Answer: • Phe can undergo oxidation to form Tyr.
• The Ala side chain does not form hydrogen bonds with other amino acids.
• Thr and Ser are polar amino acids.
• Lysine has one stereocenter (chiral center).
Explanation:
Amino acids are simply organic compounds which are known to contain carboxyl and amine functional groups and the main elements that are found in an amino acid are oxygen, carbon, hydrogen, and nitrogen.
The true statements about amino acids are:
• Phe can undergo oxidation to form Tyr.
• The Ala side chain does not form hydrogen bonds with other amino acids.
• Thr and Ser are polar amino acids.
• Lysine has one stereocenter (chiral center).
It should be noted that Methionine is not a thiol but rather a thio ether. Also, proline is simply a neutral amino acid and the statement that proline has an overall charge at physiological
pH(7.4) is false.
For isotopic analysis, an ice core sample was heated to produce gaseous H2O. If 3.00 μg of gaseous H2O was injected into a mass spectrometer:
How many moles of water were injected? Answer: 1.67×10−7
If the sample contains 0.0156% deuterium, how many deuterium atoms were injected?
Answer:
1.67 × 10⁻⁷ mol H₂O
3.14 × 10¹³ atoms deuterium
Explanation:
How many moles of water were injected?
We have 3.00 μg of gaseous H₂O. To calculate the number of moles of water we will use the following relationships:
1 g = 10⁶ μgThe molar mass of water is 18.02 g/mol.[tex]3.00 \mu g \times \frac{1g}{10^{6}\mu g } \times \frac{1mol}{18.02g} = 1.67 \times 10^{-7} mol[/tex]
If the sample contains 0.0156% deuterium, how many deuterium atoms were injected?
We will use the following relationships:
1 mole of water contains 6.02 × 10²³ molecules of water.
There are 2 hydrogen atoms per water molecule.
0.0156% of hydrogen atoms are deuterium atoms.
[tex]1.67 \times 10^{-7} molH_2O \times \frac{6.02 \times 10^{23}moleculesH_2O }{1molH_2O} \times \frac{2atomsH}{1moleculeH_2O} \times 0.0156 \% = 3.14 \times 10^{13} atomsD[/tex]
The C_7 compound which gives 3 signals in the broadband proton-decoupled ^13C spectrum could be:______
a) Heptane
b) 2-Methylhexane
c) 3, 3-Dimethylpentane
d) 2, 4-Dimethylpentane
e) 2, 2, 3-Trimethylbutane
Answer:
d) 2, 4-Dimethylpentane
Explanation:
2, 4-Dimethylpentane is the c_7 compound that gives 3 signals in the broadband proton decoupled ¹³C spectrum.
This compound is classified as an alkane and it's chemical formula is [(CH3C)2CH]2CH2. It is a hydrocarbon that has no odor. When it is combined with other gas compounds it gives high octane fuel.
When comparing lithium, sodium, and potassium to calcium, strontium, and barium, early chemists noticed that:
Answer:
Explanation:
Lithium, Potassium and Sodium follow each other in that order when it comes to reactivity.
Succinctly put, Lithium is the most reactive. Potassium is more reactive and Sodium is the least reactive.
Also, for Calcium, Strontium and Barium. It is the least reactive in this order.
Strontium, Barium, Calcium
That is, Strontium is more reactive than Barium, which is more reactive than Calcium. Calcium is the least reactive of the 3
When an apple is cut, it often turns brown. What does the color change indicate?
A. physical change only
B. chemical change only
C. physical and chemical changes
Answer:
C
Explanation:
When an apple is cut (or bruised), oxygen is introduced into the injured plant tissue. When oxygen is present in cells, polyphenol oxidase (PPO) enzymes in the chloroplasts rapidly oxidize phenolic compounds naturally present in the apple tissues to o-quinones, colorless precursors to brown-colored secondary products
g Given that 50.0 mL of 0.100 M magnesium bromide reacts with 13.9 mL of silver nitrate solution according to the unbalanced equation MgBr21aq2 AgNO31aq2 S AgBr1s2 Mg1NO3221aq2 (a) What is the molarity of the AgNO3 solution
Answer:
0.719M AgNO₃
Explanation:
Based on the reaction:
MgBr₂ + 2AgNO₃ ⇄ 2AgBr + Mg(NO₃)₂
1 mole of magnesium bromide reacts completely with 2 moles of AgNO₃
To find molarity of AgNO₃ solution we need to determine moles of AgNO₃ and, as molarity is the ratio of moles over liter (13.9mL = 0.0139L). Now, to determine moles of AgNO₃ we need to use the reaction, thus:
Moles AgNO₃:
Moles of MgBr₂ are:
50.0mL = 0.050L * (0.100mol / L) = 0.00500 moles of MgBr₂.
As the silver nitrate reacts completely and 2 moles of AgNO₃ reacts per mole of MgBr₂:
0.00500 moles MgBr₂ * (2 moles AgNO₃ / 1 mole MgBr₂) =
0.0100 moles of AgNO₃ are in the solution.
And molarity is:
0.0100 moles AgNO₃ / 0.0139L =
0.719M AgNO₃what is dual behaviour of matter
Answer:
Dual nature of matter is an important concept in JEE physics and is basically the study of different nature that a matter possesses or exhibits. ... Hence, the matter is said to possess dual nature, i.e., it has both the properties of a particle and as well as a wave.
Iridium-192 is used in medicine to treat prostate cancer. Iridium-192 has two modes of radioactive decay: 96% of the time it decays by beta emission and 4% of the time it decays by electron capture. What are the daughter nuclides of these two decay processes?
Answer:
The daughter nuclides of these two decay processes are [tex]^{192}_{78}Pt [/tex] and [tex]^{192}_{76}Os[/tex].
Explanation:
The beta emission is represented by:
A = (Z + 1) + (n - 1) = is invariant
n: neutron
p: proton
[tex]^{A}_{Z}X \rightarrow ^{A}_{Z+1}Y[/tex]
Hence, the daughter nuclide of the beta emission of Ir-192 is:
[tex]^{192}_{77}Ir \rightarrow ^{192}_{78}Pt[/tex]
Now, electron capture is represented by:
A = (Z - 1) + (n + 1) = is invariant
[tex]^{A}_{Z}X \rightarrow ^{A}_{Z-1}Y[/tex]
Then, the daughter nuclide of the electron capture of Ir-192 is:
[tex]^{192}_{77}Ir \rightarrow ^{192}_{76}Os[/tex]
Therefore, the daughter nuclides of these two decay processes are [tex]^{192}_{78}Pt [/tex] and [tex]^{192}_{76}Os[/tex].
I hope it helps you!
What must be true of the free energy change, trangle G, for a reaction to be spontaneous?
A) It must be negative
B) it must be greater than the change in entropy
C) It is dominated by the enthalpy change, (triangle H)
D) It must be driven by a large change in both entropy and enthalpy
E) It must be positive
Answer:
A) It must be negative
Explanation:
A spontaneous reaction in Chemistry is that which is proceeding in a particular direction without the intervention of any external effect. As a spontaneous reaction proceeds (which can be relatively slow), free energy ΔG, which is the available energy for work, is released.
Gibbs free energy, ΔG, is released during a spontaneous process and hence the ΔG is negative because the reactants have more free energy than the products, hence, no energy input is needed for the reaction to proceed forward but rather an energy output. This is what makes a negative ΔG depict a spontaneous reaction.
Classify each substance based on the intermolecular forces present in that substance.
A. Hydrogen bonding, dipole dipole, and dispersion
B. Dipole dipole and dispersion only
C. Dispersion only
1. H2O
2. CH4
3. CO
4. CH2Cl
Answer:
H2O- Hydrogen bonding, dipole dipole, and dispersion
CH4- Dispersion only
CO- Dispersion only
CH2Cl- Dipole dipole and dispersion only
Explanation:
Dipole- dipole interactions exist only in molecules that have a dipole moment such as water and dichloromethane. Water experiences intermolecular hydrogen bonding in addition to dipole-dipole interaction and dispersion forces due to the O-H bond in the molecule.
Nonpolar compounds only have dispersion forces acting between its molecules.
Explanation:
When Dipole-dipole interactions exist only in molecules that have a dipole moment such as water and also that dichloromethane. After that Water experiences intermolecular hydrogen bonding in addition to dipole-dipole interaction and also that dispersion forces due to the O-H bond in the molecule. Thus, Nonpolar compounds only have dispersion forces acting between their molecules.Find out more information about dispersion here:
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The exhaust gas from an automobile contains 3% by volume of carbon monoxide (CO). Express this concentration in mg/m3 at 25oC and 1 atm.
Answer:
[tex]24540\frac{mg}{m^3}[/tex]
Explanation:
Hello,
In this case, since the 3% by volume is represented as:
[tex]\frac{3L\ CO}{L\ gas}[/tex]
By using the ideal gas equation we compute the density of CO:
[tex]\rho =\frac{MP}{RT} =\frac{28g/mol*1atm}{0.082\frac{atm*L}{mol*K}*298K}= 0.818g/L[/tex]
Then we apply the conversion factors as follows:
[tex]=\frac{3L\ CO}{100L\ gas}*\frac{0.818g\ CO}{1L\ CO} *\frac{1000mg\ CO}{1g\ CO} *\frac{1000L\ gas}{1m^3\ gas} \\\\=24540\frac{mg}{m^3}[/tex]
Regards.
What is the density of an object with a volume of 11.24 L and a mass of 3.45 g ?
Answer:
0.306 g/L
Explanation:
D = M/V
D= 3.45 g/11.24 L
D= 0.306 g/L
How many free neutrons are produced in each of the following uranium-235 fission reactions. (Please explain)
Answer:
A. 2
B. 3
C. 4
Explanation:
Please see attached photo for explanation.
Consider the following redox reaction: Ag⁺(aq) + Fe²⁺(aq) ⇌ Ag(s) + Fe³⁺(aq). How many moles of electrons are exchanged?
Answer:
1 mol of electron is exchanged. The mol of electrons that is released by the iron, is gained by the silver.
Explanation:
We need to determine the half reactions:
Ag⁺ → Ag
These is the reduction reaction, where Silver decreases the oxidation state. It gained 1 mol of e⁻
Fe²⁺ → Fe³⁺
In this case, iron increases the oxidation state, from +2 to +3. It has released 1 mol of electrons. This is the oxidation reaction.
The complete redox is:
Ag⁺ + 1e⁻ → Ag
Fe²⁺ → Fe³⁺ + 1e⁻
Ag⁺(aq) + 1e⁻ + Fe²⁺(aq) ⇌ Ag(s) + Fe³⁺(aq) + 1e⁻
The electrons will be cancelled.
In the redox reaction Ag⁺(aq) + Fe²⁺(aq) ⇌ Ag(s) + Fe³⁺(aq),
1 mole of electrons is exchanged.
Let's consider the following balanced redox reaction.
Ag⁺(aq) + Fe²⁺(aq) ⇌ Ag(s) + Fe³⁺(aq).
We can identify both half-reactions.
Reduction: Ag⁺(aq) + 1 e⁻ ⇌ Ag(s)Oxidation: Fe²⁺(aq) ⇌ Fe³⁺(aq) + 1 e⁻We can conclude that:
In the reduction, 1 mole of Ag⁺ gains 1 mole of electrons to form 1 mole of Ag.In the oxidation, 1 mole of Fe²⁺ loses 1 mole of electrons to form 1 mole of Fe³⁺All in all, 1 mole of electrons is exchanged.In the redox reaction Ag⁺(aq) + Fe²⁺(aq) ⇌ Ag(s) + Fe³⁺(aq),
1 mole of electrons is exchanged.
Learn more: https://brainly.com/question/2671074
What food color mix to make yellow?
Answer:
read and green
Explanation:
By convention, the three primary colors in additive mixing are red, green, and blue. In the absence of light of any color, the result is black. If all three primary colors of light are mixed in equal proportions, the result is neutral (gray or white). When the red and green lights mix, the result is yellow.
Answer:
ground tumeric
Explanation:
Mix 1/4 cup water and 1/2 teaspoon of ground tumeric
Based on Figure 25-2, are red giants hotter than white dwarfs?
Answer:
No
Explanation:
A white dwarf has a higher surface temperature than a red giant.
Explain the concept of significant figures and why it is important in scientific experiments.
Answer:
Significant figures (also called significant digits) are an important part of scientific and mathematical calculations, and deals with the accuracy and precision of numbers. It is important to estimate uncertainty in the final result, and this is where significant figures become very important.
Explanation:
Read “The Ozone Hole” and answer the question below. Write a short evaluation of the article’s reliability and scientific worth. Support your evaluation with specific examples from the article.
Answer:
The article presented evidence of ozone damage from NASA, which is a reliable source. The article discussed scientific studies published in a reputable journal. The article presented scientific facts and historical facts and did not present any opinions.
The ozone layer is a shield district of Earth's stratosphere that ingests a large portion of the Sun's bright radiation. It contains a high grouping of ozone (). It contains atoms of oxygen that keep the environment from hurtful beams that are available in space and boundless by the sun, for instance, bright beams.
Is there still a hole in the ozone layer in 2020?Scientists from the Copernicus Atmosphere Monitoring Service confirm that the 2021 Antarctic ozone hole has almost reached its end, following a season with a considerably large and prolonged ozone hole. Its closure will occur only a few days earlier than in 2020, which was the longest-lived since 1979.
Has the ozone hole closed?It closed on 23 December, the third latest date after 1999 and 2020. The extent and longevity of the 2021 ozone hole can be explained by very cold temperatures in the stratosphere and a very stable polar vortex. This video shows the evolution of the 2021 Antarctic ozone hole.
Learn more about The Ozone Hole at
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Consider a 0.238 M aqueous solution of sodium hydroxide, NaOH.
a. How many grams of NaOH are dissolved in 23.46 mL?
b. How many individual hydroxide ions (OH) are found in 23.46 mL?
c. How many moles of sulfuric acid, H2SO4, are neutralized by 23.46 mL of 0.238 M NaOH(aq)? [Hint: begin by writing a balanced equation for this neutralization reaction.]
Answer:
The correct answer is a. 0.223 grams, b. 3.36 × 10²¹ and c. 2.79 × 10⁻³ mol.
Explanation:
a. The volume of the solution given is 23.46 ml or 23.46 × 10⁻³ L, the molarity of NaOH is 0.238 M or 0.238 mol/L. Now the number of moles of NaOH will be,
Number of moles = Molarity × Volume in Liters of solution
= 0.238 mol/L × 23.46 × 10⁻³ L
= 5.5835 × 10⁻³ mol
Now the mass of NaOH will be,
= Moles × Molecular mass of NaOH
= 5.5835 × 10⁻³ mol × 39.997 g/mol
= 223.322 × 10⁻³ grams
b) The number of moles in 23.46 ml is 5.5835 × 10⁻³ mol
Now the number of hydroxide ions found will be,
= No. of moles × NA
= 5.5835 × 10⁻³ × 6.022 × 10²³
= 3.36 × 10²¹
c) The balanced chemical equation is,
2NaOH + H₂SO₄ ⇒ Na₂SO₄ + 2H₂O
The number of moles of H₂SO₄ neutralized is,
= Number of moles of NaOH taken/2
= 5.5835 × 10⁻³/2 mol
= 2.7917 × 10⁻³ mol
Water vapor in the morning turns into dew on the grass.
Answer:
Dew is liquid water droplets that form on grass, spider webs, and other things in the early morning or late evening. ... That means it turns from a liquid into a gas called "water vapor." When evening comes, the warm ground continues to radiate heat into
What effect does decreasing the temperature of a room have on a lifespan of a battery?
Which variable is highlighted in red, bolded tex?
a
Independent
b
Dependent
c
Control
d
None
Answer:
This question is incomplete. There is no highlight in red bolded text in the question but the answer to both the independent and dependent variables will be provided and explained in details.
Independent variable: decrease in temperature
Dependent variable: lifespan of battery
Explanation:
The independent variable of an experiment refers to the variable that is changed or manipulated by the experimenter in order to bring about an outcome. In this experiment, the DECREASE IN TEMPERATURE is the independent variable because it is what is being changed to effect a response in the battery lifespan.
On the contrary, the dependent variable is the variable that responds to the manipulation of the independent variable. In other words, the dependent variable is the outcome. In this experiment, the LIFESPAN OF THE BATTERY is the dependent variable because it is what is responding to the changes made by decreasing the temperature (independent variable)
A textbook measures 250 mm long, 225 mm wide and 50 mm thick. What is the volume of this book in mm3? What is the volume of this book in m3?
Answer:
2.81 × 10⁶ mm³
2.81 × 10⁻³ m³
Explanation:
Step 1: Given data
Length (l): 250 mm
Width (w): 225 mm
Thickness (t): 50 mm
Step 2: Calculate the volume of the textbook
The book is a cuboid so we can find its volume (V) using the following expression.
V = l × w × t = 250 mm × 225 mm × 50 mm = 2.81 × 10⁶ mm³
Step 3: Convert the volume to cubic meters
We will use the relationship 1 m³ = 10⁹ mm³.
2.81 × 10⁶ mm³ × 1 m³ / 10⁹ mm³ = 2.81 × 10⁻³ m³
Convert 7.61x10-5 L to picoliters.
Answer:
38,050,000,000,000 picoliters.
Explanation:
10-5=5, 7.61 x 5=38.05 (38.05L)
every liter is equal to 1000000000000 picoliters, so you go from there and just multiply 1000000000000 by 38.05.
The pKb of the base cyclohexamine, C6H11NH2, is 3.36. What is the pKa of the conjugate acid, C6H11NH3
Answer:
10.64
Explanation:
Let's consider the basic reaction of cyclohexamine, C₆H₁₁NH₂.
C₆H₁₁NH₂(aq) + H₂O(l) ⇄ C₆H₁₁NH₃⁺(aq) + OH⁻ pKb = 3.36
C₆H₁₁NH₃⁺ is its conjugate acid, since it donates H⁺ to form C₆H₁₁NH₂. C₆H₁₁NH₃⁺ acid reaction is as follows:
C₆H₁₁NH₃⁺(aq) + H₂O(l) ⇄ C₆H₁₁NH₂(aq) + H₃O⁺(aq) pKa
We can find the pKa of C₆H₁₁NH₃⁺ using the following expression.
pKa + pKb = 14.00
pKa = 14.00 - pKb = 14.00 - 3.36 = 10.64
The pKa of conjugate acid of cyclohexamine has been 10.64.
The pKa has been acid dissociation constant, and has been describing the hydrogen ion concentration in the sample.
The pKb has been the base dissociation constant and has been describing the hydroxide ion concentration in the sample.
The sum of pKa and pKb has been found to be 14.
[tex]\rm pKa \;+\;pKb=14[/tex]
The pKb of cyclohexamine has been 3.36. The pKa of conjugate acid in the sample has been given by substituting the values as:
[tex]\rm pKa\;+\;3.36=14\\pKa=14\;-\;3.36\\pKa=10.64[/tex]
The pKa of conjugate acid of cyclohexamine has been 10.64.
For more information about pKa and pKb, refer to the link:
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(a) Atoms are very small compared to objects on the macroscopic scale. The radius of a platinum atom is 139 pm. What is this value in meters and in centimeters? ____m ____cm
( b) The mass of a single platinum atom is 3.24*1022 g. Suppose enough Pt atoms were lined up like beads on a string to span a distance of 48.1 cm (19 inches) How many atoms would be required? ___atoms
What mass in grams of Pt would be used? ___g
Could you weigh out this amount of platinum using a typical laboratory balance? Yes or no?
(c) Taking the density of platinum metal to be 21.4 g/cm^3, calculate the mass of metal needed to form a piece of Pt wire with the same length as the distance in b, but with a diameter of atoms 1.50 mm. Hint: The volume of a cylinder is π times its radius squared times its height (V = πr^2h) ___g
How many platinum atoms does this represent? ____atoms
Answer:
Kindly check explanation
Explanation:
pm = picometer
Radius of platinum atom = 139 pm
1 pm = 1 × 10^-12 m
Hence,
139 pm = 139 × 10^-12 m
1 pm = 1 × 10^-10 cm
Hence,
139 pm = 139 × 10^-10 cm
B) mass of a single platinum atom = 3.24 × 10²² g
To obtain the diameter of 1 platinum atom in cm:
139 × 10^-10 cm
Number of atoms required :
48.1 cm / 1.39 × 10^-8 cm = 34.60 × 10^8 atoms
Mass in gram of P(t) :
(3.24 × 10²²) × (34.60 × 10^8) = 112.117 × 10^(22+8)
= 112.12 × 10^30 g
C) density (d) = 21.4 g/cm^3, diameter = 1.50 mm
V = πr^2h
h = 48.1cm ; r = 1.5 / 2 = 0.75 mm = 0.075cm
Density = mass / volume
Volume = π * 0.075^2 * 48.1 = 0.8499971cm³
Mass = density × volume
Mass = 21.4g/cm³ × 0.8499971cm³
= 18.19g
The principle applied to the design of an airplane wing was developed by
Answer:
Bernoulli’s PrincipleThis states principle helps explain that an aircraft can achieve lift due to the shape of its wings.
They wings are shaped that way so that that air flows faster over the top of the wing and slower underneath the wing .
In simple terms ;
Fast moving air equals low air pressure while slow moving air equals high air pressure
Explanation:
Calculate the pH of the resulting solution if 23.0 mL of 0.230 M HCl(aq) is added to 28.0 mL of 0.230 M NaOH(aq) .
Answer:
pH = 12.35
Explanation:
The HCl reacts with NaOH, thus:
HCl + NaOH → NaCl + H₂O
1 mole of HCl reacts per mole of NaOH
To know the pH we must know the moles of NaOH and the moles of HCl that reacts
Moles NaOH and HCl
NaOH: 0.0280L * (0.230mol / L) = 6.44x10⁻³ moles
HCl: 0.0230L * (0.230mol / L) = 5.29x10⁻³
As moles NaOH > Moles HCl, the moles that remains of NaOH are:
Moles NaOH = 6.44x10⁻³ - 5.29x10⁻³ = 1.15x10⁻³ moles NaOH = Moles OH⁻
In 23.0mL + 28.0mL = 51.0mL = 0.0510L:
1.15x10⁻³ moles OH⁻ / 0.0510L =
0.0225M OH⁻
pOH = -log [OH⁻]
pOH = 1.647
And pH = 14 - pOH
pH = 12.35Which pair of compounds will form a buffer in aqueous solution? a) HCN and NaCN b) HCl and NaOH c) NaCN and NaOH d) HCN and HCl e) HCl and NaCl f) NaCN and KCN
Answer:
a) HCN and NaCN
Explanation:
Buffer solution is made by mixing either a weak base and its salt like ammonia and ammonium chloride or weak acid and its salt like HCN and its salt NaCN or acetic acid and sodium acetate .
In the given option , all of the rest of option has either strong acid or strong base or both . In the last option both are salt so it can not form buffer solution .
It is capable of keeping the pH of the solution constant .
What is the molarity (M) of an 85.0-mL solution (total volume) containing 1.77 g of ethanol (C2H5OH)
Answer: The molarity of solution is 0.453 M
Explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.
[tex]Molarity=\frac{n\times 1000}{V_s}[/tex]
where,
n = moles of solute
[tex]V_s[/tex] = volume of solution in ml
moles of [tex]C_2H_5OH[/tex] = [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{1.77g}{46g/mol}=0.0385mol[/tex]
Now put all the given values in the formula of molality, we get
[tex]Molarity=\frac{0.0385\times 1000}{85.0}[/tex]
[tex]Molarity=0.453[/tex]
Therefore, the molarity of solution is 0.453 M
If E°(red) of a given half-cell is more negative than E°(red) for a standard hydrogen electrode, the half-cell will:
Answer:
Be the anode
Explanation:
The standard hydrogen electrode is regarded as the standard reference electrode and it has been assigned an electrode potential of 0.0V.
If any substance has an electrode potential that is more negative than hydrogen, then that half cell will function as the anode when connected to the standard hydrogen electrode.
Similarly, any substance that has a more positive electrode potential than hydrogen will serve as the cathode when its half cell is connected to the standard hydrogen electrode.
Calculate the concentration and pH of a M aqueous solution of sodium cyanide, . Finally, calculate the concentration. ()
Answer:
[OH⁻] = 0.000324619M
pH = 10.51
[CN⁻] = 5.175x10⁻³M
Explanation:
Full question says:
Calculate the OH- concentration and pH of a 5.5×10-3M aqueous solution of sodium cyanide, NaCN. Finally, calculate the CN- concentration.
Ka (HCN) = 4.9×10-10
Sodium cyanide, is in equilibrium with water as follows:
NaCN(aq) + H₂O(l) ⇄ HCN(aq) + OH⁻(aq)
Where Kb (Kb = Kw / Ka = 1x10⁻¹⁴ / 4.9x10⁻¹⁰ = 2.04x10⁻⁵) is:
2.04x10⁻⁵ = [HCN] [OH⁻] / [NaCN]
In equilibrium, ann amount of HCN and OH⁻ is produced = X and the molarity of NaCN is: 5.5x10⁻³M - X
Replacing in Kb expression:
2.04x10⁻⁵ = [X] [X] / [5.5x10⁻³M - X]
1.12x10⁻⁷- 2.04x10⁻⁵X = X²
1.12x10⁻⁷- 2.04x10⁻⁵X - X² = 0
Solving for X:
X = -0.0003 → False solution. There is no negative concentrations
X = 0.000324619
As [OH⁻] = X.
[OH⁻] = 0.000324619MpOH = -log [OH⁻]
pOH = 3.489
pH = 14 -pOH
pH = 10.51And as molarity of NaCN = [CN⁻] = 5.5x10⁻³M - X
[CN⁻] = 5.175x10⁻³M