Answer:
a. 122.6 mL / pH = 4.03
b. 193.6 mL / pH = 5.73
Explanation:
In the equivalence point we know: mmoles acid = mmoles base- And the pH in a titration between a weak base and a strong base, is acid, at the equivalence point. For the volume, we can replace the equation with the data given.
a. 0.125M . volume of acid = 65.5 mL . 0.234M
Volume of acid = (65.5 . 0.234) / 0.125 = 122.6 mL
Total volume at the equivalence point = 188.1 mL
b. 0.125M . volume of acid = 21.8 mL . 1.11 M
Volume of acid = (21.8 . 1.11) / 0.125 = 193.6 mL
Let's calculate the pH. In the equilavence point we have a neutralization reaction.
a. NH₃ + HCl → NH₄Cl
All the mmoles of protons (65.5 mL . 0.234M) react to ammonia, to obtain ammonium.
New concentration is: 15.32 mmoles / 188.1 mL = 0.0814 M
This is the [NH₄⁺] to determine the pH in the acid base equilibrium.
NH₄⁺ + H₂O ⇄ NH₃ + H₃O⁺ Ka
Expression for Ka = [NH₃] . [H₃O⁺] / [NH₄⁺]
5.6×10⁻¹⁰ = x² / (15.32 - x)
(We can avoid the quadratic equation 'cause Ka is so small)
√(5.6×10⁻¹⁰ . 15.32) = x → [H₃O⁺] = 9.26×10⁻⁵
pH = - log [H₃O⁺] → 4.03
b. CH₃NH₂ + HCl → CH₃NH₃Cl
All the mmoles of protons (21.8 mL . 1.11M) react to methylamine, to obtain methylammonium.
New concentration is: 24.2 mmoles / 193.6 mL = 0.125 M
This is the [CH₃NH₃⁺] to determine the pH in the acid base equilibrium.
CH₃NH₃⁺ + H₂O ⇄ CH₃NH₂ + H₃O⁺ Ka
Expression for Ka = [CH₃NH₂] . [H₃O⁺] / [CH₃NH₃⁺]
2.7×10⁻¹¹ = x² / (0.125 - x)
(We can avoid the quadratic equation 'cause Ka is so small)
√(2.7×10⁻¹¹ . 0.125) = x → [H₃O⁺] = 1.84×10⁻⁶
pH = - log [H₃O⁺] → 5.73
The pH of the equivalence point of 0.125M HCl with NH₃ is 4.03 and with CH₃NH₂ is 5.73.
What is equivalence point?In the acid - base titration, at the equivalence point equal moles of acid as well as of base are present.
First we calculate the volume of HCl by using the below equation as:
M₁V₁ = M₂V₂, whereM₁ = molarity of NH₃ = 0.234 M
V₁ = volume of NH₃ = 65.5 mL
M₂ = molarity of HCl = 0.125 M
V₂ = volume of HCl = ?
V₂ = (65.5 . 0.234) / 0.125 = 122.6 mL
Total volume at the equivalence point = 188.1 mL
Chemical reacion will be written as:
NH₃ + HCl → NH₄Cl
All moles of protons react with moles of ammonia, so new moles (n) will be calculated as:
n = molarity × volume
n = 65.5 mL × 0.234M = 15.32 moles
Now, concentration in terms of molarity will be 15.32 mmoles / 188.1 mL = 0.0814 M
pH in the acid-base reaction due to [NH₄⁺], as:
NH₄⁺ + H₂O ⇄ NH₃ + H₃O⁺
Value of Ka for this reaction is = 5.6×10⁻¹⁰
According to the ICE table, Ka equation will be written as-
5.6×10⁻¹⁰ = x² / (15.32 - x)
x = [H₃O⁺] = 9.26 × 10⁻⁵
pH = - log [H₃O⁺] = 4.03
Again we calculate the volume of HCl with the CH₃NH₂ as:0.125M . volume of acid = 21.8 mL . 1.11 M
Volume of acid = (21.8 . 1.11) / 0.125 = 193.6 mL
Total volume at the equivalence point = 215.4 mL
Chemical reacion will be written as:
CH₃NH₂ + HCl → CH₃NH₃Cl
All moles of protons react with moles of ammonia, so new moles (n) will be calculated as:
n = 21.8 mL . 1.11M = 24.2 moles
Now, concentration in terms of molarity will be 24.2 moles / 215.4 mL = 0.11M
pH in the acid-base reaction due to [CH₃NH₃⁺], as:
CH₃NH₃⁺ + H₂O ⇄ CH₃NH₂ + H₃O⁺
Value of Ka = 2.7×10⁻¹¹
According to the ICE table, Ka equation will be written as-
2.7×10⁻¹¹ = x² / (0.11 - x)
x = [H₃O⁺] = 5.4×10⁻⁶
pH = - log [H₃O⁺] = 5.73
Hence the value of pH will be 4.03 and 5.73 respectively.
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Calculate the number of hydrogen atoms in a sample of hydrazine . Be sure your answer has a unit symbol if necessary, and round it to significant digits.
Answer:
[tex]atoms \ H= 9.767x10^{24}atoms[/tex]
Explanation:
Hello!
In this case, considering that the mass of hydrazine is missing, we can assume it is 130.0 g (a problem found on ethernet). In such a way, since we need a mass-mole-atoms relationship by which we can compute moles of hydrazine given its molar mass (32.06 g/mol), then the moles of hydrogen considering one mole of hydrazine has four moles of hydrogen and one mole of hydrogen has 6.022x10²³ atoms (Avogadro's number); therefore, we proceed as shown below:
[tex]atoms \ H=130.0gN_2H_4*\frac{1molN_2H_4}{32.06gN_2H_4} *\frac{4molH}{1molN_2H_4} *\frac{6.022x10^{23}atoms}{1molH}\\\\atoms \ H= 9.767x10^{24}atoms[/tex]
Notice 130.0 g has four significant figures, therefore the result is displayed with four as well.
Best regards!
Fill in the Blank
Complete the following sentence. Remember to spell correctly.
The most common biomass is
which people have used to heat their homes for centuries.
Calculate the change in entropy when 10.0 g of CO2 isothermally expands from a volume of 6.15 L to 11.5 L. Assume that the gas behaves ideally.
Answer:
The change in entropy of the carbon dioxide is [tex]1.183\times 10^{-3}[/tex] kilojoules per Kelvin.
Explanation:
By assuming that carbon dioxide behaves ideally, the change in entropy ([tex]\Delta S[/tex]), measured in kilojoules per Kelvin, is defined by the following expression:
[tex]\Delta S = m\cdot \bar c_{v}\cdot \ln \frac{T_{f}}{T_{o}}+m\cdot \frac{R_{u}}{M}\cdot \ln \frac{V_{f}}{V_{o}}[/tex] (1)
Where:
[tex]m[/tex] - Mass of the gas, measured in kilograms.
[tex]\bar c_{v}[/tex] - Isochoric specific heat of the gas, measured in kilojoules per kilogram-Kelvin.
[tex]T_{o}[/tex], [tex]T_{f}[/tex] - Initial and final temperatures of the gas, measured in Kelvin.
[tex]V_{o}[/tex], [tex]V_{f}[/tex] - Initial and final volumes of the gas, measured in liters.
[tex]R_{u}[/tex] - Ideal gas constant, measured in kilopascal-cubic meter per kilomole-Kelvin.
[tex]M[/tex] - Molar mass, measured in kilograms per kilomole.
If we know that [tex]T_{o} = T_{f}[/tex], [tex]m = 0.010\,kg[/tex], [tex]R_{u} = 8.315\,\frac{kPa\cdot m^{3}}{kmol\cdot K}[/tex], [tex]M = 44.010\,\frac{kg}{kmol}[/tex], [tex]V_{o} = 6.15\,L[/tex] and [tex]V_{f} = 11.5\,L[/tex], then the change in entropy of the carbon dioxide is:
[tex]\Delta S = \left[\frac{ (0.010\,kg)\cdot \left(8.315\,\frac{kPa\cdot m^{3}}{kmol\cdot K} \right)}{44.010\,\frac{kg}{kmol} } \right]\cdot \ln \left(\frac{11.5\,L}{6.15\,L}\right)[/tex]
[tex]\Delta S = 1.183\times 10^{-3}\,\frac{kJ}{K}[/tex]
The change in entropy of the carbon dioxide is [tex]1.183\times 10^{-3}[/tex] kilojoules per Kelvin.
how is black oxide converted into red oxide
Answer:
The usual way of converting black oxide to red oxide involves treating the black oxide with sulphuric acid and then roasting the intermediate product thus formed. lt is known that the amount of acid can be considerably less than the stoichiometric amount needed to convert all the black oxide to a sulphate.
Hope it helps :9
In the electron dot diagram for sulfur monoxide, each atom of sulfur will have how many unshared pairs of electrons an each atom of oxygen will have how many unshared pairs of electrons.
Answer:
Both sulphur and oxygen have two unshared pairs of electrons
Explanation:
The compound sulphur monoxide has the formula S=O. It is quite analogous to the diatomic molecules of the group 16 elements.
We must remember that each group element has six electrons in their outermost shell. Two of these are lone pairs leaving only two electrons available for bond formation.
These two electrons are used to form the sigma and pi bonds in S=O, leaving two lone pairs on each of sulphur and oxygen atoms.
What do chemical compounds want to obey?
Answer:
Their atoms obey the octet rule
Explanation:
Chemical compounds are formed when atoms combine with one another in order to comply with the octet rule. The octet configuration gives an atom stability in electronic structure.
When atoms become isoelectronic with noble gases, it confers a special stability on them. Therefore, to attain this state, they gain or lose electron or share their electrons with other species.A solid substance was tested in the laboratory. The test results are listed below: 1.) dissolves in water 2.) is an electrolyte 3.) melts at a high temperature. Based on these results, the solid substance could be
Answer:
NaCl may be i guess so....
Calculate the number of S atoms in 0.670 mole of S.
Answer:
4.03 × 10²³ atomsExplanation:
The number of S atoms can be found by using the formula
N = n × Lwhere n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
N = 0.67 × 6.02 × 10²³
We have the final answer as
4.03 × 10²³ atomsHope this helps you
A runner wants to run 10.4 km k m . She knows that her running pace is 8.0 mi/h m i / h .
Answer:
Approximately 49 minutes.
Explanation:
1 mile = 1.6 km
So 8.0 x 1.6 km
Minutes required: [tex]\frac{10.4 times 60 }{8.0 times 1.6}[/tex]= 48.75 minutes
I hope this helped :)
What is the correct electron configuration for an element with 5 electrons in
the 3d energy sublevel?
Answer:
[tex]1s^2,2s^2,2p^6,3s^2,3p^6,4s^2,3d^5[/tex]
Explanation:
Hello!
In this case, since electron configurations allows to understand how the electrons in an atoms are arranged depending on the energy levels from 1 to 7 and subshells s, p d and f, considering the attached picture, if we want an element for which the last term in its electrons configuration was 3d⁵, we write:
[tex]1s^2,2s^2,2p^6,3s^2,3p^6,4s^2,3d^5[/tex]
It means that the element has 25 electrons, therefore, it should be manganese.
Best regards!
Answer: it's A the same answer as the dude above me not trying to type all that
Explanation: took the test for ap
What happens to gas particles when they are compressed?
1)Gas molecules move further apart.
2)Gas molecules get closer together.
3)Some gas molecules move further apart and some move closer together.
Answer:
3)Some gas molecules move further apart and some move closer together.
Explanation:
because When more gas particles enter a container, there is less space for the particles to spread out, and they become compressed. The particles exert more force on the interior volume of the container. This force is called pressure. There are several units used to express pressure.
What would the molecular formula be if potassium and chlorine reacted to form a neutral compound?
compound is formed when potassium reacts with chlorine, which forms ions with a negative charge. The formula of this compound would therefore be KCl.
The molecular formula if potassium and chlorine reacted to form a neutral compound will be KCI.
What happens to potassium if it reacts to chlorine?Potassium metal, K, will burn in the presence of chlorine gas,[tex]Cl_{2}[/tex], to form potassium chloride, KCl, an ionic compound.The chemical equation of this is [tex]2K_{aq}[/tex] + [tex]Cl_{2}[/tex]g→[tex]2KCL_{s}[/tex]We can also picture this reaction as being a redox reaction.When potassium metal is oxidized by chlorine gas to potassium cations, chlorine gas will be reduced to chlorine anions.The potassium cations and the chlorine anions will be combined to produce potassium chloride.To learn about potassium and chlorine reactions, refer to: https://brainly.com/question/20690183
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1 What is the total number of valence electrons in the Lewis structure of C104?
electrons
2 Draw a Lewis structure for CI04:
why is there not a corresponding drop in ionization energies between Bi and Po in the sixth period as N and O?
and why is there not a corresponding drop between Ba and Tl is the sixth period even though they are in the same group as Be and B?
Answer:
See explanation
Explanation:
According to the Journal of Chemical Education, Volume 80, No.8 (2003); "The first ionization energy of bismuth appears to be anomalous......It has been claimed that spin– orbit coupling by the Russell–Saunders scheme would lower the ground state of Bi+ ..."
However, the involvement of d and f orbitals in Bi and Po implies that the outermost orbitals are poorly screened hence the drop between nitrogen and oxygen is not observed between Bi and Po.
The same argument could be extended to explain the reason why there not a corresponding drop between Ba and Tl is the sixth period even though they are in the same group as Be and B.
What’s the order can someone help?
Where do karst regions occur?
Answer:
Image result for Where do karst regions occur?
Karsts are found in widely scattered sections of the world, including the Causses of France; the Kwangsi area of China; the Yucatán Peninsula; and the Middle West, Kentucky, and Florida in the United States.
Explanation:
Answer:
Middle West Kentucky.
Explanation:
Karst are found in widely scatter sections of the world.
is pasta and water magnetism, state of matter, or solubility?
please helpp!!
Answer:
solubility
Explanation:
The hybrid orbital set used by the central atom in no3- is_____ and why?
a. sp
b. sp3
c. SP2
d. sp3d2
e. sp3d
Answer:
c. SP2
Explanation:
The image in the diagram below shows the structure of NO₃⁻
Nitrogen is the central atom with the electronic configuration of 1s² 2s² 2p³.
So in its outermost shell, it has 3 electrons and the hybridization is sp²
However,
According to Hund's rule:
The ground state of Nitrogen is;
1s² 2s² 2p³
↑↓ ↑ ↑ ↑ ↑
At the excited state when it is attached to 3 different oxygen ions, we have:
1s² 2s² 2p⁵
O⁻ ---> ↑↓ ↑↓ ↑↓ ↑↓ ↑
1s² 2s² 2p⁵
O⁻ ---> ↑↓ ↑↓ ↑↓ ↑↓ ↑
1s² 2s² 2p⁴
O⁻ ---> ↑↓ ↑↓ ↑↓ ↑ ↑
Thus, the 3 sp² orbital lies in a plane and form 3 N - O σ- bond and one π- bond.
Which of these is NOT evidence that a chemical change has taken place?
temperature rising when 2 substances are mixed
gas production
color change
melting
Which trophic level has the most calorie count
Answer:
producer
Explanation:
The trophic level with the most calorie count is the producer.
A trophic level is a hierarchical level of the food chain with each level consisting of organisms that share the same feeding role in the ecosystem. A typical trophic level consists of the producers which occupy the base level, the primary, secondary, tertiary consumers respectively, and the decomposers.
The highest amount of energy exists at the base of the trophic level and decreases as we move up the trophic level, forming a kind of pyramid at the end. The producers have the highest amount of energy by directly converting energy from the sun to chemical energy. The consumers at subsequent levels are only able to utilize only about 10% of the chemical energy in their own foods.
A reaction has a theoretical yield of 124.3 g SF6, but only 113.7 g SF6 are obtained in the lab, what is the percent yield of SF6 for this reaction?
Answer:
Percent yield = 91%
Explanation:
Given data:
Theoretical yield of SF₆ = 124.3 G
Actual yield of SF₆ = 113.7 g
Percent yield of SF₆ = ?
Solution:
Formula:
Percent yield = (actual yield / theoretical yield)× 100
By putting values,
Percent yield = (113.7 g/ 124.3 g) × 100
Percent yield = 0.91 × 100
Percent yield = 91%
A carbocation is an example of a(an) ____. Does a carbocation accept a pair of electrons, or does it donate a pair of electrons?
A. Electrophile. The carbocation accepts a pair of electrons.
B. Nucleophile. The carbocation accepts a pair of electrons.
C. Electrophile. The carbocation donates a pair of electrons.
D. Nucleophile. The carbocation donates a pair of electrons.
Answer:
Option A. The carbocation accepts a pair of electrons.
Explanation:
A carbocation is defined as a positively charged carbon, which is bound to 3 substituents. Since it has no electrons nonbonding, it only has six electrons in its valence shell. With only six electrons in its valence shell, a carbocation is a powerful electrophile (and Lewis acid) and can react with any nucleophile that is found.
Carbocations are proposed as intermediates in many organic reactions. They also work like free radicals, which are electron-deficient species.
Same as free radicals, the carbocations are stabilized by alkyl substituents.
how many moles of NaCl are dissolved in 250 mL of solution if the solution concentration is 0.150 M?
Answer: ?L=250 mL × 1L =0.25L 1000 mL
0.150 M = moles of solute moles of solute = 0.038 mol.
Explanation:
what is the number of each element and the total number of atoms for vinegar?
determine moles of 1.5g of sodium carbonate.
Answer:
0.014mol
Explanation:
Given parameters:
Mass of Na₂CO₃ = 1.5g
Unknown:
Number of moles = ?
Solution:
Number of moles of a compound is mathematically expressed as;
Number of moles = [tex]\frac{mass}{molar mass}[/tex]
Molar mass of Na₂CO₃ = 2(23) + 12 + 3(16) = 106g/mol
Number of moles = [tex]\frac{1.5}{106}[/tex] = 0.014mol
The complete combustion of C4H10, will require how many moles of oxygen, O2? ________.
Answer:
2
Explanation:
C⁴H¹⁰ + 2O² —> 4CH²O + H²
element is responsible for the color of light produced.
13
In a flame test, the
a Non-metal
b. Metal
c. Halogen
d. Noble Gas
1. Use the table to
Answer: d
Explanation:because it makes sence i think
Determine the molecular geometry for ClF3ClF3.
a. seesaw
b. trigonal bipyramidal
c. square pyramidal
d. octahedral
Answer:
The correct option is b
Explanation:
Firstly, the compound is ClF₃ and not ClF₃ClF₃. The name of the compound ClF₃ is chlorine trifluoride. It's electron geometry is trigonal bipyramidal (with the chlorine at the center and the atoms of the fluorine forming a triangular bipyramid around it) with a bond angle of 175° with an hybridization of sp³d.
the eye is a substance of which major body system
Answer:
the visual system would be the answer
At what power of ten are we able to view the entire Earth in space?
Answer:
If I remember correctly it should be 10^7 meters.
Explanation:
The power of ten are we able to view the entire Earth in space is 10^8. This is further explained below.
What power of ten are we able to view the entire Earth in space?Generally, A telescope is simply defined as a device that magnifies views of faraway things
In conclusion, The power of the telescope will be at 10^8.
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