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:
The Kp for the reaction A (g) = 2 B (g) is 0.0380. What is Kp for the reaction 4 B (g) = 2 A (g)?
Answer:
692.52
Explanation:
First Reaction;
A (g) = 2 B (g)
Kp is given as; (PB)² / (PA)
But Kp = 0.0380
So we have;
(PB)² / (PA) = 0.0380
Second Reaction;
4 B (g) = 2 A (g)
Kp is given as; (PA)² / (PB)⁴
The relationship between Kp expressions for both reactions is given as;
Second Reaction Kp = 1 / (First Reaction Kp)²
Second Reaction Kp = 1 / (0.0380)² = 1/0.001444
Second Reaction Kp = 692.52
1. Assume this experiment (after the extractions are complete) left you with 4 pure products (aspirin, acetaminophen and caffeine, and the binder). Your lab mate distracted you after you had labeled the binder and now you can’t remember which of the remaining 3 products is which. What would be a simple test that you can perform in the laboratory to distinguish between the 3 remaining solids isolated from your experiments?
Answer:
Explanation:
Out of aspirin, acetaminophen and caffeine, aspirin is an acid because it is acetyl saliciylic acid . Hence it can be tested with litmus paper .
acetaminophen contains phenolic functional group , hence it is a weak acid . It can be tested with any test with which phenol test are done, like with neutral solution of ferric chloride .
caffeine is weak basic substance . It can also be tested with the help of testing a basic substance .
What type of wave does not need matter to carry energy?
The answer is Electromagnetic
Answer:
Electromagnetic
Explanation:
Electromagnetic waves differ from mechanical waves in that they do not require a medium to propagate. This means that electromagnetic waves can travel not only through air and solid materials, but also through the vacuum of space.
In a covalent bond electron pairs are
Answer:
A covalent bond, also called a molecular bond, is a chemical bond that involves the sharing of electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs, and the stable balance of attractive and repulsive forces between atoms, when they share electrons, is known as covalent bonding.Explanation:have a good day :P
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:
it is the main factor of contact metamophism.
Answer:
The size of a contact aureole depends on a number of factors that control the rate at which heat can move out of the pluton and into the surrounding country rock. Among these factors are: The size and temperature of the intrusion. This will control how much heat is available to heat the surrounding country rocks
Explanation:
Hope this helps u
crown me as brainliest
The first energy level which has p orbitals to fill is ___
1
2
3
4
Answer:
2
Explanation:
The Aufbau sequence of increasing energy levels is 1s,2s,2p,3s,3p,4s,3d and so on....
Hope this helps! :D
Which statement explains why NaBr is classified as a compound?
1.
Na and Br are chemically combined in a fixed proportion.
2.
Na and Br are both nonmetals.
3
NaBr is a solid
298 Kand standard pressure.
4.
NaBr dissolves in H20 at 298 K.
Submit
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Answer:1
Explanation:i know cuz I got it right
NaBr is classified as a compound because sodium and bromine are chemically combined in a fixed proportion.
Explanation:
Element is defined as the simplest form of a substance that cannot be divided further by any physical means.For example oxygen ([tex]O_2[/tex]), coal (carbon) etc.A compound is defined as the form of a substance in which two or more different elements are chemically combined together in a fixed proportion.For example sodium chloride (NaCl), nitric acid ([tex]HNO_3[/tex])A compound can be further divided into a simple substance.So, from this, we can conclude that NaBr is classified as a compound because sodium and bromine are chemically combined in a fixed proportion.
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Solid diarsenic trioxide reacts with fluorine gas (F2) to produce liquid arsenic pentafluoride and oxygen gas (O2). Write the Qc for this reaction.
Answer:
QC= [O2]^3/[F2]^10
Explanation:
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
Joebert had a rectangular cup and filled it with water. He measured the water's mass and volume. Then he got a density of 1.25g/ml. If the accepted density of water is 1 g/ml, what was the percent error of his measurement?
someone can help me please?
Answer:
Percent error = 25%
Explanation:
Given data:
Measured density of water = 1.25 g/mL
Accepted density value of water = 1 g/mL
Percent error = ?
Solution:
Formula:
Percent error = (measured value - accepted value / accepted value) × 100
Now we will put the values in formula:
Percent error = (1.25 g/mL - 1 g/mL /1 g/mL )× 100
Percent error = (0.25 g/mL /1 g/mL )× 100
Percent error = 0.25 × 100
Percent error = 25%
Need help on 6 and 7 or just one please help
What concentration of NO−3NO3− results when 897 mL897 mL of 0.497 M NaNO30.497 M NaNO3 is mixed with 813 mL813 mL of 0.341 M Ca(NO3)2?
Answer:
Explanation:
NaNO₃ = Na⁺ + NO₃⁻¹
.497 M .497 M
moles of NO₃⁻¹ = .897 x .497 = .4458 moles
Ca( NO₃)₂ = Ca + 2 NO₃⁻¹
.341 M 2 x .341 M = .682 M
moles of NO₃⁻¹ = .813 x .682 = .5544 moles
Total moles = .4458 moles + .5544 moles
= 1.0002 moles
volume of solution = 897 + 813 = 1710 mL
= 1.710 L
concentration of nitrate ion = 1.0002 / 1.710 M
= .585 M
Radium decays to form radon. Which equation correctly describes this decay? Superscript 226 Subscript 88 Baseline Upper R a right arrow Superscript 222 Subscript 84 Baseline Upper R n + Superscript 4 Subscript 4 Baseline Upper H e Superscript 226 Subscript 88 Baseline Upper R a right arrow Superscript 222 Subscript 86 Baseline Upper R n + Superscript 0 Subscript negative 1 Baseline e Superscript 226 Subscript 88 Baseline Upper R a right arrow Superscript 222 Subscript 86 Baseline Upper R n + Superscript 0 Subscript + 1 Baseline e Superscript 226 Subscript 88 Baseline Upper R a right arrow Superscript 222 Subscript 86 Baseline Upper R n + Superscript 4 Subscript 2 Baseline Upper H e
Answer: 226 Subscript 88 Baseline Upper R a right arrow Superscript 222 Subscript 86 Baseline Upper R n + Superscript 4 Subscript 2 Baseline Upper H e
Explanation:
Alpha decay : When a larger nuclei decays into smaller nuclei by releasing alpha particle. In this process, the mass number and atomic number is reduced by 4 and 2 units respectively.
The general representation of alpha decay reaction is:
[tex]^{A}_{Z}\textrm{X}\rightarrow ^{A-4}_{Z-2}\textrm {Rn}+ ^{4}_{2}\textrm{He}[/tex]
Representation of Radium decays to form Radon
[tex]^{226}_{88}\textrm{Ra}\rightarrow ^{222}_{86}\textrm {Rn}+ ^{4}_{2}\textrm{He}[/tex]
Thus 226 Subscript 88 Baseline Upper R a right arrow Superscript 222 Subscript 86 Baseline Upper R n + Superscript 4 Subscript 2 Baseline Upper H e represents alpha decay.
Answer: D
Explanation:
On edge 2020
describe a scenario where there is high effort, but no work performed
Answer:danceing
Explanation:
How long would it take a bus traveling 52 km/h to travel 130 km
Answer:
2 and a half hours
Explanation:
Time is equal to distance over speed
4. What reagent would you predict to be in excess for reacting 7.50 mL of a 0.10M BaCl2 solution with 7.50 mL of 0.10M KIO3 solution
Answer : [tex]BaCl_2[/tex] reagent predict to be in excess.
Explanation : Given,
Concentration of [tex]BaCl_2[/tex] = 0.10 M
Volume of [tex]BaCl_2[/tex] = 7.50 mL = 0.0075 L (1 L = 1000 mL)
Concentration of [tex]KIO_3[/tex] = 0.10 M
Volume of [tex]KIO_3[/tex] = 7.50 mL = 0.0075 L
First we have to calculate the moles of [tex]BaCl_2[/tex] and [tex]KIO_3[/tex].
[tex]\text{Moles of }BaCl_2=\text{Concentration of }BaCl_2\times \text{Volume of }BaCl_2[/tex]
[tex]\text{Moles of }BaCl_2=0.10M\times 0.0075L=0.00075mol[/tex]
and,
[tex]\text{Moles of }KIO_3=\text{Concentration of }KIO_3\times \text{Volume of }KIO_3[/tex]
[tex]\text{Moles of }KIO_3=0.10M\times 0.0075L=0.00075mol[/tex]
Now we have to calculate the excess and limiting reagent.
The balanced equilibrium reaction will be:
[tex]BaCl_2+2KIO_3\rightleftharpoons Ba(IO_3)_2+2KCl [/tex]
From the balanced reaction we conclude that
As, 2 mole of [tex]KIO_3[/tex] react with 1 mole of [tex]BaCl_2[/tex]
So, 0.00075 moles of [tex]KIO_3[/tex] react with [tex]\frac{0.00075}{2}=0.000375[/tex] moles of [tex]BaCl_2[/tex]
From this we conclude that, [tex]BaCl_2[/tex] is an excess reagent because the given moles are greater than the required moles and [tex]KIO_3[/tex] is a limiting reagent and it limits the formation of product.
Hence, [tex]BaCl_2[/tex] reagent predict to be in excess.
what happens when a solution of an acid is mixed with a solution of a base in a test tube?
Answer:
Explanation:
When acid is mixed with a solution of base it results in a neutralization reaction. Neutralization is an exothermic reaction which results in the formation of salt.
Which phase change results in an increase in entropy?
1.
12(9) - 12(s)
2.
CH2(g) - CH40
3.
Br2(1) - Br2(g)
4.
H20(1) - H20(s)
The phase change that results in an increase in entropy is the change; Br2(1) - Br2(g)
What is entropy?The term entropy refers to the degree of disorderliness in a system. We have to note that gases have a higher entropy than liquids and liquids have a higher entropy than the solids.
As such, the phase change that results in an increase in entropy is the change; Br2(1) - Br2(g)
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Based on position in the periodic table and electron configuration, arrange these elements in order of decreasing Ei1.
Rank the elements from highest to lowest ionization energy. To rank items as equivalent, overlap them.
S, As, Ga, Se, K, Rb
Answer:
Rb<K<Ga<As<Se<S
Explanation:
We must remember that first ionization energy decreases down the group and increases across the period.
First ionization energy decreases down the group because of the addition of more shells which increases the distance between the nucleus and the outermost electron. Hence, Rb has a lower ionization energy that K.
Across the period, increase in the size of the nuclear charge causes the pull of the nucleus on the outermost electrons to increase thereby increasing the ionization energy. Hence ionization energy increases across the period. For this reason, the ionization energy of Ga<As<Se as shown.
Ionization energy is the energy required to remove an electron from an atom of a chemical element. Ionization energy depends on the atomic radius of an element.
Ionization energy and the periodic table.
Ionization energy increase across the period from left to right and decreases along the group from top to bottom on the periodic table.
Ranking the elements from highest to lowest ionization energy, We have:
S - Sulphur
S - SulphurK - Potassium
S - SulphurK - PotassiumRb - Rubidium
S - SulphurK - PotassiumRb - RubidiumSe - Selenium
S - SulphurK - PotassiumRb - RubidiumSe - SeleniumAs - Arsenic
S - SulphurK - PotassiumRb - RubidiumSe - SeleniumAs - ArsenicGa - Gallium
Read More:
Ionization energy is a measure of how strongly an atom holds onto its electrons. A higher ionization energy indicates th...
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Why is Newton's 1st Law also known as the Law of Inertia?
Answer:
Law of Inertia it's also called Newton's first law of motion simply stated it means an object in motion tends to stay in motion or an object at rest tends to stay at rest unless the object is acted upon by an unbalanced force. Hope this helped!
Answer:
It means an object in motion tends to stay in motion or an object at rest tends to stay at rest unless the object is acted upon by an unbalanced force.
Determine the pH of a 0.461 M C6H5CO2H M solution if the Ka of C6H5CO2H is 6.5 x 10-5. Determine the pH of a 0.461 M C6H5CO2H M solution if the Ka of C6H5CO2H is 6.5 x 10-5. 11.74 9.48 5.48 4.52 2.26
Answer:
the answer
Explanation:
the answer
The pH of the solution can be calculated using the Ka value and molarity of the acid. pH of the acid is obtained as 2.26.
What is pH?pH of a solution is the measure of acidity or basicity. Mathematically it is the negative logarithm of H+ ion concentration in the solution.
pH = - log [H+]
The constant Ka is called ionization constant of an acid. Acetic acid ionizes into equimolar concentrations of H+ and CH₃COO- ions. The Ka can be written as:
[tex]\rm K_{a} = \frac{[CH_{3}COO^{-}][H+]}{[CH_{3}COOH]}[/tex]
Where, [CH₃COO-] = [H+] Thus the expression becomes changed and from the values of Ka and molarity of the acid, H+ ion concentration can be calculated.
6.5 × 10⁻⁵ = [H+]² / [0.461 M]
[H+] = 0.0054.
Now, the pH can be calculated as follows:
pH = - log [0.0054]
= 2.26.
Therefore, the pH of the acidic solution is 2.26.
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The atomic notation for a particular atom of boron is ' B. The
atomic number is while the mass number is
Answer:
5;11
Explanation:
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
A balloon contains 1.1 L of gas at a pressure of 0.80 atm. How will the volume
change if the pressure is increased to 2.0 atm?
Answer:
Final volume = 0.44 L
Explanation:
Given data:
Initial volume of balloon = 1.1 L
Initial pressure = 0.80 atm
Final volume = ?
Final pressure = 2.0 atm
Solution:
The given problem will be solved through the Boly's law,
"The volume of given amount of gas is inversely proportional to its pressure by keeping the temperature and number of moles constant"
Mathematical expression:
P₁V₁ = P₂V₂
P₁ = Initial pressure
V₁ = initial volume
P₂ = final pressure
V₂ = final volume
Now we will put the values in formula,
P₁V₁ = P₂V₂
0.80 atm × 1.1 L = 2.0 atm × V₂
V₂ = 0.88 atm. L/ 2.0 atm
V₂ = 0.44 L
Please help me . I attached a picture down below . I need a answer as soon as possible
Answer:
I can't see the picture.. Can you try attaching it again?
Explanation:
If a substance has a density pf 2.5 g/cm³ how much mass will 50 cm³ of it have
Answer:
Density often has units of grams per cubic centimeter (g/cm3). Remember, grams is a mass and cubic centimeters is a volume (the same ... and minerals since the density of substances rarely changes significantly. For example, gold will always have a density of 19.3 g/cm3; if a mineral has a density
Explanation:
For example, a 1-litre soda bottle filled with air would feel much lighter than the same ... If 500 mL of a liquid has a density of 1.11 g/mL, what is its mass? ... The density of water at 4oC can be written as 1.000g/cm3 , 1.000g/mL ... In order to determine the density of a substance, you need to know its mass and its volume.
If a substance has a density of 2.5 grams/centimeters³ then the mass of the substance having a volume of 50 centimeters³ would be 75 grams.
What is density?It can be defined as the mass of any object or body per unit volume of the particular object or body. Generally, it is expressed as in gram per cm³ or kilogram per meter³.
As given in the problem If a substance has a density of 2.5 grams/centimeters³ then we have to find out the mass of the substance which has a volume of 50 centimeters³
the density of the substance = mass of the substance /volume of the substance
2.5 grams/centimeters³ = mass of the substance/50 centimeters³
mass of the substance = 2.5 ×50
= 75 grams
Thus, the mass of the substance would be 75 grams.
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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!
Magnesium oxide is 60.3% magnesium by mass. What is the mass fraction of magnesium in magnesium oxide?
a. 0.603
b. 0.397
c. 39.7
d. 60.3
e. None of these
Answer:
A. 0.603
Explanation:
Mass fraction of an element in a substance = mass of that element / total mass of the substance.
Mass of magnesium = 24.3g/mol
Mass of oxygen = 16g/mol
Total mass of MgO = 24.3+16 = 40.3g/mol
Hence, the mass fraction of magnesium in Magnesium oxide =
24.3/40.3
= 0.6029
= 0.603
Another way is to divide the percentage by mass of magnesium by 100 i.e. 60.3% = 60.3/100
= 0.603
What happens to the particles in a berry sauce mixture as it boils?
Answer:
The particles garner more and more energy as the boiling continues and thus the energy particles would find a way to escape from it's surface and ultimately the sauce will get to a point where it will turn to gas.
Explanation:
When berry sauce is boiling, it's particles will garner more energy and therefore will move at an increasing faster rate which makes the sauce to continuously expand. Now, the hotter the boiling gets, the more the most energetic particles located at the surface of the sauce will escape from the surface of the sauce. This is because liquids usually evaporate faster when they undergo heating and more particles will have sufficient energy to break away.
As boiling continues, it will get to a point that even particles in the middle of the sauce will begin to form bubbles of gas and at this point, the sauce would have achieved sufficient heat that it will begin to turn to gas.
