Answer:
pH = 2.10
Explanation:
We name an acid as diprotic because it can release two protons:
H₂A + H₂O ⇄ H₃O⁺ + HA⁻ Ka₁
HA⁻ + H₂O ⇄ H₃O⁺ + A⁻² Ka₂
We propose the mass balance:
Analytical concentration = [H₂A] + [HA⁻] + [A⁻²]
As Ka₂ is so small, we avoid the [A⁻²] so:
0.18 M = [H₂A] + [HA⁻]
But we can not avoid the HA⁻, because the Ka₁. Ka₁'s expression is:
Ka₁ = [H₃O⁺] . [HA⁻] / [H₂A]
We propose the charge balance:
[H₃O⁺] = [HA⁻] + [A⁻²] + [OH⁻]
As we did not consider the A⁻², we can miss the term and if
Kw = H⁺ . OH⁻
We replace Kw/H⁺ = OH⁻. So the new equation is:
[H₃O⁺] = [HA⁻] + Kw / [H₃O⁺]
The acid is so concentrated, so we can avoid the term with the Kw, so:
[H₃O⁺] = [HA⁻]
In the mass balance we would have:
0.18 M = [H₂A]
We replace at Ka₁
Ka₁ = [H₃O⁺] . [HA⁻] / [H₂A]
Ka1 . 0.18 / [H₃O⁺] = [HA⁻]
We replace at the charge balance:
[H₃O⁺] = Ka1 . 0.18 / [H₃O⁺]
[H₃O⁺]² = 3.4×10⁻⁴ . 0.18
[H₃O⁺] = √(3.4×10⁻⁴ . 0.18)
[H₃O⁺] = 7.82×10⁻³
- log [H₃O⁺] = pH → - log 7.82×10⁻³
pH = 2.10
Following are the calculation to the pH:
For First ionization:
[tex][H^+] = (K_{a1} \times C)^{\frac{1}{2}}[/tex]
where
C = initial concentration of acid [tex]= 0.18\ M[/tex]
[tex][H^{+}] = (3.4 \times 10^{-4} \times 0.18 \ M)^{\frac{1}{2}}\\[/tex]
[tex][H^{+}] = 0.007\ M[/tex]
For Second ionization:
[tex][H^{+}] = K_{a2} \\\\[/tex]
[tex][ H^{+} ] = 6.7 \times 10^{-9}\ M \\[/tex]
[tex]Total [H^{+}] = 0.007\ M + 6.7 \times 10^{-9}\ M\\\\Total [H^{+}] = 0.007 \ M[/tex]
[tex]pH = -\log[H^+] \\\\pH = -\log(0.007 \ M)\\\\pH = 2.15[/tex]
Therefore, the pH is "2.15".
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Cuci
what is the formula?
Answer:
Copper(I) chloride, commonly called cuprous chloride, is the lower chloride of copper, with the formula CuCl. The substance is a white solid sparingly soluble in water, but very soluble in concentrated hydrochloric acid. Impure samples appear green due to the presence of copper(II) chloride.
Explanation:
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Convert a speed of 933 cm/s to units of inches per minute
Answer:
220000 in/min
Explanation:
Step 1: Write out conversions
1 in ≈ 2.54 cm
60 sec = 1 min
Step 2: Set up dimensional analysis
[tex]\frac{933cm}{s} (\frac{60s}{1min} )(\frac{1in}{2.54cm} )[/tex]
Step 3: Evaluate
220039.4 in/min
Step 4: Sig figs
There are 3 sig figs
220039.4 in/min ≈ 220000 in/min
What does the 2+ mean??
Which of the following changes lead to a decrease in entropy?
a. mixing of pure gases
b. sugar dissolving in coffee
c. melting snow
d. the sublimation (vaporization) of dry ice (solid carbon dioxide)
e. halving the volume of a gas
Answer:
halving the volume of a gas
Explanation:
Entropy refers to the degree of disorderliness of a system. The greater the volume of a gas, the greater its entropy. The entropy of a system is directly proportional to its volume.
Hence a decrease in the volume of a gas leads to a decrease in its entropy. Ultimately, if the volume of a given mass of gas is halved, its entropy decreases according.
To obtain the number of meters from a distance measured in centimeters, you must
By the number
Answer:
Divide by 100
Explanation:
4. A solution contains 62.1 g of ethylene glycol dissolved in 250.0 g of H2O. Calculate the mass % of ethylene glycol
Answer:
Explanation:
% mass of Ethylene glycol =( mass of ethylene glycol/ mass of solution )x100%
= 62.1 g/ (62.1 + 250 ) x 100%
= 24.24%
Mass percentage is a term that represents the concentration, basically mass by mass percentage. It tells about the percentage of a component in a whole component. Therefore, the mass % of ethylene glycol is 24.24%.
What is percentage by mass?Mass percentage represents the the percentage of each element that is making a particular compound. Mass percentage does not have any unit as numerator and denominator contains the same unit.
Mathematically,
Percentage of mass = (component’s mass ÷ total mass) x 100%
% mass of Ethylene glycol =( mass of ethylene glycol/ mass of solution)x100%
% mass of Ethylene glycol = 62.1 g/ (62.1 + 250 ) x 100
= 24.24%
Therefore, the mass % of ethylene glycol is 24.24%.
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What is the best reason for the scientific community to accept a theory?
Answer:it’s a
Explanation:
Use the drop-down menus to identify the career that matches each description Helos employees and management negotiate: Oversees payment of employees Maintains employee records, such as contact information: Oversees the Human Resources department of a company.
Answer:
✔ Labor Relations Specialist
✔ Compensation and Benefits Manager
✔ Human Resources Assistant
✔ Human Resources Manager
B
D
A
C
Answer:
Helps employees and management negotiate:
✔ Labor Relations Specialist or B.)
Oversees payment of employees:
✔ Compensation and Benefits Manager or D.)
Maintains employee records, such as contact information:
✔ Human Resources Assistant or A.)
Oversees the Human Resources department of a company:
✔ Human Resources Manager or C.)
Which coupling method is sensitive to temperature changes?
Answer:
Direct coupling
Explanation:
Direct coupling is sensitive to changes that occurs in temperature. It is electrical energy transfer using physical contact through a medium that is conductive.
It is useful in the interconnection of 2 circuits. This kind of coupling method can be done by a wire, a resistor or through mettalic bonding.
I need help on this!!!!!
E
1
1 point
Which of the following is an elemental substance?
Select all the correct answers.
Mercury
2
Oxygen (O2)
3
Platinum
Chlorine (C12)
Carbon Dioxide (CO2)
Answer:
oxygen and Carbon dioxide
convert 5 liters into kiloliters
Answer:0.005
Explanation:kilo means 1000 do you divide 5 by 1000 and you get.005
Answer: 0.005 kilolitres
Explanation:
5 liters = 0.005 kilolitres
Why? Because liters - kilolitres: ÷ 1000
From a 2.875 g sample containing only iron, sand, and salt, 0.660 g of iron and 1.161 g of sand were separated and recovered. What was the percent of salt in the original sample
Answer:
36.66%
Explanation:
Step 1: Given data
Mass of iron: 0.660 gMass of sand: 1.161 gMass of the sample: 2.875 gMass of salt: ?Step 2: Calculate the mass of salt
The mass of the sample is equal to the sum of the masses of the components.
m(sample) = m(iron) + m(sand) + m(salt)
m(salt) = m(sample) - m(iron) - m(sand)
m(salt) = 2.875 g - 0.660 g - 1.161 g
m(salt) = 1.054 g
Step 3: Calculate the percent of salt in the sample
We will use the following expression.
%(salt) = m(salt) / m(sample) × 100%
%(salt) = 1.054 g / 2.875 g × 100% = 36.66%
The percent of salt in the original sample containing only iron, sand, and salt is 36.66%.
What is salt?Salt is a mineral made up of primarily sodium chloride.
Seawater contains a vast amount of salt.
Given,
The total mass of the sample is 2.875 g
Mass of iron is 0.660 g
Mass of sand is 1.161 g
Step 1: To find the mass of salt
The total mass of the sample = the sum of the masses of the compounds
m(sample) = m(iron) + m(sand) + m(salt)
2.875 g = 0.660 g + 1.161 g + m(salt)
m(salt) = 2.875 g - 0.660 g - 1.161 g
m(salt) = 1.054 g
Step 2: Calculate the percent of salt in the sample
[tex]\%(salt) = \dfrac{m(salt) }{m(sample)} \times 100\%\\\\\\\%(salt) = \dfrac{1.054 g }{2.875 g} \times 100\% = 36.66\%[/tex]
Thus, the percentage of salt in the sample is 36.66%.
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Which of the following is an extensive property? a. melting point b. hardness c. color d. volume e. temperature
The answer is d volume. This is because the melting point, color, temperature are all intensive properties. While hardness is neither extensive or intensive. Volume is the only one that is considered an extensive property.
I hope this helps ! <3
Answer: volume
explanation:
why is a lot of energy needed to break covalent bonds
Answer:
The strength of a bond between two atoms increases as the number of electron pairs in the bond increases.
Explanation:
what is formed when polyatomic ions bond with other ions.
A) ionic compounds.
B) neutral compounds.
C) ionic elements.
D) neutral elements.
Answer:
iconic compounds is your anwser
Answer:
Iconic Compounds
Explanation:
I watched a video about it.
Have a nice Friday!
A submarine took 9 hours to complete a journey. For the first 5 hours, it traveled at an average speed of 106km/h. For the rest of the journey, it traveled at an average speed of 125km/h. What was the total distance of the journey?
The correct answer is 1030 km
Explanation:
The distance a body such as a submarine travels depends on two main variables the time of the movement and the speed. Indeed, to calculate the distance it is possible to use the formula d = s x t. The process to calculate the distance of the submarine journey is shown below:
Distance in the first part of the journey:
It is known during the first part of the journey the submarine traveled 5 hours at a speed of 106 km/h
Distance = speed × time
D = 106 km/h × 5 h
D = 530 km
Distance in the second part of the journey:
During the remaining 4 hours (the first part took 5 hours and the total time traveled were 9 hours) the speed was 125km/h. Now, let's calculate the distance covered during this part of the journey
Distance = speed × time
D= 125 km/h × 4 h
D= 500 km
Total distance:
Finally, add both distances to know the total distance
530 km + 500 km = 1030 km
How are most meteoroids formed? A. As the Sun burns, it throws off small, solid particles at a regular rate which are launched into the Solar System. B. They are created in the explosions that occur when stars die and eventually reach the Solar System. C. They are small pieces that are left over from the formation of the Solar System. D. They are small pieces of debris that are the result of collisions of asteroids, comets, moons, and even planets within the Solar System. Will give brainlist
Answer:
It is no. D
Explanation:
Many meteoroids are formed from the collision of asteroids, which orbit the sun between the paths of Mars and Jupiter in a region called the asteroid belt.
Why do fireworks produce different colors
Two or more than two atoms with different physical or chemical properties can not combine together to form an element. Energy is the only factor that determines the color of light of fireworks.
What is element?Element generally consist of atoms or we can atoms combine to form element. Atoms of an element is always same, means all the properties of all atoms of one type of element is same.
Fireworks has many different types of element. When any element is given an energy. Then the process of excitation of electrons takes place from its outermost shells. Every element absorb characteristic wavelength of energy and releases light to the corresponding wavelength.
Therefore, energy is the only factor that determines the color of light of fireworks.
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Which charts or graphs always use axes both labeled with quantitative values and show individual points of data, meaning that each point matches with one value on the x-axis and one value on the y-axis? Check all that apply.
The graphs which use axes both labeled with quantitative values and show individual points of data include:
Scatter plotsLine graphsBar graphs.What is a Graph?Thus is defined as a pictorial representation of data or variables in an organized or definite manner.
The graphs mentioned above always have each point matching with one value on the x-axis and one value on the y-axis.
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How many atoms are represented by one formula unit of aluminum carbonate A12(CO2)3
Answer:
well ,if I have done my sum rights there are
14 atom in the one formula unit of aluminium carbonate.
Answer:
14 atoms
Explanation:
what is Corona virus And explain breifly in
Answer:
it is a viral disease . it is infected by one person to other .
Draw the product formed when 2-butanol undergoes reaction with TsCl and Et3N. CH3C6H4SO2Cl.
Answer:
Explanation:
In organic chemistry, the reaction between 2-butanol with TsCl and Et3N is known as the tosylation of the alcohol hydroxyl group. Alcohol is being changed to tosylate by the use of tosyl chloride under the influence of a base. Tosylation of alcohol is an example of a nucleophilic substitution reaction. From the image attached below, we will see how the reaction between 2-butanol proceed into the product by using tosyl chloride and a base(Et3N).
Which statement explains why carbon-14 dating cannot be used to date ancient rocks?
Carbon-14 decays at a varying rate.
Carbon-14 decays relatively quickly.
Carbon-14 can be used only to date the remains of organisms.
Carbon-14 has a half-life that is much longer than potassium.
Answer:
its, b
Explanation:
took the test on e2020
Carbon-14 dating cannot be used to date ancient rocks because:
B. Carbon-14 decays relatively quickly.
Carbon-14 dating:It is a method for tracking down the time of natural materials, like wood, in light of their substance of radioactive carbon. Also, it is a technique for estimating the time of natural matter by investigating its carbon content.
The decay takes place around 55,000 years i.e half the amount of the radioisotope present at any given time.
Thus, option B is correct.
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In run 1, you mix 7.9 mL of the 43 g/L MO solution (MO molar mass is 327.33 g/mol), 3.13 mL of the 0.040 M SnCl2 in 2.0 M HCl solution, 5.49 mL of 2.0 M HCl solution, and 3.43 mL of 2.0M NaCl solution. What is the [H3O+]? Remember that there is a contribution of H3O+ from two solutions.
Answer:
Concentration of H3O⁺ [H3O⁺] = 0.864 M
Explanation:
Given that:
The mass concentration of MO = 43 g/L
The volume of MO = 7.9 mL = 7.9 × 10⁻³ L
Recall that
The mass number of MO = Mass concentration of MO × Volume of MO
The mass number of MO = (43 g/L) * (7.9 × 10⁻³ L)
The mass number of MO = 0.3397 g
number of moles of MO = (mass number of MO) / (molar mass of MO)
number of moles of MO = (0.3397 g) / (327.33 g/mol)
moles of MO = 0.00104 mol
The total volume = 7.9 mL + 3.13 mL + 5.49 mL + 3.43 mL
The total volume = 19.95 mL = 19.95 × 10⁻³ L
Concentration of MO [MO} =(number of moles of MO) / (total volume)
[MO] = 0.00104 mol / 19.95 × 10⁻³ L
[MO] = 5.2130 × 10⁻⁸ M
the number of moles of H3O⁺ = molarity of HCl in the solution × the volume of HCl in solution
the number of moles of H3O⁺ = [(2.0 M) * (3.13 mL)] + [(2.0 M) * (5.49 mL)]
the number of moles of H3O⁺ = 17.24 mmol
Concentration of H3O⁺ [H3O⁺] = (the number of moles of H3O⁺) / (total volume)
Concentration of H3O⁺ [H3O⁺] = (17.24 mmol) / (19.95 mL)
Concentration of H3O⁺ [H3O⁺] = 0.864 M
The Concentration of H3O⁺ [H3O⁺] is 0.864 M
Calculation of the H3O⁺ concentration:But before that following calculations should be needed.
The mass number of MO = Mass concentration of MO × Volume of MO
= (43 g/L) * (7.9 × 10⁻³ L)
= 0.3397 g
Now
number of moles of MO = (mass number of MO) / (molar mass of MO)
= (0.3397 g) / (327.33 g/mol)
= 0.00104 mol
Now
The total volume = 7.9 mL + 3.13 mL + 5.49 mL + 3.43 mL
= 19.95 mL
= 19.95 × 10⁻³ L
Now
Concentration of MO [MO} =(number of moles of MO) / (total volume)
= 0.00104 mol / 19.95 × 10⁻³ L
5.2130 × 10⁻⁸ M
Now
the number of moles of H3O⁺ = molarity of HCl in the solution × the volume of HCl in solution
= [(2.0 M) * (3.13 mL)] + [(2.0 M) * (5.49 mL)]
= 17.24 mmol
Now
Concentration of H3O⁺ [H3O⁺] = (the number of moles of H3O⁺) / (total volume)
= (17.24 mmol) / (19.95 mL)
= 0.864 M
Hence, The Concentration of H3O⁺ [H3O⁺] is 0.864 M
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I am timed please help
Answer:
the substance is element.
because an element is pure substance which is made of only one kind of atom.
Observations made during an experiment are called
The particles in a gas have more space between them because
Answer:
They are more spread out.
Explanation:
The atoms and molecules in gases are much more spread out than in solids or liquids. They vibrate and move freely at high speeds. A gas will fill any container, but if the container is not sealed, the gas will escape. Gas can be compressed much more easily than a liquid or solid.
Answer:
Explanation:
Explanation:
Gas – In a gas, particles are in continual straight-line motion. The kinetic energy of the molecule is greater than the attractive force between them, thus they are much farther apart and move freely of each other. In most cases, there are essentially no attractive forces between particles
2. How do we identify bias and avoid thinking errors when evaluating online
information?
Answer:
We can identify bias and avoid thinking errors when evaluating online information when there is a certain degree of partiality in the way the information is given. The writer takes one side and doesn’t consider benefits of the other side/view.
We can identify bias and avoid thinking errors when evaluating online information by making our personal findings and research from other sources and then comparing the two.
2. The four parts, or blocks, on the
periodic table are _d, and f.
s, P
a, b
Answer:
s, p
Explanation:
The four parts, or orbitals, on the periodic table are s, p, d, and f.