11 kg and contains 58% of calcium phosphate (Ca3(PO4)2)?
A key process common to all organisms is the ability to reproduce. Where do all cells come from?
A. from ova
B. from atoms
C. from gametes
D. from pre-existing cells
Answer:
It’s d
Explanation:
It’s d 100%
how many grams are there in 3400 moles of tetranitrogen dicarbide?
Explanation:
molar mass of tetranitrogen dicarbide S4N4= 4×32+4×14
128+56
184 g/mol
no.of moles =given mass/ molar mass
3400= given mass / 184
3400×184 =given mass.
625600 g
Rubbing alcohol is 70.% (v/v) isopropyl alcohol by volume. How many mL of isopropyl alcohol are in a 1 pint (473 mL) container? Rubbing alcohol is 70.% (v/v) isopropyl alcohol by volume. How many mL of isopropyl alcohol are in a 1 pint (473 mL) container? 330 mL 470 mL 70. mL 680 mL 0.15 mL
Answer:
helped
The number of ml of isopropyl alcohol that are 1 pint (473 Ml) is 331.1 Ml
calculation
assume that the 1 pint is in a container
This implies that the 1 pint (473 ml) is in 100 % M/V
what about 70 %(M/V)
that is 473 Ml = 100 %
? = 70 %
by cross multiplication
= 473 x70/100 = 331.1 Ml
Explanation:
Which is not true of the cell theory?
which is NOT true about the cell theory?
A:all living organisms are composed of cells
B:all cells have a nucleus, which acts like the brain of the cell
C:all cells come preexisting living cells
D:the cell is the most basic part of a living organism
2) A common "rule of thumb" -- for many reactions around room temperature is that the
rate will double for each ten degree increase in temperature. Does the reaction you hav
studied seem to obey this rule.
The question is incomplete. The complete question is :
A common "rule of thumb" for many reactions around room temperature is that the rate will double for each ten degree increase in temperature. Does the reaction you have studied seem to obey this rule? (Hint: Use your activation energy to calculate the ratio of rate constants at 300 and 310 Kelvin.)
Solutions :
If we consider the activation energy to be constant for the increase in 10 K temperature. (i.e. 300 K → 310 K), then the rate of the reaction will increase. This happens because of the change in the rate constant that leads to the change in overall rate of reaction.
Let's take :
[tex]$T_1=300 \ K$[/tex]
[tex]$T_2=310 \ K$[/tex]
The rate constant = [tex]$K_1 \text{ and } K_2$[/tex] respectively.
The activation energy and the Arhenius factor is same.
So by the arhenius equation,
[tex]$K_1 = Ae^{-\frac{E_a}{RT_1}}$[/tex] and [tex]$K_2 = Ae^{-\frac{E_a}{RT_2}}$[/tex]
[tex]$\Rightarrow \frac{K_1}{K_2}= \frac{e^{-\frac{E_a}{RT_1}}}{e^{-\frac{E_a}{RT_2}}} $[/tex]
[tex]$\Rightarrow \frac{K_1}{K_2}= e^{-\frac{E_a}{R}\left(\frac{1}{T_1}-\frac{1}{T_2}\right)}$[/tex]
[tex]$\Rightarrow \ln \frac{K_1}{K_2}= - \frac{E_a}{R} \left(\frac{1}{T_1} -\frac{1}{T_2} \right)$[/tex]
[tex]$\Rightarrow \ln \frac{K_2}{K_1}= \frac{E_a}{R} \left(\frac{1}{T_1} -\frac{1}{T_2} \right)$[/tex]
Given, [tex]$E_a = 0.269$[/tex] J/mol
R = 8.314 J/mol/K
[tex]$\Rightarrow \ln \frac{K_2}{K_1}= \frac{0.269}{8.314} \left(\frac{1}{300} -\frac{1}{310} \right)$[/tex]
[tex]$\Rightarrow \ln \frac{K_2}{K_1}= \frac{0.269}{8.314} \times \frac{10}{300 \times 310}$[/tex]
[tex]$\Rightarrow \ln \frac{K_2}{K_1}= 3.479 \times 10^{-6}$[/tex]
[tex]$\Rightarrow \frac{K_2}{K_1}= e^{3.479 \times 10^{-6}}$[/tex]
[tex]$\Rightarrow \frac{K_2}{K_1}= 1$[/tex]
∴ [tex]$K_2=K_1$[/tex]
So, no this reaction does not seem to follow the thumb rule as its activation energy is very low.
0.254g lead(ii)ethanoate, on adding excess K2CrO4 solution, gave 0.130g of lead(ii)chromate precipitate. what is the percentage composition of Pb in the organic salt? (O = 16, Cr = 52, Pb = 207).
Answer:
32.8%
Explanation:
All of the Pb⁺² species precipitated as lead(II) cromate, PbCrO₄ (we know this as excess K₂CrO₄ was used).
First we convert 0.130 g of PbCrO₄ into moles, using its molar mass:
0.130 g ÷ 323 g/mol = 4.02x10⁻⁴ mol PbCrO₄There's 1 Pb⁺² mol per PbCrO₄ mol, so in total 4.02x10⁻⁴ moles of Pb⁺² were in the ethanoate sample.
We convert those 4.02x10⁻⁴ moles of Pb into grams:
4.02x10⁻⁴ mol * 207 g/mol = 0.083 g PbFinally we calculate the percentage composition of Pb:
0.083 g Pb / 0.254 g salt * 100% = 32.8%8) All of the following statements are true except ________. A) Internal energy is a state function. B) The enthalpy change for a reaction is equal in magnitude, but opposite in sign, to the enthalpy change for the reverse reaction. C) The enthalpy change for a reaction depends on the state of the reactants and products. D) The enthalpy of a reaction is equal to the heat of the reaction. E) Enthalpy is an intensive property.
Answer:
E. Enthalpy is an intensive property Is false.
Explanation:
The false or wrong option in this question is that Enthalpy is an intensive property.
To explain this, I would first explain an intensive property. An intensive property is one that does not depend on the quantity or the mass of matter. Examples are temperature and pressure.
But an extensive property is a property which depends on the mass and the quantity of the system. Enthalpy, volume are all extensive.
Hayley woke up to a hot and humid day but knows it is going to cool off later. What should she expect the weather to be like tonight?
Answer:
It will most likely rain because cool air cannot hold as much moisture as warm air.
Explanation:
I did the quiz !! :)
I really hope this helps!!!!!!!!!!!! :)
Which of the following statements would be an argument against multiculturalism?
(Click all that apply.)
A) Canadians are a mixture of people from various cultural, religious, racial, and ethnic origins. This mixture helps in relations with other countries.
B) Many cultural and ethnic groups have helped build Canada. We should encourage people to preserve their heritage; their traditions are part of Canadian history.
C) Canadians will learn tolerance through being in contact with other cultures. Multiculturalism can help to eliminate discrimination and prejudice.
D) The Canadian government should not spend citizens' tax dollars on multiculturalism. Our taxes are already too high.
Answer:
D
Explanation:
How many grams do 4.5 moles of oxygen atoms weigh
Answer:
71.99100
Explanation:
The mass of oxygen equal to one mole of oxygen is 15.998 grams and the mass of one mole of hydrogen is 1.008 g. 15.998*4.5 = 71.99100
The number of moles of molecules in a 12.0-gram sample of Cl2 is equal too?
Answer:
0.3529moles
Explanation:
no of moles =mass ÷molar mass
molar mass =17+17
=34
12÷34
=0.3529moles
According to the mole concept, the number of moles of molecules in a 12.0-gram sample of Cl₂ is equal to 0.169 moles.
What is a mole?
Mole is defined as the unit of amount of substance . It is the quantity measure of amount of substance of how many elementary particles are present in a given substance.
It is defined as exactly 6.022×10²³ elementary entities. The elementary entity can be a molecule, atom ion depending on the type of substance. Amount of elementary entities in a mole is called as Avogadro's number.
It is widely used in chemistry as a suitable way for expressing amounts of reactants and products.For the practical purposes, mass of one mole of compound in grams is approximately equal to mass of one molecule of compound measured in Daltons. Molar mass has units of gram per mole . In case of molecules, where molar mass in grams present in one mole of atoms is its atomic mass.Number of moles is mass/molar mass= 12/70.90=0.169 moles.
Learn more about mole,here:
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Scientists examine fossils from three different animals. They determine that all three animals share similar structures and
record their observations as follows
• Animal A and animal B have somewhat similar structures
• Animal A and animal C have very similar structures
• Animal B and animal C have very similar structures
The scientists use the similarities to determine the order in which the fossils should appear in the fossil record. Based on the
scientists' observations, which order is the most reasonable?
ABC
ACB
С, В, А
В, А С
Answer:
C,B,A
Explanation:
C has the most similar structure
B has the second most similar structure
A has the least similair structure
Based on the scientists' observations, the order which is the most reasonable is C,B,A.
What are observations?Observations are defined as a set of statements or facts which are recorded while conducting an experiment.Observations are made through sensing changes in the variables of the experiment.
It is specifically defined as an act of knowing or recording the changes in the variables of the experiment.Recording observations holds importance as recording observations avoid the experiment to be repeated over and over again.
It is important to note down observations so that the testing of hypothesis is made easier.There are four types of observations .Observations need to be descriptive and must be written in complete sentences and should include all the numerical data of the experiment.
Learn more about observations,here:
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Help me with this question
Answer:
your cool
Explanation:
owa owa owa owa owa bob
why is weather forecasting important to the people
Answer:
Weather forecasting is important to the people since it helps determine future climate expectations .
What are two things that interact that determine if there is a phase change or not HELP
Answer:
phase change always has two phases in contact during the change. melting => solid & liquid; evaporation (boiling) => liquid & vapor. If only one phase is present, then phase change is not occurring. Also, when two phases are in contact, no temperature changes occur. Only the pure phase demonstrates temperature change when measured. Example, when ice is added to water, at thermal equilibrium (temp = 0°C) the water temp will not continue to change. Only when all the ice has melted will the water temperature demonstrate a measured temperature change.
Explanation:
What is the composition of a universal indicator?
Answer:
The main universal indicator is in the form of a solution and are thymol blue , methyl red , bromothymol blue and phenolphthalein this mixture is important because each component loses or gains protons depending upon the acidity of the solution being tested .
maybe this mighr help u
What is the mass of 2 moles of nitrogen gas, N2?
Answer:
28g
Solution. Hence, 2 moles of nitrogen atoms weigh 28g.
Which of these materials are insulators? Select the THREE (3) that apply.
aluminum can
wool
rubber
iron nail
copper wire
plastic
Answer:
wool ,rubber and copper wire should be correct
Four stereoisomers exist for 4-hexen-3-ol. Draw the structure of the isomer that has the Z configuration around the double bond and the R configuration at the chiral center.
Answer:
Following are the solution to the given question:
Explanation:
Please find the complete question and its graph file in the attachment file.
The isomer having Z specification from around dual connector as well as the chiral center S structure is:
[tex](3S,4Z)-4-Hexen-3-ol[/tex]
An 'H' atom has been at the level of 3rd carbon, and we need to change its configuration, through 'R' to 'S' by CIP notation (under contrast to -OH group).
Answer:
The double bond can have either the E or the Z configuration.
Each of these stereoisomers can exist in either the R or the S configuration at the chiral center for a total of four possible stereoisomers.
An average bushel of apples has a mass of 10 kg and contains 5 dozen apples.
What would be the average mass of 6 apples?
Answer:
Average mass of 6 apple = 1 kg
Explanation:
Given:
Average mass of 5 dozen apple = 10 kg
Find:
Average mass of 6 apple
Computation:
Average mass of 6 apple = [Average mass of 1 apple] x [6 apple]
Average mass of 6 apple = [10/(12 x 5)] x [6]
Average mass of 6 apple = 1 kg
MULTIPLE CHOICE QUESTION
When the frequency increases, the waves
become?
Shorter
Longer
Answer:
Shorter
Explanation:
As a wavelength increases in size, its frequency, and energy (E) decrease. From these equations, you may realize that as the frequency increases, the wavelength gets shorter. As the frequency decreases, the wavelength gets longer. There are two basic types of waves: mechanical and electromagnetic.
what happened to Jodys
father
Answer:
Jody's father was bitten by a poisonous snakes name rattle snake
B) Which of these is NEVER an example of freshwater? A) Pacific Ocean B) Okefenokee Swamp Mississippi River Lake Pontchartrain.
Answer:
Lake pontchartrain
Explanation:
CuCl2(aq) + Na3PO4(aq) =>?
Net ionic equation
PLEASE HELP WORTH 100 POINTS !!!!!
Answer: Imidogen
Explanation: I just looked it up.
Answer:
Imidogen
Explanation:
How does the reactivity of nonmetals change as you move from left to right across the periodic table?
Answer:
Metallic character refers to the level of reactivity of a metal. Non-metallic character relates to the tendency to accept electrons during chemical reactions. Metallic tendency increases going down a group. Non-metallic tendency increases going from left to right across the periodic table.
Explanation:
I hope this helps :)
Answer:
Explanation:
Non metals increases in reactivity!
What is the noble gas configuration of Oganesson?
Answer:
5f14 6d10 7s2 7p6
Explanation:
This is because oganesson is a noble gas and element of group 18 which does not occur or is not produced naturally. It is produced in an experiment. It is a gas at room temperature and it has atomic number of 118. It is harmful and a radioactive gas due to it's radioactive properties and it is produced in small amound