an acetate buffer has a ph of 4.40. which of the following changes will cause the ph to decrease?
The pH will decrease if more acid, such as a small amount of HCl, is added to the buffer system. To dissolve 246.1 g of sodium acetate, combine it with 500 mL of deionized water.
The pH can be increased to 5.2 by using glacial acetic acid. It is advisable to let the solution cool over night. You can increase the pH by one more point to 5.2 by using glacial acetic acid. By adding sodium from the conjugate base, a weak acid solution's pH can be raised. This makes sense because adding a base should increase the pH of a weak acid sodium solution, and sodium acetate is a basic.
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Which of the following combined elements will most likely form a covalent bond?
a. k and ci
b. h and o
c. ai and mg
d. k and na
Answer:
b. h and o are likely to form covalent bond
Which redox reaction would most likely occur if silver and zinc metal were added to a solution that contained silver and zinc?
The redox reaction which would most likely occur if silver and zinc metal were added to a solution that contained silver and zinc is Zn + Ag[tex]^+[/tex] [tex]\rightarrow[/tex]Zn[tex]^2+[/tex] + 2 Ag .
What is redox reaction?Redox reactions comprise of two parts a reduced part and an oxidized part, which occur simultaneously . The part which is reduced gain electrons and hence there is a increase in oxidation state of the species.
While, the part which is oxidized looses electrons and hence there is a decrease in oxidation state of the species.During redox reactions, there is no net change in the number of electrons . Electrons which are given off in oxidation are used up in reduction.
The ion or molecule which accepts electrons is called as oxidizing agent while the ion or molecule which donates electrons is called as a reducing agent.
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commercial vinegar is a 5.00% by mass aqueous solution of ethanoic acid. what is the molarity of ethanoic acid in vinegar? you may assume that the density of vinegar is 1.00 g/ml.
The Molarity of the ethanoic acid in Vinegar is 0.83 M. This is calculated using the expression for molarity.
Molarity is used for expressing how much solute is present per unit volume of solution.
Molarity (M)=n / V,
where n is moles of solute and V is volume of solution in liters.
The mass percentage of ethanoic acid in vinegar is 5.00%.
This suggests that for 100 g of vinegar, 5 g of it is ethanoic acid and 95 g of it is water.
We also know that the molar mass of ethanoic acid is 60.052 g/mol.
let us consider 100 g of vinegar. For finding the molarity of ethanoic acid in vinegar, we need to find the number of moles of ethanoic acid and the volume of vinegar.
Moles of ethanoic acid in 100 g of vinegar,
n=Given mass of ethanoic acid / Molar mass of ethanoic acid
= 5 gram / 60.052 g/ mole
= 0.083 mole
so, the molarity of ethanoic acid is,
molarity = 0.083 mole / 0.1 L
= 0.83 M
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PLEASE HELP I AM SO BEHIND ON SCHOOLWORK AND I HAVE TO GET IT ALL DONE BY FRIDAY!!
Which physical adaptation increases an organism’s chances of finding a suitable habitat?
Responses
the long legs of wading birds
the venom of snakes
the croak of frogs
the quills of a porcupine
a volume of methane gas is heated from to at constant pressure. what is the final volume of the gas? be sure your answer has the correct number of significant digits.
At constant pressure, a volume of methane gas is heated from to. The gas has a final volume of 44.1 L.
Methane is a colorless gas with no discernible odor. Due to overtone bands, it does absorb visible light, especially at the red end of the spectrum, although the impact is only apparent if the light path is very lengthy.Since pressure is constant, it also cancels with n and r when using the equation v1/t1 = v2/t2 and the law pv=nrT. demonstrate that t1 = 25 + 273.15; t2 = 88 + 273.15; and v1 = 36.4. 273.15 is the Kelvin conversion. then figure out v2. It contains 44.1 L.
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complete question
A 36.4-l volume of methane gas is heated from 25°c to 88°c at constant pressure. what is the final volume of the gas?
assuming standard conditions, this reaction is spontaneous at 298 k. at what temperature will this reaction reverse spontaneity, still assuming standard conditions?
The thermodynamic equilibrium constant In a chemical equilibrium, K is the appropriate quotient of species activities. At normal temperatures and pressures, an activity cannot be very many orders of magnitude more than one.
The definition of thermodynamic properties is "system characteristics that can specify the state of the system." Some constants, like R, are not attributes since they do not describe the state of a system. Thermodynamics states that the conversion of diamond to graphite occurs spontaneously and is favourable. However, this reaction moves extremely slowly because kinetics, not thermodynamics, regulates it. As a result, diamond is thermodynamically unstable but kinetically stable. An axiomatic idea in thermodynamics is the concept of equilibrium. One thermodynamic system's internal state, or a relationship between numerous thermodynamic systems, is what it is.
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Where does most of Earth's available carbon come from?
A. the constant process of photosynthesis
B. sunlight that is transferred from the Sun to Earth
C. the convection process that occurs in Earth's mantle
D. dead organisms that are recycled back into the environment
Answer: the constant process of photosythesis
Explanation:
it say in the etxt book
what is the vapor pressure (in torr) of a subtance at 36 c, whose normal boiling point is 84 c and has a delta hvap of 22.1 kj / mo
The vapor pressure of a substance is 241 Torr that can be calculated using Clausius-Clapeyron relation.
The Clausius-Clapeyron relation is used to characterize a discontinuous phase transition between two phases of the same constituent such as ice. The plot is drawn between 1/T vs ln P.
This equation can be expressed as follows:
ln(P2/P1) = (-ΔHvap/ R)*((1/T2) - (1/T1))
Where T1 is initial temperature, in our case it is normal boiling point = 84oC = 357 K
T2 is final temperature, in our case it is 36oC = 309 K
We know that at normal boiling point the vapor pressure of the substance become equal to the atmospheric pressure = 1 atm.
So P1 = 1 atm. according to our approach to the question.
Now enthalpy of vaporization is given = 22.1 kJ = 22100 J
Now put it in Clausius Clapeyron equation and we will get
ln(P2/ 1 atm.) = (-22100 J / 8.314 J/K-mole)*((1/309 K) - (1/357 K))
P2 /0.317 atm=0.317 x 760 torr = 241 torr
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(T/F) reactive oxygen intermediates and reactive nitrogen intermediates produced by phagocytic cells are effective in killing invading microorganisms
The statement 'reactive oxygen intermediates and reactive nitrogen intermediates produced by phagocytic cells are effective in killing invading microorganisms' is true.
Phagocytic cells are the kind of cells that consume or destroy microorganisms by producing substances that are harmful to them, according to the study of biology.
The phagocytic cells produce oxygen and nitrogen intermediates, and these intermediates are reactive enough to bind to the chemicals in the microbe and inhibit their function. The microorganism dies when its activities are impeded to the point where it is unable to carry out the fundamental functions of life. Thus, the above statement is accurate.
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1. When NaCl are diolved in water, the freezing point i found to be - 0. 26°C. What i the omolarity for thi olution?
The K for water i 1. 86
The freezing point of water after NaCl has been dissolved in it is determined to be - 0.26°C. This solution has a 0.02 mol molarity.
The molality is the proportion of solute, in your case sodium chloride, NaCl, to solvent, in this case water, expressed as the number of moles per kilogram.
Utilizing the substance's molar mass will allow you to determine how many moles of sodium chloride are present in the sample. 25g = 1 mole of NaCl; 58.44g = 0.42 moles of NaCl
You then understand that you are dissolving many moles of sodium chloride in 20 kg of water.
To determine how many moles of solute are present in 1 kilogram of water, utilize the composition of this solution.
0.428 moles of NaCl per kilogram of water. 20 kg water
= 0.0214 moles of sodium chloride
= 0.02 mol
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calculate the wavelength (in nanometers) of a photon emitted by a hydrogen atom when its electron drops from the n
As a result, the photon's wavelength (measured in nanometers) is equal to 1874 nm when the hydrogen atom's electron switches from the n = 4 state to the n = 3 state.
The electromagnetic force is carried by a photon, a basic particle that is a quantum of the electromagnetic field and includes electromagnetic radiation like light and radio waves. Due to their lack of mass, photons always travel at the speed of light in a vacuum, which is 299792458 m/s (or 186,282 mi/s). The photon is a member of the boson family. According to Planck, a material object's energy should be thought of as consisting of an integer number of discrete, equal-sized pieces. Einstein proposed that light itself may explain the photoelectric effect.
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what mass of sodium sulfate is required to form 250. ml of a solution in which the concentration of sodium ions is 0.183 m? provide answer in grams to 3 significant figures.
The mass of sodium sulfate required to form 250mL of a solution in which the concentration of sodium ion is 0.183M is 6.53 grams.
How to calculate mass?The mass of a substance can be calculated by multiplying the number of moles in the substance by its molar mass as follows:
Mass = no of moles × molar mass
However, according to this question, sodium sulfate is has a solution with volume 250mL with a concentration of sodium ions of 0.183M. The no of moles must first be calculated as follows:
moles = 0.183 × 0.250 = 0.046moles
Mass of sodium sulfate = 0.046 × 142.04 g/mol = 6.53 grams.
Therefore, 6.53 grams is the mass of the sodium sulfate solution.
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The mass of sodium sulfate required to form 250 mL of solution in which the concentration of sodium ions is 0.183 would be 3.25 grams.
Stoichiometric problemSodium sulfate is made up of sodium and sulfate ions according to the following equation:
[tex]Na_2SO_4 --- > 2Na^+ + SO_4^2^-[/tex]
From the equation above, a mole of sodium sulfate is made from 2 moles of sodium ions and 1 mole of sulfate ions.
Recall that: mole = molarity x volume
The mole of 0.183 M sodium ion in 250 mL os solution would be:
0.250 x 0.183 = 0.04575 mol
The equivalent mole of sodium sulfate would be:
0.04575/2 = 0.022875 mol
Recall that: mass = mole x molar mass
The molar mass of sodium sulfate is 142.04 g/mol
Mass of 0.022875 mol sodium sulfate = 0.022875 x 142.04
= 3.249165 grams
3.249165 grams to 3 significant figures = 3.25 grams.
Thus, the mass of sodium sulfate required would be 3.25 grams.
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A factory uses nitric (V) acid and ammonia gas in the preparation ofa fertilizer. If the daily production of the fertilizer is 4800kg; calculate the mass of ammonia gas used in kg. N=14.0; 0= 16.0; H=1.0)
The mass of ammonia gas used in kg would be 1.02 kg..
Stoichiometric problemNitric (V) acid and ammonia gas react to form fertilizer according to the following balanced chemical equation:
[tex]HNO_3 + NH_3 -- > NH_4NO_3[/tex]
From the equation, the ratio of the ammonium nitrate produced to the ammonia gas used is 1:1.
The molar mass of [tex]NH_4NO_3[/tex] = 14 + 4 + 14 + 48 = 80 g/mol
Mole of 4800 kg [tex]NH_4NO_3[/tex] = 4800/80 = 60 mol
Thus, the equivalent amount of ammonia that needs to react will also be 60 mol.
Molar mass of amonnia = 14 + 3 = 17 g/mol
Mass of 60 mol ammonia = 60 x 17
= 1020 grams
1020 grams = 1020/1000
= 1.02 kg
In other words, the mass of ammonia gas used would be 1.02 kg.
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Tin (II) oxide is placed into a bottle of hydrogen gas and a reaction occurs where metallic tin and water form:
Skeleton Equation:
Balanced Equation:
The skeleton equation of the reaction of Tin oxide and hydrogen:
[tex]SnO_2 + H_2\longrightarrow Sn + H_2O[/tex]
Balanced equation:
[tex]SnO_2 + 2H_2\longrightarrow Sn + 2H_2O[/tex]
What happened in the reaction of tin and water?Tin (Sn) can be defined as an unreactive metal. When tin dioxide and hydrogen gas react with each other, metallic tin and water are formed.
Sn is not very reactive in comparison with the other elements in its own group, it is more reactive than Ge, which lies just above it in the group. It is unaffected by water or air at room temperature. Sn is anti-corrosive and therefore applied as a coating to protect metals.
When tin dioxide (SnO₂) is placed into a bottle of hydrogen gas. The balanced chemical equation for the chemical reaction is as follows:
[tex]SnO_2 + 2H_2\longrightarrow Sn + 2H_2O[/tex]
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arrange the following isoelectronic series in order of decreasing radius: na+, o2−, f−, al3+, mg2+.
Isoelectronic sequence, from smallest to largest radius: Na+, O2, F, Al3+, Mg2+. The ionic radii of isoelectronic species increase as the magnitudes of nuclear charge decrease.
'what is ionic radii?'
The ionic radius is the distance from an ions nucleus that it can influence its electron cloud.
Ions are produced when an atom gets or loses electrons. When an electron is lost, an atom becomes a cation, and when an electron is acquired, an anion. The ionic radius is the distance between an ion's nucleus and its outermost shell.
The atomic size of a cation will be less than that of its parent atom. An ion's size is often larger than that of its parent atom.
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According to Markovnikov's rule, the hydrogen in HOH (water) adds to the carbon in the double bond A) attached to the end carbon. B) that has the smaller number of hydrogen atoms attached. C) that has greater number of H atoms attached. D) that has smaller number of C-atoms attached. E) that has the greater number of carbon atoms attached.
As per Markovnikov's rule, the hydrogen in HOH (water) adds to the carbon in the double bond (C): that has a greater number of H atoms attached.
Markovnikov's law states that when an asymmetrical reagent is added to an asymmetrical alkene, the negative half of the reagent is attached to the carbon atom containing fewer hydrogen atoms. To put it simply, Markovnikov's rule states that hydrogen is added to the carbon with the greater number of hydrogens and the halide is added to the carbon with the least hydrogens.
An example of a reaction that observes Markovnikov's rule is that in HOH, hydrogen attaches itself to the carbon having more hydrogen substituents.
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What are the function of the cytokinesis hormone in plant's. Choose the correct answer
A ) ! ck jd pyk v zc !
B ) ! ck jd pyk v zc !
These are some of the important functions of the cytokinesis hormone in plants :-
Cytokinesis is a group of growth regulators that is found in plants. It helps in performing cell divison of plant roots, and shoot system. It also helps in promoting the cell's growth, development, flowering, and seed formation.
It helps in the protein production which is important for mitosis. It provides resistance against certain diseases causing bacteria in crops. It mainly contains Nitrogen, Hydrogen, and a few atoms of oxygen in its structure.
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The options for the function of cytokinesis should be:
(A) performing cell division in plant roots
(B) shoot system
(C) promoting the cell’s growth, development
(D) All of these
Answer - (D) All of these
Which option is a measure of the average kinetic energy of the particles in a substance? (1 point)
O thermal energy
O heat
O temperature
O phase
Answer:
Temperature <3
Explanation:
Since it's use to measure kinetic energy, have a nice day! :)
the half-life of cesium-137 is 30 years. suppose we have a 70-mg sample. (a) find the mass that remains after t years.
70/ 2(t/30) mg is the mass that remains after t years, the half-life of cesium-137 is 30 years. suppose we have a 70-mg sample.
Now we have to calculate the mass that remains after 't' years.
As we are given that,
a o= 70 mg
t 1/2= 30 years
Now put all the given values in formula , we get:
a=a0/2(t/t/2)
a= 70/2(t/30) mg
The delicate, golden-colored metal caesium is immediately attacked by air and reacts violently with water. As a drilling fluid, caesium compounds are most frequently used. Additionally, they are employed to produce special optical glass, as a catalytic promoter, in vacuum tubes, and radiation detection apparatus. The universal time standard is also a result of cesium isotopes. Because of this, they are utilised in atomic clocks for cell phone networks, the internet, GPS, and aviation guiding systems.
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Which formula represents a polysaccharide that consists of five monosaccharides joined together by dehydration synthesis? A C6H12O6 B. CaOH.C 5C6H12O6 D. C30H52O26
The formula for a polysaccharide that consists of five monosaccharides joined together by dehydration synthesis is D. C30H52O26.
Polysaccharides are complex carbohydrates made up of long chains of monosaccharides, or simple sugars, linked together by glycosidic bonds. Dehydration synthesis, also known as condensation, is a chemical reaction in which two molecules are joined together by the loss of a water molecule, resulting in the formation of a covalent bond.
The formula C30H52O26 represents a polysaccharide that consists of five monosaccharides with the formula C6H12O6, which is the formula for glucose. When monosaccharides are joined together through dehydration synthesis, the resulting polysaccharide has a formula that is a multiple of the monosaccharide formula. In this case, the polysaccharide consists of five monosaccharides, so its formula is 5 times the formula for a single monosaccharide, or 5 x C6H12O6 = C30H52O26.
A. C6H12O6 is the formula for a single monosaccharide, such as glucose.
B. CaOH.C is not a valid chemical formula.
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The formula for a polysaccharide that consists of five monosaccharides joined together by dehydration synthesis is D. C30H52O26.
Polysaccharides are complex carbohydrates made up of long chains of monosaccharides, or simple sugars, linked together by glycosidic bonds. Dehydration synthesis, also known as condensation, is a chemical reaction in which two molecules are joined together by the loss of a water molecule, resulting in the formation of a covalent bond.
The formula C30H52O26 represents a polysaccharide that consists of five monosaccharides with the formula C6H12O6, which is the formula for glucose. When monosaccharides are joined together through dehydration synthesis, the resulting polysaccharide has a formula that is a multiple of the monosaccharide formula. In this case, the polysaccharide consists of five monosaccharides, so its formula is 5 times the formula for a single monosaccharide, or 5 x C6H12O6 = C30H52O26.
A. C6H12O6 is the formula for a single monosaccharide, such as glucose.
B. CaOH.C is not a valid chemical formula.
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what is the wavelength in nm of the photon emitted when the electron in the h atom drops from n 3 to the n 2 energy level?
Wavelength is the space among equal points (adjoining crests) withinside the adjoining cycles of a waveform sign propagated in area or alongside a wire. The wavelength is 656nm for the hydrogen.
In the photon electricity is inversely proportional to the wavelength of the electromagnetic wave. The shorter the wavelength, the greater lively is the photon, the longer the wavelength, the much less lively is the photon. Photons may be created and destroyed whilst maintaining electricity and momentum.
1/lambda = 109678(0.139) = 15233c * m ^ - 11/lambda = 109678(1/(2 ^ 2) - 1/(3 ^ 2)) 1/lambda = 109678(1/(n_ ^ 2) - 1/(n_ ^ 2))lambda = 6.56 * 10 ^ - 5 * cm = 656nm Hence, the wavelength of the emitted radiation is 656nm.Read more about photon:
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when 36.8 l of carbon monoxide reascvts with 4.9 l of oxygen gas at stp, what is the quantity of heat released to the surroundings
The amount of heat released is 105.41 kJ which is calculated by determining the limiting reactant.
The complete chemical reaction is:
2CO(g)+O2(g)---> 2CO2(g)
Volume of CO= 36.8 L
Mole of CO= 1/22.4 Lx 36.8 L=1.6428 moles
Volume of O2= 4.9 L
Mole of O2=1/22.4 Lx 4.9 L=0.2187 moles
The formation of products is dependent on the number of reactants. The reactant that is consumed first is known as the limiting reactant, when this reactant is consumed completely, then there will be no more formation of products.
The limiting reactant is found out by dividing with stoichiometry coefficients.
CO= 1.6428/2=0.8214
O2=0.2187/1=0.2187
Therefore, the limiting reactant is O2.
If 1 moles of O2 produce 482 kJ heat.
Then, 0.2187 of O2 will produce 4.82x0.2187=105.41 kJ heat.
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determine the volume in ml of 0.585 m hno3(aq) needed to reach the half-equivalence (stoichiometric) point in the titration of 39.29 ml of 0.644 m ch3nh2(aq)(aq). the kb of methylamine is 3.6 x 10-4.
Molarity x volume = 0.585 M x 39.29 mL = 22.984 mmol
At half equivalence point, half of base is neutralized.
Amount of methylamine neutralized: 22.984 /2 = 11.492 mmol
Volume = moles/ molarity = 11.492mmol/0.644M = 17.84mL
We divide the total number of moles of solute by the sum of the solution's liters to determine the molarity of the solution. A chemical species' concentration in a solution, specifically the volume of a solute per unit volume of solution, is measured by its molar concentration. The number of moles per liter is the most often used unit for molarity in chemistry.
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When 34.5 g of KClO3 decompose, how many grams of oxygen are produced?
(answer before Dec 12 preferred- )
Answer:
52.25 grams of oxygen are produced.
Explanation:
When 34.5 g of potassium chlorate (KClO3) decomposes, it produces oxygen gas according to the following chemical equation:
2 KClO3 -> 2 KCl + 3 O2
This means that for every 2 grams of potassium chlorate that decomposes, 3 grams of oxygen gas are produced. In the case of 34.5 grams of potassium chlorate, this would produce 3 * 34.5/2 = 52.25 grams of oxygen. Therefore, when 34.5 g of KClO3 decomposes, 52.25 grams of oxygen are produced.
Which of the following compounds is NOT ionic?
O CaCl₂
O CO₂
O (NH4)20
O Nal
Among the given compounds, CO₂ is a compound that is not ionic.
In this question, we have been given four compounds - CaCl₂, CO₂, (NH₄)₂O, and NaI and among these four compounds, we have to tell which compound is not ionic.
A compound can be ionic or covalent. And the compound which is not ionic is also called a covalent compound.
So let us comment on each compound one by one.
CaCl₂ - It is an ionic compound because it is a compound formed between a metal and a non-metal. As a general rule, any compound formed between a metal and a nonmetal is called an ionic compound and a compound between a nonmetal and a nonmetal is called a covalent compound.
(NH₄)₂O - Though this is a compound containing no metallic element, it is still an ionic compound. NH₄⁺ is an ion, though still a nonmetal. We should remember that NH₄ compounds are exceptions to this rule. All compounds of NH₄ are actually ionic. Hence (NH₄)₂O is an ionic compound.
NaI - It is again a compound made of a metal and a nonmetal. Hence, according to the rule stated above, it is an ionic compound.
CO₂ - It is a compound made of a nonmetal and a nonmetal. Therefore, it is a covalent compound
Hence, among the above-given compounds, CO₂ is a covalent compound.
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which compounds are responsible for the bitter flavor in coffee? catechin caffeine chlorogenic acids theaflavins
The "chlorogenic acids" that give coffee its bitter flavor are these substances. responsible for coffee's harsh taste
How healthy is coffee?
A proper nutrition may for the majority of folks incorporate moderate coffee consumption. Hu found a link between drinking 2 to 5 cups of coffee per day and a lower risk of gynecological, type 2 diabetes, heart disease, as well as liver illness.
The healthiest coffee is which one?
Black, freshly prepared cappuccino is the best option. One cup has very little calories, carbohydrates, or fat, and very little salt. Niacin, potassium, and magnesium are among the micronutrients included in black cappuccino.
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calculate the ph for each of the cases in the titration of 50.0 ml of 0.190 m hclo(aq) with 0.190 m koh(aq)
The ph for each of the cases in the titration of 50.0 ml of 0.190 m hclo(aq) with 0.190 m koh(aq) is 10.1878.
Case 1 when 0.0 mL of KOH is added Ph is 4.0596
Case 2 when 25.0 mL of KOH is added Ph is 7.398
Case 3 when 35.0 mL of KOH is added Ph is 7.766
Case 4 when 50.0 mL of KOH is added Ph is 10.1878
Case 5 when 60.0 mL of KOH is added Ph is 12.2374
Calculation :
1) .when 0.0 mL of KOH is added
HClO dissociates as:
HClO -----> H+ + ClO-
0.19 0 0
0.19-x x x
Ka = [H+][ClO-]/[HClO]
Ka = x*x/(c-x)
Assuming x can be ignored as compared to c
So, above expression becomes
Ka = x*x/(c)
so, x = sqrt (Ka*c)
x = sqrt ((4*10^-8)*0.19) = 8.718*10^-5
since c is much greater than x, our assumption is correct
so, x = 8.718*10^-5 M
use
pH = -log [H+]
= -log (8.718*10^-5)
= 4.0596
2)when 25.0 mL of KOH is added
Given:
M(HClO) = 0.19 M
V(HClO) = 50 mL
M(KOH) = 0.19 M
V(KOH) = 25 mL
mol(HClO) = M(HClO) * V(HClO)
mol(HClO) = 0.19 M * 50 mL = 9.5 mmol
mol(KOH) = M(KOH) * V(KOH)
mol(KOH) = 0.19 M * 25 mL = 4.75 mmol
We have:
mol(HClO) = 9.5 mmol
mol(KOH) = 4.75 mmol
4.75 mmol of both will react
excess HClO remaining = 4.75 mmol
Volume of Solution = 50 + 25 = 75 mL
[HClO] = 4.75 mmol/75 mL = 0.0633M
[ClO-] = 4.75/75 = 0.0633M
They form acidic buffer
acid is HClO
conjugate base is ClO-
Ka = 4*10^-8
pKa = - log (Ka)
= - log(4*10^-8)
= 7.398
use:
pH = pKa + log {[conjugate base]/[acid]}
= 7.398+ log {6.333*10^-2/6.333*10^-2}
= 7.398
3)when 35.0 mL of KOH is added
Given:
M(HClO) = 0.19 M
V(HClO) = 50 mL
M(KOH) = 0.19 M
V(KOH) = 35 mL
mol(HClO) = M(HClO) * V(HClO)
mol(HClO) = 0.19 M * 50 mL = 9.5 mmol
mol(KOH) = M(KOH) * V(KOH)
mol(KOH) = 0.19 M * 35 mL = 6.65 mmol
We have:
mol(HClO) = 9.5 mmol
mol(KOH) = 6.65 mmol
6.65 mmol of both will react
excess HClO remaining = 2.85 mmol
Volume of Solution = 50 + 35 = 85 mL
[HClO] = 2.85 mmol/85 mL = 0.0335M
[ClO-] = 6.65/85 = 0.0782M
They form acidic buffer
acid is HClO
conjugate base is ClO-
a = 4*10^-8
pKa = - log (Ka)
= - log(4*10^-8)= 7.398
use:
pH = pKa + log {[conjugate base]/[acid]}
= 7.398+ log {7.824*10^-2/3.353*10^-2}
= 7.766
4)when 50.0 mL of KOH is added
Given:
M(HClO) = 0.19 M
V(HClO) = 50 mL
M(KOH) = 0.19 M
V(KOH) = 50 mL
mol(HClO) = M(HClO) * V(HClO)
mol(HClO) = 0.19 M * 50 mL = 9.5 mmol
mol(KOH) = M(KOH) * V(KOH)
mol(KOH) = 0.19 M * 50 mL = 9.5 mmol
We have:
mol(HClO) = 9.5 mmol
mol(KOH) = 9.5 mmol
9.5 mmol of both will react to form ClO- and H2O
ClO- here is strong base
ClO- formed = 9.5 mmol
Volume of Solution = 50 + 50 = 100 mL
Kb of ClO- = Kw/Ka = 1*10^-14/4*10^-8 = 2.5*10^-7
concentration ofClO-,c = 9.5 mmol/100 mL = 0.095M
ClO- dissociates as
ClO- + H2O -----> HClO + OH-
0.095 0 0
0.095-x x x
Kb = [HClO][OH-]/[ClO-]
Kb = x*x/(c-x)
Assuming x can be ignored as compared to c
So, above expression becomes
Kb = x*x/(c)
so, x = sqrt (Kb*c)
x = sqrt ((2.5*10^-7)*9.5*10^-2) = 1.541*10^-4
since c is much greater than x, our assumption is correct
so, x = 1.541*10^-4 M
[OH-] = x = 1.541*10^-4 M
use:
pOH = -log [OH-]
= -log (1.541*10^-4)
= 3.8122
use:
PH = 14 - pOH
= 14 - 3.8122
= 10.1878
5)when 60.0 mL of KOH is added
Given:
M(HClO) = 0.19 M
V(HClO) = 50 mL
M(KOH) = 0.19 M
V(KOH) = 60 mL
mol(HClO) = M(HClO) * V(HClO)
mol(HClO) = 0.19 M * 50 mL = 9.5 mmol
mol(KOH) = M(KOH) * V(KOH)
mol(KOH) = 0.19 M * 60 mL = 11.4 mmol
We have:
mol(HClO) = 9.5 mmol
mol(KOH) = 11.4 mmol
9.5 mmol of both will react
excess KOH remaining = 1.9 mmol
Volume of Solution = 50 + 60 = 110 mL
[OH-] = 1.9 mmol/110 mL = 0.0173 M
use:
pOH = -log [OH-]
= -log (1.727*10^-2)
= 1.7626
use:
PH = 14 - pOH
= 14 - 1.7626
= 12.2374
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FILL IN THE BLANK. an electron cannot have the quantum numbers n = ________, l = ________, ml = ________.
An electron will not posses the quantum numbers n = 1, l = 1, ml = 1.
Quantum numbers may be the number sequence utilized to express the location and velocity of an electron within an atom. The primary, azimuthal, magnetic, as well as spin quantum numbers are just the four types of quantum numbers.
Wolfgang Pauli established the Pauli Exclusion Principle in 1926, which states that each electron has a special combination of quantum numbers. In other words, the values of n, l, ml, and ms cannot be like for pair of electrons.
-- The given question is incomplete, the complete question is:
"An electron cannot have the quantum numbers__"n = ________, l = ________, ml = ________.
A) 2, 0, 0
B) 2, 1, -1
C) 3, 1, -1
D) 1, 1, 1
E) 3, 2, 1" --
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silver has a face-centered cubic unit cell. how many atoms of ag are present in each unit cell?
Answer:
Explanation:
as we know in a face-centered unit each atom give1/2 a portion at the face
and fully atom involvement at center therefore
1/2( total face of cube )+ 1(centre)
1/2 ×6 + 1
3+ 1
4 atoms per cell