A 0.563 M solution of the salt NaA has a pH of 11.56. Calculate the Ka value for the acid HA. Record your answer in scientific notation to 3 sig figs.

Answers

Answer 1

Answer:

[tex]\displaystyle K_a = 4.24\times 10^{-10}[/tex]

Explanation:

Write the base reaction of NaA with water:

[tex]\displaystyle \text{A}^-_\text{(aq)}+\text{H$_2$O}_\text{($\ell$)}\rightleftharpoons \text{HA}_\text{(aq)} + \text{OH}^-_\text{(aq)}[/tex]

Hence, the equilibrium constant expression for the reaction is:
[tex]\displaystyle K_b = \frac{[\text{OH}^-][\text{HA}]}{[\text{A}^-]}[/tex]

Thus, to find Ka, we can find Kb and use the fact that Ka × Kb = Kw.

From the reaction and initial concentration of NaA, create an ICE chart:

[tex]\begin{tabular}{llllll} & A^- &\text{H$_2$O} & \rightleftharpoons & HA & OH^- \\I & 0.563 M & \---- & & 0 M & 0 M \\C & -\text{ $ x$} & \---- & & +\text{ $x$ M} & + \text{$x$ M} \\E & \text{(0.563 - $x$) M} & \---- & & \text{$x$ M} & \text{$x$ M} \end{tabular}[/tex]

Find [OH⁻] from the given pH:
[tex]\displaystyle \begin{aligned} \text{pH} +\text{pOH} & = 14.00 \\ \\ \text{pOH} & = 14.00 - \text{pH} \\ \\ & = 14.00 - (11.56) \\ \\ & = 2.44 \\ \\ -\log[\text{OH}^-] & = 2.44 \\ \\ [\text{OH}^-] &= 10^{-2.44} \\ \\ & =0.00363 \text{ M}= 3.63\times 10^{-3} \text{ M} = x\text{ M}\end{aligned}[/tex]

Solve for all species concentrations at equilibrium from the found x value:

[tex]\displaystyle [\text{HA}] = [\text{OH}^-] = 3.63\times 10^{-3} \text{ M}[/tex]

And:

[tex]\displaystyle \begin{aligned} \ [\text{A}^-] & = 0.563 - 3.63\times 10^{-3} \text{ M}\\ \\ & = 0.559\text{ M}\end{aligned}[/tex]

Find Kb:

[tex]\displaystyle \begin{aligned} \displaystyle K_b &= \frac{[\text{OH}^-][\text{HA}]}{[\text{A}^-]} \\ \\ & = \frac{(3.63\times 10^{-3})(3.63\times 10^{-3})}{(0.559)}\\ \\ & = 2.36\times 10^{-5}\end{aligned}[/tex]

Find Ka:

[tex]\displaystyle \begin{aligned} K_a\cdot K_b & = K_w \\ \\ K_a & = \frac{K_w}{K_b} \\ \\ & = \frac{(1.00 \times 10^{-14})}{(2.36\times 10^{-5})} \\ \\ &= 4.24\times 10^{-10} \end{aligned}[/tex]

In conclusion:
[tex]\displaystyle K_a = 4.24\times 10^{-10}[/tex]


Related Questions

The table compares some characteristics of two atoms.
Charged Particles
Atom Number of Neutrons Mass Number
х
6
12
Y
7
13
Use the table to determine the number of protons for each atom. Then, choose the statement below that is true about the two atoms.

Answers

The number of protons in X would be 6 while that of Y would also be 6. Thus, the two atoms would be isotopes of the same element.

Atomic properties of atoms

The mass number of an atom is the sum of protons and neutrons present in the atom.

For X with mass number 12 and neutron number 6, the number of protons would be:

                                 12 - 6 = 6 protons

For Y with mass number 13 and neutron number 7, the number of protons would be:

                                     13 - 7 = 6 protons.

Thus, both atoms have the same number of protons, meaning that they are likely isotopes of the same element.

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If 32.00 mL of a solution of Ca(OH)2 requires 16.08 mL of a 2.303 M solution of HNO2 for complete titration, what is the molarity of the Ca(OH)2 solution?

Answers

For the equilibrium that exists in an aqueous solution of nitrous acid ... calcium hydroxide is dissolved in water until the pH of the solution is 11.44.

Will a precipitate form if you mix 75.0 mL of a NaOH solution with pOH of 2.58 if it is mixed with 125.0 mL of a 0.0018 M MgCl2 solution

Answers

A precipiatate of mass 0.013 g is formed when you mix 75.0 mL of a NaOH solution with pOH of 2.58 and  125.0 mL of a 0.0018 M MgCl2 solution

What is stoichiometry?

In stoichiometry, calculations are made based on mass - mole or mole - volume relationships. First we must put down the balanced reaction equation; 2NaOH(aq) + MgCl2(aq) -----> Mg(OH)2(s) + 2NaCl(aq)

Now Ionically;

2OH^-(aq) + Mg^2+(aq)  -----> Mg(OH)2(s)

Concentration of OH^- = Antilog (-2.58) = 2.6 * 10^-3 M

Number of moles of OH^- = 2.6 * 10^-3 M * 75/1000 = 0.000195 moles

Concentration of Mg^2+ = 0.0018 M

Number of moles of Mg^2+ =0.0018 M * 125/1000 = 0.000225 moles

Since;

1 mole of Mg^2+ reacts with 2 moles of  OH^-

x moles of Mg^2+ reacts with 0.000195 moles of  OH^-

x = 0.0000975 moles

Mg^2+  is the limiting reactant.

1 mole of Mg^2+ yields 1 mole of the precipitate

0.000225 moles of Mg^2+ yields 0.000225 moles of precipitate.

Hence, a precipitate is formed.

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15.0 g of water at 0.0 °C are added to 40.0 g of water at 40.0 °C. What is the final
temperature of the mixture?

Answers

Answer:

40.0 c

Explanation:

Answer:

29.09 degree Celsius is final temperature

How many molecules are equivalent to 0.5 mol 02 molecule?​

Answers

No of molecules

Moles×Avagadro no0.5×6.022×10²³3.011×10²³molecules

Note that

For any element ,1 mol of them contains 6.022×10²³ molecules or atoms

match the following ​

Answers

Answer:

1 FOSSIL FUEL WITH A2 COMBUSTION WITH D3 PETROL WITH C4 GOBAR GAS WITH E5 FIRE EXTINGUISHER WITH B

PLEASE MARK ME BRAINLIEST IF MY ANSWER IS CORRECT PLEASE

........................

Answers

Answer:

no questions

it's just all dots here

Explain contact process​

Answers

Answer:

contact process, modern industrial method of producing sulfuric acid; it has largely replaced the chamber, or lead-chamber, process. Sulfur dioxide and oxygen, passed over a hot catalyst, unite to form sulfur trioxide, which in turn combines with water to make sulfuric acid.

Determine the type of reaction: AgNO3 + Cu --> Cu(NO3)2 + Ag

a. Double displacement
b. single displacement
c. Decomposition
d. Synthesis

Answers

Answer:

b. single displacement

Problem To Solve:
Scenario: you have a very bad head-ache so you run to the pharmacy to grab some medicine and are immediately over-whelmed with your options. You decide to buy the cheapest option to cure your headache.
Availability:
Excedrin is available as a 200 caplet bottle for $15.51 and each caplet contains 250- mg of acetaminophen (the active ingredient in Excedrin).
Advil is available as a 300 tablet bottle for $15.00 and each tablet contains 200-mg of Ibuprofen (the active ingredient in Advil).
Tylenol is available as a 225 pill bottle for $14.97 and each pill contains 500mg of a paracetamol (the active ingredient in Tylenol).
Dosage Information:
Acetaminophen is dosed as 240 mg per 35 pounds of body mass.
Ibuprofen is dosed at 113 mg per 25 pounds of body mass.
Paracetamol is dosed at 102mg per 15 pounds of body mass.
Active ingredient information:
Acetaminophen has the chemical formula: C8H9NO2
Ibuprofen has the chemical formula C13H18)2.
Paracetamol has the chemical formula C8H9NO2.
How:
Calculate the cost of treating your own headache for each medicine based on your own body weight = 130 pounds.
Clearly write out and organize all the conversion factors, then write out the conversion for each medicine. Once you have concluded the cheapest option for curing your headache, calculate the cost per individual molecule of your pain reliever.
Please help me solve this and write all the conversion factors, and write out the conversion for each medicine. Thank you!

Answers

Based on the drug dosage provided, cheapest drug for treating headache is Tylenol at a cost of 3.34×10^-23 $/molecule.

What is a drug dosage?

A drug dosage is the amount of a drug taken by an individual that produces a therapeutic effect.

The dosage of each drug is given below:

Acetaminophen is dosed as 240 mg per 35 pounds of body mass.Ibuprofen is dosed at 113 mg per 25 pounds of body mass.Paracetamol is dosed at 102mg per 15 pounds of body mass.

Amount of each drug required by individual is as follows:

Acetaminophen = 240 mg/35 × 130 = 891.43 mg

Ibuprofen = 113 mg/25 × 130= 587.6 mg

Paracetamol = 102mg/15 × 130 = 884 mg

Cost of drug per mg of active ingredient is as follows;

Excedrin =  $15.51/(200 * 250 mg) = 0.0003102 $/mg

Advil = $15/(300 * 200mg) = 0.00025 $/mg

Tylenol = $14.97/(500mg × 225) = 0.000133 $/mg

Cost of each drug for treatment of headache:

Excedrin = 0.0003102 $/mg × 891.43 mg = $0.278

Advil = 0.00025 $/mg × 587.6 mg = $0.147

Tylenol = 0.000133 $/mg × 884 mg = $0.118

Thus, Tylenol is the cheapest drug for treating headache.

Molar mass of paracetamol = 151 g = 151000 g

There are 6.02 × 10^23 molecules in 151000 mg of paracetamol.

Cost per molecule = 0.000133 $/mg × (15000 mg/6.02 × 10^23)

Cost per molecule = 3.34 × 10^-23 $/molecule

Therefore, the cheapest drug for treating headache is Tylenol at a cost of 3.34×10^-23 $/molecule.

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The reaction Na3PO4 + 3HCl → 3NaCl + H3PO4 produces 42.7 g of NaCl. How many grams of Na3PO4 are needed?

Answers

Answer:

14.23

Steps given below in the picture

I hope my answer helps you.


the carbon atom which becomes asymmetric when the straight chain form of monosaccharide change into ring form is known as____\

Answers

Answer:

CARBOHYDRATES AND CARBOHYDRATE METABOLISM


Which is the correct step(s) for this reaction mechanism?
O NO2 + CO2 + CO NO + CO2
O step 1: NO2 + NO2 → NO + NO3 (slow)
step 2: NO3 + CO → NO2 + CO2 (fast)
O step 1: NO + NO3-NO + NO3 (slow)
step 2: NO3 + CO → NO + CO2 (fast)
O step 1: 2N02 + NO 2NO + NO3 (slow)
step 2: NO3 + CO → 2NO2 + CO2 (fast)

Answers

The reaction mechanims shows the sequence of steps through which a reaction occurs. The reaction mechanism for this reaction is;

step 1: NO2 + NO2 → NO + NO3 (slow)

step 2: NO3 + CO → NO2 + CO2 (fast)

What is reaction mechanism?

We have to note that not all reactions occur in a single reactive encounter. If a reaction occurs in a single reactive encounter then it is called an elementary reaction.

The reaction mechanim shows the reaction sequence of a non elementary reaction. The correct mechanims of this reaction is shown as;

step 1: NO2 + NO2 → NO + NO3 (slow)

step 2: NO3 + CO → NO2 + CO2 (fast)

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What is the numbers of molecules for 65.8g of CO2?

Answers

Answer:

One gram of carbon dioxide contains 13.6 x 10²¹ number of molecules.

Explanation:

Answer:

1.50 moles

Explanation:

use dinemential analysis

find the molar mass

Balance the following equation. Fill in the blanks

( ? )NaCl + ( ? ) AgNO3 → ( ? )AgCl + ( ? ) NaNO3

Answers

NaCl+AgNO_3-->AgCl+NaNO_3

on both sides

Na=1Ag=1Cl=1NO_3=1

Hence it's balanced already

what happens when ethanol reacts with alkaline potassium permanganate?​

Answers

Answer:When ethanol is oxidised with alkaline potassium permanganate (alkaline KMnO 4) or acidified potassium dichromate (acidified K 2 Cr 2 O 7), ethanoic acid is formed. Alkaline potassium permanganate and acidified potassium dichromate are strong oxidising agents, as they provide oxygen for oxidising other substances in the reaction

Explanation:

When ethanol is handled with alkaline potassium permanganate, alkaline potassium permanganate reacts the ethanol to generate ethanoic acid.

Why do scientists listen to ocean around plate boundary?

Answers

Answer:

Scientists discovered that when the locations of earthquakes were plotted on a world map, these locations occurred in a pattern, or variety of patterns.

Explanation:

What is the theoretical yield of sodium chloride for the reaction of 55.0 g of Na
D
with 67.2 g Cl2?
g
a. 1.40 x 102 g NaCl
b. 111 g NaCl
c. 55.4 g NaCl
222 g NaCl

Answers

[tex]\mathfrak{\huge{\orange{\underline{\underline{AnSwEr:-}}}}}[/tex]

Actually Welcome to the concept of Physical chemistry, and Stochiometry.

So we balance the equation as,

2Na + Cl2 ===> 2NaCl

The required reaction is as:

2Na+ Cl2 = 2NaCl

2 moles Na = 2×23 g = 46g,1 mole Cl2 = 2×35.5g=71g

Now,71g Cl2 reacts with 46g Na,

Therefore, 67.2g Cl2 reacts with 46×67.2/71= 43.54g Name

The rest Na = (55–43.54)g=11.46g

That means Cl2 is a limiting reactant.

Again,2 moles NaCl=2(23+35.5)g=117g

Then,71g Cl2 produce 117g NaCl

Therefore,67.2g Cl2 produce 117×67.2/71 = 110.74g NaCl

hence the correct option is, b.) 111 g NaCl

Its B hope it helps:))

how do x rays use electromagnetic waves?

Answers

Answer:

X-rays are a form of electromagnetic radiation, similar to visible light. Unlike light, however, x-rays have higher energy and can pass through most objects, including the body. Medical x-rays are used to generate images of tissues and structures inside the body.

Explanation:

Answer:

Explanation:Los rayos X son un tipo de radiación llamada ondas electromagnéticas. Las imágenes de rayos X muestran el interior de su cuerpo en diferentes tonos de blanco y negro. Esto es debido a que diferentes tejidos absorben diferentes cantidades de radiación.

El uso más común de los rayos X es para ver fracturas (huesos rotos), pero también se utilizan para otros usos. Por ejemplo, las radiografías de tórax pueden detectar neumonía. Las mamografías utilizan rayos X para detectar el cáncer de mama.



A 0.506 g sample of solid calcium hydroxide was dissolved in some water and then titrated with 28.85 mL of hydrochloric acid to neutralize. What was the molarity of the hydrochloric acid (M)? (Start by writing and balancing the reaction.)

Answers

A 0.506 g sample of solid calcium hydroxide was dissolved in some water and then titrated with 28.85 mL of hydrochloric acid to neutralize, then the molarity of HCl is 0.471 M.

How do we calculate molarity?

Molarity will be calculated by using the below equation as:

M = n/V, where

V = volume of solvent

n is the moles of solute and it will be calculated by using the below equation:

n = W/M, where

W = given mass

M = molar mass

Given chemical reaction is:

Ca(OH)₂ + 2HCl → CaCl₂ + 2H₂O

Moles of Ca(OH)₂ = 0.506g / 74.093g/mol = 0.0068 mol

From the stoichiometry of the reaction:

0.0068 moles of Ca(OH)₂ = reacts with 2×0.0068 = 0.0136 moles of HCl

Given volume of HCl = 28.85mL = 0.02885 L

On putting values on the molarity equation, we get

M = 0.0136 / 0.02885 = 0.471 M

Hence required molarity of HCl is 0.471 M.

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Which of the following is not a reason the nitrogen cycle is important to life on Earth?
a.
All living things need nitrogen to make proteins.
b.
Nitrogen is radioactive if it doesn’t go through the cycle.
c.
Organisms cannot use nitrogen directly.
d.
All living things need nitrogen to make DNA.

Answers

Answer:

b

Explanation:

What is the compound name for this compound structure?

Answers

The compound name for the compound structure given in the question is 2, 3-dimethlypentane

IUPAC nomenclature

The international union of pure and applied chemistry (IUPAC) has organised a principle by which organic compounds are named. This principle includes:

Identify the functional group Locating the longest continuous carbon chain. This gives the parent name of the compound. Identified the substituent groups attached Give the substituent groups the lowest low count Combine the above to get the name

How to name the compound The functional group is alkane since it contains only single bonds The longest continuous carbon chain is 5. Thus the parent name is pentane. Two methyl (CH₃) groups are attached The methyl (CH₃) groups are located at carbon 2 and 3The name of the compound is 2, 3-dimethlypentane

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2. If you were to take a radio to the moon, which of the following would
correctly describe the changes to its mass and weight?
A. Its mass and weight would not change.
B. Its mass would increase, and its weight would remain the same
C. Its weight would increase, and its mass would remain the same
D. Its weight would decrease, and its mass would remain the sam

Answers

A) Its mass and weight would not change.
Explanation: I got it right;)

How are potential and kinetic energy different?

Potential energy is stored in a battery, and kinetic energy is released thermal energy that causes electricity.

Potential energy is stored in an object, and kinetic energy is released mechanical energy that causes motion.

Kinetic energy is the movement of an object, and potential energy is released electrical energy when an object moves.

Kinetic energy is stored in an object, and potential energy is released mechanical energy that causes motion.

Answers

Answer:

b) potential energy is stored in an object, and kinetic energy is released mechanical energy that causes motion.

Explanation:

potential energy is stored because it is the possible energy of an object if a force is acted upon it. on the other hand, kinetic energy is essentially when potential energy is being acted upon or changed.

Answer: The second option

Explanation: For example, if a ball is sitting at the top of a hill, it has a lot of potential energy. If it then falls off, potential energy will turn into kinetic energy and the ball will roll down the hill.


20 L of nitrogen gas are collected at a temperature of 50°C and 2 atm. How many grams of nitrogen gas were collected?

Answers

Answer:

0.1077 grams

Explanation:

First we will employ the ideal gas law to determine the number of moles of nitrogen gas.

PV=nRT

P=2 atm

V=20L

R=0.08206*L*atm*mol^-1*K^-1

T=323.15 K

Thus, 2atm*20L=n*0.08206*L*atm*mol^-1*K^-1*323.15K

K, atm, and L cancels out. Thus n=2*20mol/0.08206*323.15=1.5 moles

Lastly, we must convert the number of moles to grams. This can be done by dividing the number of moles by the molar mass of nitrogen gas, which is 14 grams.

1.5/14=0.1077 grams

HCl(?) + H2O(?) → H3O+(?) + Cl-(?)

What is the phase label on Cl-?

Answers

Answer:

H30,+ion is known as Hydroniom Ion

Explanation:

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everyday

brainless this answer is correct

Lithium Oxide (Li2O) is a highly reactive chemical species which reacts to give electrons to other atoms, following a general reaction scheme of:

Li2O + X → LiX + O2
Data were collected from a series of reactions involving lithium oxide and one other element.



Which statement is best supported by the evidence in the table?



The ionization energy of oxygen is lower than that of boron, beryllium, and lithium.


The electronegativity of oxygen is lower than that of fluorine, carbon, and nitrogen.


The electronegativity of oxygen is higher than that of boron, beryllium, and lithium.


The ionization energy of oxygen is higher than that of fluorine, carbon, and nitrogen.

Answers

Answer:

I think that A is the correct answer might not be

PLEASE MARK ME BRAINLIEST IF MY ANSWER IS CORRECT PLEASE

What is vapor pressure?

Answers

Answer: pressure exerted by vapor

Explanation:

what can you say about the acceleration when the pressure decreases from left to right

Answers

When the pressure decreases from left to right, the acceleration also decreases.

What is Acceleration?

This is defined as the rate at which velocity changes with time and it has a direct relationship with pressure.

This however means that when pressure decreases there will be a corresponding decrease in acceleration and vice versa.

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what is haber's process?​

Don't spam...​

Answers

Answer:

The Haber process, also called the Haber–Bosch process, is an artificial nitrogen fixation process and is the main industrial procedure for the production of ammonia today. It is named after its inventors, the German chemists Fritz Haber and Carl Bosch, who developed it in the first decade of the 20th century. 

Answer:

a catalytic process for synthesizing ammonia from nitrogen and hydrogen

Explanation:

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