Answer:
to find out how somethings work
Explanation:
Answer:
Doing experiments is good because when you try these possibilities you can learn about something that you've tried or see why this experiment didn't really work. It also helps you understand that not everything you try will work. that's why we experiment.
Explanation:
Hope this helps:)
How many lbs are in 5 kilograms ?
Answer:
11.023 pounds
Explanation:
Which type of reaction has the general formula of AB + CD → AD + CB?
synthesis
decomposition
oxidation
replacement
Answer:
The answer is D. Replacement
The given reaction has been the symbolization for replacement reaction. Thus, option D is correct.
The given general reaction has been:
[tex]\rm AB\;+\;CD\;\rightarrow\;AD\;+\;CB[/tex]
In the given reaction, there has presence of compound AB and CD. The reaction between the two results in the formulation of AD and CB. In the reaction, the B has been more attracted by C and forms bond with C by replacing D.
In the same way, A has been more attracted with D and forms bond with D replacing C.
The type of reaction in which the more reactive element replaces the less reactive element has been termed as replacement reaction. Thus, the given reaction has been the symbolization for replacement reaction. Thus, option D is correct.
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Which property of a substance can be determined using a pH indicator?
A. acldity
B. bolling polint
C. density
D. electrical conductivity
E. thermal conductivity
Answer:
the correct answer would be A. acidity
Answer:
The answer is A.) Acidity
Using Gizmo ,describe the main use for each fuel Coal: Petroleum: In each case, what is the end product of burning the fossil fuel,and where does it go? Help is for today
Answer:
See explanation
Explanation:
Coal is primarily used for electricity generation. The burning of coal leads to emission of gases such as oxides of carbon, oxides of sulphur, oxides of nitrogen and water vapour. All these go straight into the atmosphere.
Petroleum is primarily used as transportation fuels. The burning of petroleum oils mostly leads to the emission of oxides of carbon and sulphur together with water vapour into the atmosphere.
Which question must be answered to complete the table below?
A 3-column table with 3 rows. Column 1 is labeled alpha decay with entries alpha particles, plus 2 and low. Column 2 is labeled Beta Decay with entries no entry, electron negative 1 positron positive 1, and medium. Column 3 is labeled Gamma decay with entries gamma rays, 0 and high.
a. What kind of shielding will block beta decay?
b. What is the penetrating power of beta decay?
c. What kind of particles are produced by beta decay?
d. How massive are the particles in beta decay?
Answer:
c
Explanation:
Which of the following reactions would you expect to produce the most energy?
A. Nuclear fusion of two hydrogen isotopes.
B. Combustion of hydrogen gas.
C. Combination of a strong acid and a strong base.
D. Burning a large hydrocarbon, such as oil.
Answer:
A
Explanation:
Nuclear fusion is a much more powerful reaction than any of the others.
Nuclear fusion of two hydrogen isotopes would expect to produce the most energy. Therefore, option (A) is correct.
What is nuclear fusion?Nuclear fusion can be defined as when two or more nuclei fuse together to form a single heavier nucleus. In this reaction, the matter is generally not conserved due to some of the mass of the nuclei being converted to energy.
For nuclear fusion, the nuclei must be brought closer to the reaction occurring. Each star in the universe, including sun, is shining due to nuclear fusion reactions. They produce large amounts of energy in this process.
In the Sun's core, hydrogen nuclei are get transformed into helium nuclei which are known as nuclear fusion. It takes place when four hydrogen nuclei fuse into each helium nucleus. During the Nuclear fusion process, some of the mass of hydrogen nuclei is transformed into energy.
Therefore, nuclear fusion is where hydrogen atoms combined to form helium to produce the most energy.
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When 60 mL of 0.22 M NH4Cl is added to 60 mL of 0.22 M NH3, relative to the pH of the 0.10 M NH3 solution the pH of the resulting solution will:____________.
Answer:
Will be more acidic
Explanation:
The equilibrium of NH3 in water is:
NH3(aq) + H2O(l) ⇄ NH4⁺(aq) + OH⁻(aq).
Where equilibrium constant, Kb, is:
Kb = 1.85x10⁻⁵ = [NH4⁺] [OH⁻] / [NH3]
From 0.10M NH3, the reaction will produce X of NH4⁺ and X of OH⁻ and Kb will be:
1.85x10⁻⁵ = [X] [X] / [0.10M]
1.8x10⁻⁶ = X²
X = 1.34x10⁻³ = [OH⁻]
As pOH = -log[OH⁻] = 2.87
And as pH = 14 - pOH
pH of the 0.10M NH3 is 11.13
Now, to find the pH of the NH4Cl and NH3 we need to use H-H equation for bases:
pOH = pKb + log [NH4⁺] / [NH3]
Where pKb is -log Kb = 4.74 and [] are moles of both compounds.
Moles of [NH4⁺] = [NH3] = 60mL, 0.060L*0.22M = 0.0132moles:
pOH = 4.74 + log [0.0132] / [0.0132]
pOH = 4.74
pH = 14 - 4.74 = 9.26
That means the pH of the resulting solution will be more acidic
Assuming that a cheese sandwich consists of 2 slices of bread and 3 slices of cheese, determine the number of whole cheese sandwiches that can be prepared from 44 slices of bread and 63 slices of cheese.
Answer:
21 is the max but with the bread ypu could make 22 if you had 3 more cheese
Enough of a monoprotic weak acid is dissolved in water to produce a 0.0129 M solution. The pH of the resulting solution is 2.65 . Calculate the Ka for the acid.
Answer:
Ka = 4.70x10⁻⁴M
Explanation:
The general dissociation of a weak acid, HX, is:
HX(aq) ⇄ H⁺(aq) + X⁻(aq)
And Ka is written as:
Ka = [H⁺] [X⁻] / [HX]
Where [] represents the molar concentration in equilibrium of each specie.
The equilibrium is reached when X of HX is dissociate in X H⁺ and X X⁻, that is:
[HX] = 0.0129M - X
[H⁺] = X
[X⁻] = X
As pH = -log [H⁺]:
10^-pH = [H⁺] = X = 2.239x10⁻³M
Solving:
[HX] = 0.0129M - 2.239x10⁻³M = 0.01066M
[H⁺] = 2.239x10⁻³M
[X⁻] = 2.239x10⁻³M
Ka = [H⁺] [X⁻] / [HX]
Ka = [2.239x10⁻³M] [2.239x10⁻³M] / [0.01066M]
Ka = 4.70x10⁻⁴M
The # of electrons in S2- -34 is
Answer:
The answer is 16
Explanation:
Sodium is located above potassium in Group 1 of the periodic table. If a potassium ion has a charge of +1, what is the charge on a sodium ion?
A. -1
B 0
C. +1
D +2
Answer:
C
Explanation:
It will be the same. That's what moving down a column means. The properties are going to be quite similar.
Calculate the mass of dinitrogen tetroxide(N2O4) that contains a billion oxygen atoms. Be sure your answer has a unit symbol if necessary, and round it to significant digits.
Answer:
23 * 10^ 9 atoms of oxygen
Explanation:
From the molecular formula of dinitrogen tetraoxide;
molar mass of dinitrogen tetraoxide = 92 g/mol
hence;
92 g of dinitrogen tetraoxide contains 4 atoms of oxygen
x g of dinitrogen tetraoxide will contain 1 * 10^ 9 atoms of oxygen
x = 92 * 1 * 10^ 9/4
x =23 * 10^ 9 atoms of oxygen
Calculate the freezing point of a solution containing 10 grams of KCl and 1100.0 grams of water. The molal freezing point depression constant (Kf) for water is 1.86
Answer:
- 0.454 °C
Explanation:
From the given information:
The mass of KCl = 10 grams
The molar mass of KCl = 74.55 g/mol
The molality can be calculated as:
[tex]Molality \ m = \dfrac{mass \ of \ KCl \times 1000}{molar \ mass \ of \ KCl \times 1100.0}[/tex]
[tex]Molality \ m = \dfrac{10 \ g \times 1000}{74.55 \ g/mol \times 1100.0}[/tex]
Molality m = 0.1219 M
For freezing point depression;
[tex]\Delta T_R = i \times k_f \times m[/tex]
The van't Hoff's Factor (i) for KCl = 2
The molar depression of freezing point constant [tex]k_f[/tex] = 1.86° C/m
∴
[tex]\Delta T_R = 2 \times 1.86 \times 0.1219[/tex]
[tex]\mathbf{\Delta T_R = 0.454^0\ C }[/tex]
However, the freezing point of water is known to be = 0°C
Therefore, the freezing point of the solution
= 0 °C - 0.454 °C
= - 0.454 °C
What is an extremophile? What domain is known for these organisms?
Extremophiles are bacteria, archaea, as well as eukarya across all three domains of life. Cells make up every organisms.
What is Extremophiles?Extremophiles contain bacteria, archaea, as well as eukarya from all three domains of life.
What is organisms ?Any organic, biological system which works as a separate entity was referred to as an organism.
Extremophiles are organisms that can survive in harsh settings, such as those with high temperatures, radiation, salt, or pH levels. In the planet's evolutionary development, several creatures have been ecologically dominating.
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Sam washed his favorite pair of jeans. He hung the wet jeans on a clothesline outside. An hour later the jeans were dry.
Which answer best describes that happened to the water that was in the wet jeans an hour later?
State your answer and provide an explanation for your answer
A It soaked into the ground.
B It disappeared and no longer exists.
C It is in the air in an invisible form.
D It moved up to the clouds.
E It chemically changed into a new substance.
F It went up to the Sun.
G It broke down into atoms of hydrogen and oxygen.
Please help D:
Answer:
THe sun evapored the water and the wind helped dry it to.
Explanation:
Lamark goes to a bowling alley to test his belief that rolling a bowling ball slowly will result in knocking down more pins. He gently rolls his bowling ball towards the bowling pins lined up at the end of the lane. The bowling ball stops in the middle of the lane without striking the pins. Which statement below best explains what happened?
Answer:
The ball's kinetic energy is transforming to potential energy.
Explanation:
the ball is stopping resulting in potential energy
Sulfur dioxide and oxygen react to form sulfur trioxide during one of the key steps in sulfuric acid synthesis. An industrial chemist studying this reaction fills a 50.0L tank with 14. mol of sulfur dioxide gas and 2.6 mol of oxygen gas, and when the mixture has come to equilibrium measures the amount of sulfur trioxide gas to be 1.6 mol. Calculate the concentration equilibrium constant for the reaction of sulfur dioxide and oxygen at the final temperature of the mixture. Round your answer to 2 significant digits.
Answer:
Explanation:
From the given information:
The equation for the reaction can be represented as:
[tex]2SO_2 + O_2 \to 2SO_3[/tex]
The I.C.E table can be represented as:
2SO₂ O₂ 2SO₃
Initial: 14 2.6 0
Change: -2x -x +2x
Equilibrium: 14 - 2x 2.6 - x 2x
However, Since the amount of sulfur trioxide gas to be 1.6 mol.
SO₃ = 2x,
then x = 1.6/2
x = 0.8 mol
For 2SO₂; we have 14 - 2x
= 14 - 2(0.8)
= 14 - 1.6
= 12.4 mol
For O₂; we have 2.6 - x
= 2.6 - 1.6
= 1.0 mol
Thus;
[SO₂] = moles / volume = ( 12.4/50) = 0.248 M ,
[O₂] = 1/50 = 0.02 M ,
[SO₃] = 1.6/50 = 0.032 M
Kc = [SO₃]² / [SO₂]² [O₂]
= ( 0.032²) / ( 0.248² x 0.02)
= 0.8325
Recall that; the equilibrium constant for the reaction [tex]2SO_2 + O_2 \to 2SO_3[/tex] = 0.8325;
If we want to find:
[tex]SO_2 + \dfrac{1}{2}O_2 \to SO_3[/tex]
Then:
[tex]K_c = (0.8325)^{1/2}[/tex]
[tex]\mathbf{K_c = 0.912}[/tex]
Since no temperature is given to use in the question, it will be impossible to find the final temperature of the mixture.
OMG plz help me out with this!!
What are 3 differences between animal cells and plant cells?
What do the cell wall and chloroplasts do for the plant cell?
What are 2 things that animal cells and plant cells have in common?
Thank you!
I NEED HELP ASAP
Types of Cells
1) I have a cell membrane?
PROKARYOTE
EUKARYOTE *******
BOTH
2)I have a nucleus *
PROKARYOTE*****
EUKARYOTE
BOTH
3)I am a bacteria *
PROKARYOTE
EUKARYOTE
BOTH
1) Both cells have a cell membrane.
2) A nucleus is present in only Eukaryote cells.
3) I'm pretty sure Prokaryote cells are bacteria.
Hope this helps!! :)
Which of the following represents the equation for volume?
L x H
L x W
L x W x H
W x H
Answer:
L× W×H
Please mark me as brainlist.Answer:
The correct answer is L x W x H :)
What is the mass number of an element?
A. Mass number is the number of protons in the nucleus.
B. Mass number is the mass of the protons in the nucleus.
C. Mass number is the mass of the most abundant isotope.
D. Mass number is the atomic mass of a particular isotope.
The mass number of an element is the sum of the protons and neutrons present in the nucleus of the atoms of the element.
What is mass number?The mass number of an element is the number obtained when the number of protons and neutrons in the nucleus of an atom of the element are summed together.
The sum of protons and neutrons in the nucleus of an atom is collectively known as the nucleon. Thus, the mass number of an atom can also be referred to as the nucleon of the atom.
This can be mathematically expressed as:
Mass number = number of protons + number of neutrons.
Atoms generally contain protons, neutrons, and electrons. The protons are positively charged and are located in the nucleus, the neutrons are also located in the neucleus but have no charges. The electrons, on the other hand, are located outside the nucleus in regions referred to as orbitals.
The sum of the protons and neutrons determine the mass of an atom because the contribution of electrons to the mass of atoms is negligible.
Thus, the mass number of an element is the sum of proton and neutron numbers present in the nucleus of the atoms of the element.
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What happens when the sound waves released by a bat hit an object?
O The sound waves are diffused.
O The sound waves are reflected.
O The sound waves are refracted.
O The sound waves are absorbed.
Answer:
O The sound waves are reflected.
Explanation:
When sound waves released by a bat hits an object, the sound waves are reflected back.
Bats used sound reflection for echolocation to determine the position of nearby objects.
Also, they use it to determine the shape and size of objects.
The mechanism where bats use sound to determine location is known as echolocation. The bat picks up the reflected sound and projects the location of their targets.Answer:
B
The sound waves are reflected.
Explanation:
Calculate the number of moles of barium chloride in 427g of a 3.17%by mass barium chloride solution?a) 6.5x10^02molb) 7.83x10^02molc) 4.31x10^02mold) 7.81x10^02mole) 4.27x10^02mol
Answer:
The answer is "Option a".
Explanation:
Multiply the mass of the solutions by 3.17% to get the mass of [tex]BaCl_2[/tex]:
[tex]\to 427 \ g \times 0.0317 = 13.56\ g[/tex]
Divide this mass with BaCl2's molecular concentration to acquire the mole ratio:
[tex]molar mass = 208.24 \frac{g}{mol}\\\\moles = \frac{13.56}{208.24} = 0.065 \ moles \\\\[/tex]
[tex]= 6.5 \times 10^{-2} \ moles[/tex]
A 427 g sample is 3.17% by mass barium chloride contains 6.5 × 10⁻² moles of BaCl₂.
A 427 g sample is 3.17% by mass barium chloride, that is, there are 3.17 g of barium chloride per 100 g of sample.
The mass of barium chloride in 427 g of the sample is:
[tex]427gSample \times \frac{3.17gBaCl_2}{100gSample} = 13.5gBaCl_2[/tex]
We can calculate the number of moles in 13.5 g of barium chloride using its molar mass (208.23 g/mol).
[tex]13.5 g \times \frac{1mol}{208.23g} = 6.5 \times 10^{-2} mol[/tex]
A 427 g sample is 3.17% by mass barium chloride contains 6.5 × 10⁻² moles of BaCl₂.
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The distribution coefficient between methylene chloride and water for solute Y is 14. An amount of 72.0 g of Y is dissolved in 180 mL of water. a) What weight of Y would be removed from water with a single extraction with 180-mL of methylene chloride? Report to 1 decimal place. b) What total weight of Y would be removed from water (the original solution) with two successive extractions with 90-mL portions each of methylene chloride?
Answer:
a)Weight of Y extracted from water in single extraction = 67.2 g
b) Total weight of Y extracted from water in two successive extractions = 70.9 g
Explanation:
Distribution coefficient, Kd = Cs / Cm
where Cs is concentration of solute in methylene chloride; Cm is concentration of solute in water
a) Let x g of solute Y be extracted into methylene chloride
72.0 - x g of Y will be left in water
Kd = (x/180 mL of methylene chloride) / (72.0 - x/180 mL of water) = 14
14 = 180 * x / 180 * 72.0 - x
x = 14(72.0 - x)
x = 1008 - 14x
15x = 1008
x = 1008/15
x = 67.2 g
Weight of Y extracted from water in single extraction = 67.2 g
b) First extraction: Let x g of solute Y be extracted into methylene chloride
72.0 - x g of Y will be left in water
14 = x/90 / 72.0 - x/180
14 = 180x/ 90(72.0 - x)
14 = 2x/ 72.0 - x
2x = 14(72.0 - x)
2x = 1008 - 14x
16x = 1008
x = 63.0 g
Second extraction: Amount of solute left in water after first extraction = 72 - 63 = 9.0 g
Let x g of solute Y be extracted into methylene chloride
9.0 - x g of Y will be left in water
14 = x/90 / 9.0 - x/180
14 = 180x/ 90(9.0 - x)
14 = 2x/ 9.0 - x
2x = 14(9.0 - x)
2x = 126 - 14x
16x = 126
x = 7.90 g
Total weight of Y extracted = (63 + 7.90) g
Total weight of Y extracted from water in two successive extractions = 70.9 g
a) The Weight of Y extracted from water in single extraction is 67.2 g
b) The Total weight of Y extracted from water in two successive extractions should be 70.9 g
Calculation of weight:Here
The distribution coefficient, Kd should be
= Cs / Cm
where
Cs should be a concentration of solute in methylene chloride;
Cm should be a concentration of solute in water
a) Let us assume x g of solute Y that should be extracted into methylene chloride
So,
72.0 - x g of Y will be left in water
And, now
Kd = (x/180 mL of methylene chloride) / (72.0 - x/180 mL of water) = 14
So,
14 = 180 * x / 180 * 72.0 - x
x = 14(72.0 - x)
x = 1008 - 14x
15x = 1008
x = 1008/15
x = 67.2 g
b)
Now First extraction:
Let x g of solute Y be extracted into methylene chloride
So,
72.0 - x g of Y will be left in water
14 = x/90 / 72.0 - x/180
14 = 180x/ 90(72.0 - x)
14 = 2x/ 72.0 - x
2x = 14(72.0 - x)
2x = 1008 - 14x
16x = 1008
x = 63.0 g
Second extraction:
Amount of solute left in the water after the first extraction that should be
= 72 - 63
= 9.0 g
Now
Let x g of solute Y be extracted into methylene chloride
9.0 - x g of Y will be left in water
14 = x/90 / 9.0 - x/180
14 = 180x/ 90(9.0 - x)
14 = 2x/ 9.0 - x
2x = 14(9.0 - x)
2x = 126 - 14x
16x = 126
x = 7.90 g
Total weight of Y extracted = (63 + 7.90) g
= 70.9g
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Define dynamic equilibrium.
a) no reactants react no products are formed the rate of the forward reaction
b) is faster than the rate of the reverse reaction the rate of the reverse reaction
c) is faster than the rate of the forward reaction the rate of the forward reaction
d) equals the rate of the reverse reaction
Answer:
d) The rate of forward reaction equals the rate of the reverse reaction
Explanation:
A dynamic equilibrium is attained when the rate of forward reaction is the same as reverse reaction. It occurs majorly in a reversible reaction. Thus, no change occurs in the reaction.
The process can be control by the immediate removal of the product as it is formed. This ensure that the reaction stops when all reactants are used up.
A bomb calorimeter with a heat capacity of 837 J∘C contains 745 g of water. It burns 2.50 g C8H18 resulting in the temperature going from 15.0∘C to 33.8∘C. What is the value of the heat transferred (in kilojoules) by the reaction from the perspective of the system?
Answer:
74.3kJ are transeferred
Explanation:
In the bomb calorimeter, the burning of C₈H₁₈ is producing heat that is been absorbed for the calorimeter and the water.
Heat absorbed calorimeter:
837J/°C * (33.8°C-15.0°C) = 15735.6J
Heat absorbed water:
C*m*ΔT
C specific heat of water (4.184J/g°C), m is mass of water (745g), and ΔT change in temperature (33.8°C - 15°C = 18.8°C)
4.184J/g°C*745g*18.8°C = 58601.1J
Heat released by the reaction:
15735.6J + 58601.1J = 74336.7J
74.3kJ are transeferred
It is critical to watch or _________________ what is happening with every step of your experiment
It is critical to watch or observe what is happening with every step of your experiment
Suppose a student needs to standardize a sodium thiosulfate, Na2S2O3,Na2S2O3, solution for a titration experiment. To do so, he or she will react it with a solution of iodine. The student adds a 1.00 mL1.00 mL aliquot of 0.0200 M KIO30.0200 M KIO3 solution to a flask, followed by 3 mL3 mL of distilled water, 0.2 g0.2 g of solid KI,KI, and 1 mL H2SO4.1 mL H2SO4. The student then titrates the solution with sodium thiosulfate solution in order to determine the exact concentration of Na2S2O3.Na2S2O3. The end point of the titration is reached after 0.90 mL0.90 mL of Na2S2O3Na2S2O3 is dispensed from a microburet. What is the concentration of the standard sodium thiosulfate solution?
Answer:
0.133
Explanation:
reaction between KIO3 and KI in acidic medium
IO3⁻ +5I⁻ +6h⁺ → 3I₂ + 3H₂O
I₂ reacts with thiosulphate
NaS₂O₃ → 2Na⁺ + S₂O₃²⁻
net reaction
IO⁻₃ + 6H⁺ + 6S₂O₃³⁻ → I⁻ + 3S₄O₆²⁻ + 3H₂O
mole of KIO₃
= molarity x volume
[tex]\frac{0.02mol}{L} *0.01L[/tex]
= 0.00002mol
a mole of KIO₃ has reaction with 6 mol of S₂O₃²⁻
= 2x6x10⁻⁵
= 0.00012 mol
volume = 0.90 ml
1 ml = 0.001L
0.90ML = 0.0009L
to get concentration,
molarity/volume
= 0.00012/0.0009
= 0.133m
The concentration of the standard sodium thiosulfate solution is ; 0.133
The net chemical reaction equation
IO₃⁻ + 6H⁺ + 6S₂O₃³⁻ ----> I⁻ + 3S₄O₆²⁻ + 3H₂O
First step : Determine the moles of KIO₃
number of moles = molarity * volume
= 0.02 mol / L * 0.01 L
= 0.00002 mol
From the net chemical reaction equation
one ( 1 ) mole of KIO₃ reacts with 6 moles of S₂O₃²⁻
∴ number of moles in the reaction = 6 * 0.00002 = 0.00012 mol.
Final step : Determine the concentration of sodium thiosulfate solution
Given Volume = 0.90 ml = 0.0009 L
∴ concentration of sodium thiosulfate solution
= 0.00012 / 0.0009 = 0.133
Hence we can conclude that The concentration of the standard sodium thiosulfate solution is ; 0.133
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Please select the word from the list that best fits the definition
Represents a range of responses to a question:
Caption
Legend/Key
Scale
Answer:
The answer is B(scale)
Explanation:
Since the question asked about a range, the scale would be the most logical answer since scales are used to measure.
Answer:
the answer is C.
Explanation:
What quantity (moles) of NaOH must be added to 1.0 L of 1.8 M HC2H3O2 to produce a solution buffered at pH
Answer:
a) What quantity (moles) of NaOH must be added to 1.0 L of 1.8 M HC2H3O2 to produce a solution buffered at pH = pKa?
Step 1: Data given
Volume of HC2H3O2 = 1.0 L
Molarity of HC2H3O2 = 1.8 M
Ka = 1.8*10^-5
ph = pK = -log(1.8*10^-5) = 4.74
Step 2:
Use the Henderson-Hasselbalch equation.
pH = pKa + log(A-/HA)
4.74 = 4.74 + log(A-/HA)
0 = log(A-/HA)
A-/HA = 1
Consider X = moles of NaOH added (and moles of A- formed)
Remaining moles of HA = 1.8 - X
moles of A- = X
HA = 1.8 - X
X/(1.8-X) = 1
X =0.9
We have to add 0.9 mole NaOH to 1.0 L of 1.8 M HC2H3O2
To control we can do the following equation:
4.74 = 4.74 + log(0.9/0.9) = 4.74
b) What quantity (moles) of NaOH must be added to 1.0 L of 1.8 M HC2H3O2 to produce a solution buffered at pH = 4.00?
Step 1: Data given
Volume of HC2H3O2 = 1.0 L
Molarity of HC2H3O2 = 1.8 M
Ka = 1.8*10^-5
ph = 4
Step 2:
Use the Henderson-Hasselbalch equation.
pH = pKa + log(A-/HA)
4 = 4.74 + log(A-/HA)
-0.74 = log(A-/HA)
A-/HA = 0.182
Consider X = moles of NaOH added (and moles of A- formed)
Remaining moles of HA = 1.8 - X
moles of A- = X
HA = 1.8 - X
X/(1.8-X) = 0.182
X =0.277
We have to add 0.277 mole NaOH to 1.0 L of 1.8 M HC2H3O2
To control we can do the following equation:
4 = 4.74 + log(0.277/1.523)
c) What quantity (moles) of NaOH must be added to 1.0 L of 1.8 M HC2H3O2 to produce a solution buffered at pH = 5.00
Step 1: Data given
Volume of HC2H3O2 = 1.0 L
Molarity of HC2H3O2 = 1.8 M
Ka = 1.8*10^-5
ph = 5
Step 2:
Use the Henderson-Hasselbalch equation.
pH = pKa + log(A-/HA)
5 = 4.74 + log(A-/HA)
0.26 = log(A-/HA)
A-/HA = 1.82
Consider X = moles of NaOH added (and moles of A- formed)
Remaining moles of HA = 1.8 - X
moles of A- = X
HA = 1.8 - X
X/(1.8-X) = 1.82
X =1.16
We have to add 1.16 mole NaOH to 1.0 L of 1.8 M HC2H3O2
To control we can do the following equation:
5 = 4.74 + log(1.16/0.64) = 5
Explanation: