Calculate the pH at the equivalence point for the titration of 0.200 M 0.200 M methylamine ( CH 3 NH 2 ) (CH3NH2) with 0.200 M HCl . 0.200 M HCl. The K b Kb of methylamine is 5.0 × 10 − 4 . 5.0×10−4. pH =

Answers

Answer 1

Answer:

pH = 5.85

Explanation:

The reaction of methylamine with HCl is:

CH₃NH₂ + HCl → CH₃NH₃⁺ + Cl⁻

As the titration was made with two solutions with the same molarity, the final concentration of the CH₃NH₃⁺ ion is 0.100M ([CH₃NH₃⁺] = 0.100M)

Then, the conjugate acid will be in equilibrium with water as follows:

CH₃NH₃⁺(aq) + H₂O(l) ⇄ CH₃NH₂(aq) + H₃O⁺(aq)

And the equilibrium constant, Ka, of this reaction is:

Kw/Kb = Ka =  1.0x10⁻¹⁴ / 5.0x10⁻⁴= 2x10⁻¹¹

2x10⁻¹¹ =  [CH₃NH₂] [H₃O⁺] / [CH₃NH₃⁺]

As both CH₃NH₂ and H₃O⁺ comes from the same equilibrium we can say:

[CH₃NH₂] = [H₃O⁺] = X

And as we know [CH₃NH₃⁺] = 0.100M:

2x10⁻¹¹ =  [X] [X] / [0.100M]

2x10⁻¹² = X²

X = 1.414x10⁻⁶M = [H₃O⁺]

And as pH= -log [H₃O⁺]

pH = 5.85


Related Questions

what are the twa parts of central nervous system ?​

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the brain and the spinal cord

Answer:

The nervous system has two main parts: The central nervous system is made up of the brain and spinal cord.

Explanation:

Describe how chemical reactions are affected by reaction conditions
of monction?

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Answer:

hope his helps

Explanation:

Mention the factors affecting the rate of reaction

There are four main factors that can affect the reaction rate of a chemical reaction:

Reactant concentration. Increasing the concentration of one or more reactants will often increase the rate of reaction. ...

Physical state of the reactants and surface area. ...

Temperature. ...

Presence of a catalyst.

What is the hydrogen ion concentration ([H']) of a substance with a pH of 4.91?

Answers

Answer:

The pH of a solution is a measure of the concentration of hydrogen ions in the solution. A solution with a high number of hydrogen ions is acidic and has a low pH value. A solution with a high number of hydroxide ions is basic and has a high pH value. The pH scale ranges from 0 to 14, with a pH of 7 being neutral.

Which of the following would be defined as an exact number?
A. bronze is 12.5% by mass tin
B. 25 ml
C. 50.00 cm
D. 1.000 liters

Answers

a because that is the only anwser that would make sense

Which superpower would you have for the rest of your life?
The ability to fly
Teleportation
Super speed
Super strength
Invisibility
Time travel
Or be normal and have nothing special

Answers

time travel is the best option

What substance is oxidized in the following reaction? 4HCl + MnO2 → Cl2 + 2H2O + MnCl2

Answers

Answer:

Cl⁻ was oxidized.

Explanation:

4HCl + MnO₂ → Cl₂ + 2H₂O + MnCl₂

Oxidation can be defined as the process in which the oxidation number of a substance increases.

On the left side of the equation, Cl has a charge of -1 (in HCl); while on the right side of the equation Cl has a charge of 0 in Cl₂.

Thus, Cl⁻ was oxidized.

A chemist has a sample of 1.88 M HCl. What volume of the sample does he require to prepare 200 mL of 0.45 M HCl?

Answers

Answer: v = 200 ml · 0.45 M/ 1.88 M

Explanation: when solution is diluted, amount of substance

is same and n= c · V v1 = v2 · c2 / c1

The appropriate answer is "47.87 mL".

Given values are:

Concentration of undiluted HCl, [tex]C_1=1.88 \ M[/tex]Concentration of diluted HCl, [tex]C_2=0.45 \ M[/tex]Volume of diluted HCl, [tex]V_2=200 \ mL[/tex]

By using the dilution equation, we get

→ [tex]C_1V_1=C_2V_2[/tex]

or,

→     [tex]V_1=\frac{C_2V_2}{C_1}[/tex]

By substituting the given values, we get

→          [tex]=\frac{0.45\times 200}{1.88}[/tex]

→          [tex]=\frac{90}{1.88}[/tex]

→          [tex]= 47.87 \ mL[/tex]

Thus the above answer is correct.

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Give an example of an electrolyte ​

Answers

Answer: sodium chloride water solution

Explanation: Eelctrolyte contains cations and anions which can

Transfer charge

Answer:

some energy drinks like powerade or Gatorade, and some juice drinks to.

I don’t understand please help

Answers

It’s C)H2SO4
Good luck
I agree the answer is C according to my research about it

How many moles of silver atoms are in the piece of jewelry?

Answers

moles contains 6.02 x 10^23 silver atoms

so moles = (5.29 X 10^22)/ (6.02 x 10^23)
= 5.29/6.02 x 1/10

The number of moles of silver atoms in the piece of jewelry is 0.08784 moles

Here is the complete question:

Suppose a piece of jewelry contains 5.29 × 10²² atoms of silver  . How many moles of silver atoms are in the piece of jewelry?

From the question,

A piece of jewelry contains 5.29 × 10²² atoms of silver.

To determine number of moles of silver atoms in the piece of jewelry,

We will use the formula

[tex]Number \ of \ moles = \frac{Number \ of \ atoms }{Avogadro's \ number}[/tex]

From the question

Number of atoms of silver = 5.29 × 10²² atoms

and

Avogadro's number = 6.022 × 10²³ atoms/mole

∴ [tex]Number \ of \ moles \ of \ silver \ atoms= \frac{5.29 \times 10^{22} }{ 6.022 \times 10^{23} }[/tex]

Number of moles of silver atoms = 0.08784 moles

Hence, the number of moles of silver atoms in the piece of jewelry is 0.08784 moles

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Ca3(PO4)2 + 3H2SO4  3CaSO4 + 2H3PO4.
What mass of concentrated H2SO4 (98% by mass) must be used to react completely
with 100.00 g of calcium phosphate?

Answers

If anything isn’t obvious, don’t hesitate to ask me
Check the attached photo out...

100g  

H2SO4 = 3x98x100/310 = 94.84g

used mass of h2so4x100/all mass of H2so4 = 98%

yx100/98=94.84x100/98 = 96.81.

Check the attached photo for clear answer.

What is the use of calcium phosphate?

It may be used to treat conditions caused by low calcium levels such as bone loss (osteoporosis), weak bones (osteomalacia/rickets), decreased activity of the parathyroid gland (hypoparathyroidism), and certain muscle diseases (latent tetany).

Is calcium phosphate good for health?

About Calcium Phosphate Supplements

It aids in healthy bone development and is crucial from infancy to adulthood. But, calcium does more than build strong bones. It's also very important for healthy digestion. Calcium aids in bile acid metabolism, excretion of fatty acids, and healthy gut microbiota.

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Which of the following statements is correct?

A. 2 moles of O2 is equal to 64 g of O2.

B. 2 moles of O2 is equal to 32 g of O2.

C. 2 moles of O2 is equal to 2 g of O2.

D. 1 moles of O2 is equal to 2 g of O2.

Answers

Answer:

pretty sure its B but if not I'm sorry

2 moles of O₂ is equal to 64 g of O₂ is the only correct statement among the given statements. Hence, Option (A) is correct. It can be solved by mole concept

What is Mole concept ?

The mole, symbol mol, is the SI base unit of amount of substance.

The quantity amount of substance is a measure of how many elementary entities of a given substance are in an object or sample.

formula ;

n = given weight / molecular weight

  = 64 / 32

  = 2 moles

Therefore, 2 moles of O₂ is equal to 64 g of O₂ is the only correct statement among the given statements. Hence, Option (A) is correct.

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How can the speed of solvent molecules be slowed down?

A.by increasing the temperature

B. by increasing the surface area of the solute

C. by increasing the pressure

D. by decreasing the temperature

E. by decreasing the surface area of the solute

Answers

Answer:

D

Explanation:

When molecules absorb energy they speed up and have a more forceful collision with solute molecules.

Who ever has the best answer to this question gets brainliest

Answers

Answer:

"Conduction from the sun heating the metal slide" is the answer

Explanation:

You heat water and olive oil in two separate pans for a delicious new pasta recipe. The pans are the same temperature, but only the water is boiling! Why?

A
Olive oil has weaker intermolecular forces than water. This makes the intermolecular forces in oil easier to break, and keeps the molecules stuck together in a liquid state.

B
Water has weaker intermolecular forces than olive oil. This makes the intermolecular forces easier to break, allowing the individual water molecules to separate and change to a gas.

C
Water is losing electrons more quickly than olive oil is. The electrons float to the surface of the water, and their movement allows the phase change to happen.

Answers

Answer:

I think A is the correct answer

Answer: the answer is B 100%

Which environment can occur for a short while and usually found in low level areas along rivers, lakes, and streams?

Desert
Mountain
Rainforest
Wetland

Answers

the answer is wetland

Answer:The answer is wetland or rainforest

Explanation:

It’s wetland or rainforest because its with the tropical zone and there will be no such thing as desert and mountain have those but the rainforest is with the tropic to so Goodluck with any of your test and hope this did not make sense xdd

What is the percent composition of hydrogen in glucose

Answers

Answer:

67%

Explanation:

Thus the % composition of glucose by mass is carbon 40.0 % oxygen 53.3 % hydrogen 6.7 % in this way, the % composition by mass of any compound can be calculated provided that is formed is known.

pleaaaaase helppppppppppppp ASAP

Answers

Answer:

Explanation:

a) The forward reaction is exothermic, hence when temperature is increased the equilibrium shift towards the reactants side to get rid of the excess energy. This will mean that more reactants are produced decreasing yield

b) There are a fewer number of moles of gas on the right side compared to the left side (Just count the coefficients before each compound) so a higher pressure will mean that the equilibrium will shift towards the products side in order to decrease the pressure. This will mean that more products are formed increasing yield

c) When something is powdered it's surface area to volume ratio increases. A higher surface area means that the particles around it have more area to work on so the frequency of collisions will increase increasing the rate of reaction. This is why iron is powdered.

Using the periodic table, choose the more reactive nonmetal.
Te or O

Answers

Answer:

answer is TE

Explanation:

Answer:

Tellurium is more reactive than Oxygen

How many moles is 2.04x1023 molecules of NH3?

Answers

Answer:

We will Multiply the number of moles with Avagadro's number

So it will be (2.04×1023)×6.022×10^23

or 2.04×1023 NA

NA means Avagadro's number

Balance C3H8 + O2 + CO2 + H2O

Answers

Assuming the second plus sign is a typo and was meant to be a reaction arrow, this would be the balanced equation:

C3H8 + 5O2 —> 3CO2 + 4H2O

PLEASE PLEAS HELP I REALLY NEED IT

Answers

Answer:  

A i took the quiz

Explanation:

A 20.0 L container at 303 K holds a mixture of two gases with a total pressure of 5.00 atm. If there are 2.00 mol of Gas A in the mixture, how many moles of Gas B are present?

Answers

PV = nRT —> n = PV/RT
P = 5.00 atm
V = 20.0 L
R = 0.08206 L atm / mol K
T = 303 K

n = (5.00 • 20.0)/(0.08206 • 303)
= 4.02 mol = A + B
A = 2.00 mol
B = 2.02 mol

The number of moles of Gas B in the gas mixture is equal to 2.00 mol.

What is the ideal gas equation?

The ideal gas equation can be explained as an equation that describes the state of an ideal gas. This equation gives the product of the volume and pressure of ideal gas equal to the multiplication of the universal gas constant, absolute temperature, and moles of gas.

The mathematical form of the ideal gas equation mentioned below:

PV = nRT

Where P is the pressure, V is the volume, n is the moles, and R is the gas constant.

Given, the volume of the gas mixture, V = 500 ml = 0.5 L

The temperature of the gas mixture, T = 303 K

The pressure of the gas mixture = 5 atm

The value of gas constant, R =0.082 atmL/K mol

Substituting the values R, V, P, and T in the ideal gas law, we get:

The number of moles of the gas mixture, n = PV/RT

n = 5 ×20/(0.082 × 303)

n = 4.00 mol

The total number of moles of gas mixture = 4.00 mol

The moles of Gas A = 2.00 mol

The moles of Gas B = 4 - 2 = 2.00 mol

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How many grams of CaCl 2 are in .48 moles ?

Answers

Answer:

We assume you are converting between moles CaCl2 and gram. You can view more details on each measurement unit: molecular weight of CaCl2 or grams This compound is also known as Calcium Chloride. The SI base unit for amount of substance is the mole. 1 mole is equal to 1 moles CaCl2, or 110.984 grams.

The mass of calcium chloride is 53.27 grams.

Given:

Moles of CaCl₂ = 0.48 moles

Molar mass of CaCl₂ = 110.98 g/mol

To find:

Mass of CaCl₂ = ?

Number of moles:

It is defined as given mass over molar mass.

Number of moles  =  Mass / Molar mass

Mass = Number of moles * Molar mass

Mass = 0.48 moles  * 110.98 g/mol

Mass = 53.27 grams

Thus, the mass of calcium chloride is 53.27 grams.

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g You are given a 1.25 gram mixture of calcium nitrate and calcium chloride. You dissolve this mixture in 200.0 mL of water and add an excess of 0.300 M silver nitrate. You collect and dry the white precipitate which forms and find it has a mass of 0.535 grams. Calculate the percent calcium chloride by mass in the original mixture.

Answers

Answer:

16.51%

Explanation:

The reaction that takes place is

CaCl₂(aq) + 2AgNO₃(aq) → 2AgCl(s) + Ca(NO₃)₂(aq)

Meaning that the white precipitate that formed is AgCl. Now we convert 0.535 g of AgCl into moles, using its molar mass:

0.535 g ÷ 143.43 g/mol = 0.00373 mol AgCl

Then we convert 0.00373 moles of AgCl into moles of CaCl₂, using the stoichiometric coefficients:

0.00373 mol AgCl * [tex]\frac{1molCaCl_2}{2molAgCl}[/tex] = 0.00186 mol CaCl₂

We convert moles of CaCl₂ into grams, using its molar mass:

0.00186 mol CaCl₂ * 110.98 g/mol = 0.206 g

Finally we calculate the percent of CaCl₂ by mass in the original mixture:

0.206 g / 1.25 g * 100% = 16.51%

The percent calcium chloride by mass in the original mixture is 16.4%

The equation of the reaction between calcium nitrate and silver chloride is:

[tex]\mathbf{CaCl_2 + 2AgNO_3 \to 2 AgCl+Ca(NO_3)_2}[/tex]

Given that;

the weight mass of the white precipitate formed is = 0.535 grams

the number of moles of the precipitated AgCl is:

= 0.535 g / 143.32 g/mol

= 0.0037 moles

From the above reaction, If 2 moles of AgCl are formed  by 1 mole of CaCl2

Then, 0.0037 moles of AgCl will form (0.0037 × 1)/2 moles of CaCl2.

0.0037 moles of AgCl will form 0.00185 moles of CaCl2.

Now, we can say that the number of moles of CaCl2 present in the mixture is =  0.00185 moles

Mass amount of CaCl2 present = 0.00185 moles × 110.98 g/mol

Mass amount of CaCl2 present = 0.205 grams

Finally, the mass percentage   [tex]\mathbf{=\dfrac{0.205}{1.25}\times 100\%}[/tex]

= 16.4%

Therefore, we can conclude that the percent calcium chloride by mass in the original mixture is 16.4%

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Chlorine and hydrogen gas react to form hydrogen chloride as shown in the following reaction Cl 2 ( g)+H 2 (g)--->2HCl (g) Given a 7.10 g sample of chlorine (MM =71.0 g/mol) , how many grams of hydrogen chloride (MM =36.5 g/mol) is produced, assuming the reaction goes to completion? a. 7.10 g 6.3.65 9 c. 5,68 g d 7.300​

Answers

Answer:

it should be 7.300 sorry if I am wrong

Answer:

The answer is 115

Explanation:

Teacher walked me through it.

need help asap, In this reaction how many units of B are required to form 40 units of C? A+2B--->C​

Answers

Answer:

80 units B

Explanation:

Equation for the reaction is given below:

A + 2B —> C

From the equation above,

2 units of B reacted to produce 1 unit to C.

Finally, we shall determine the unit of B needed to produce 40 units of C. This can be obtained as follow:

From the equation above,

2 units of B reacted to produce 1 unit to C.

Therefore, x unit of B will react to produce 40 units of C i.e

x unit of B = 2 × 40

x unit of B = 80 units

Thus, 80 units B is needed for the reaction.

If you just want points just say so this can lead me to failing 10th if I don’t pass this quiz so if you don’t know just say so I understand you want points I just don’t wanna fail Ocean acidification is a consequence that occurs when the equilibrium between CO2
CO
2
concentrations in the ocean and atmosphere starts shifting. What is the pH of pure water?

Question 8 options:

13, basic


7, neutral


4, acidic

Answers

Answer:

13,basic would be your answer!

Explanation:


How many moles of chlorine atoms are there in 0.5 mol of titanium (III) chloride?​

Answers

Answer:

it is your answer..... if it is helpful plzz like and comment.....

Identify the type of reaction.

Al + MgSO4 = Al2(SO4)3 + Mg

Answers

Answer: its combustion

Explanation:

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