Answer:
M(OH)2 Ksp = 2.64 x 10-3
Explanation:
Recall that for M(OH)2, its dissolution in water gives;
M(OH)2(s) ----> M^2+(aq) + 2OH^-(aq)
Ksp= x × (2x)^2
Ksp= 4x^3
a)
Ksp= 4.25 x 10^-6
Ksp= 4x^3
x= 3√Ksp/4
x= 3√4.25 x 10^-6/4
x= 1.02 ×10^-2 moldm-3
For 2 OH^- = 2 × 1.02 ×10^-2 moldm-3 = 2.04 ×10^-2 moldm-3
b)
Ksp= 7.39 x 10^-4
Ksp= 4x^3
x= 3√Ksp/4
x= 3√7.39 x 10^-4/4
x= 5.7 ×10^-2 moldm-3
For 2 OH^- = 2 × 5.7 ×10^-2 moldm-3= 11.4 ×10^-2 moldm-3
c)
Ksp= 2.64 x 10^-3
Ksp= 4x^3
x= 3√Ksp/4
x= 3√2.64 x 10^-3/4
x= 8.7 ×10^-2 moldm-3
For 2 OH^- = 2 × 8.7 ×10^-2 moldm-3 = 17.4 ×10^-2 moldm-3
d)
Ksp= 8.52 x 10^-8
Ksp= 4x^3
x= 3√Ksp/4
x= 3√8.52 x 10^-8/4
x= 2.77 ×10^-3 moldm-3
For 2 OH^- = 2 × 2.77 ×10^-3 moldm-3 = 5.54 ×10^-3 moldm-3
Hence, M(OH)2 Ksp = 2.64 x 10-3 has the highest [OH- ].
How will temperature affect the spontaneity of a reaction with positive H and S?
A. It will be spontaneous only at T = H/S.
B.Changing the temperature will not affect spontaneity.
C.A low temperature will make it spontaneous.
D.A high temperature will make it spontaneous.
Answer:
D.A high temperature will make it spontaneous.
Explanation:
we know that
Δ G = Δ H - TΔS
For spontaneous reaction
Δ G should be negative . If Δ G = 0
Δ H = TΔS
T = Δ H / Δ S
At temperature above this T , Δ G becomes negative if Δ S and ΔH are positive .
So at a high temperature will make it spontaneous.
Answer:
D. A high temperature will make it spontaneous.
Explanation:
A P E X
FeCl2(aq) + Na2CO3(aq) FeCO3(s) + 2NaCl(aq) What are the spectator ions in this equation?
Answer:
Chloride (Cl⁻) and sodium (Na⁺) ions.
Explanation:
Hello,
In this case, since the aqueous species are actually dissociated when reacting and the solid species (ferric carbonate) remains undissolved, we can modify the given reaction as follows:
[tex]FeCl_2(aq) + Na_2CO_3(aq) \rightarrow FeCO_3(s) + 2NaCl(aq)[/tex]
In such a way, dissociating the aqueous species we obtain:
[tex]Fe^{2+}(aq)+2Cl^-(aq) + 2Na^+(aq)+CO_3^{2-}(aq) \rightarrow FeCO_3(s) + 2Na^+(aq)+2Cl^-(aq)[/tex]
It means that the net ionic equation is:
[tex]Fe^{2+}(aq)+CO_3^{2-}(aq) \rightarrow FeCO_3(s)[/tex]
Therefore, the spectator ions are those were cancelled out, chloride (Cl⁻) and sodium (Na⁺).
Best regards.
How many lbs. of O2 are required to fully convert 1-lb of glucose (C6H12O6) to carbon dioxide and water
Answer:
The correct answer is : 1.07 lbs
Explanation:
solution:
molar mass glucose (C6H12O6) = 180 g/mol
molar mass of oxygen molecule (O2) = 32 g/mol (as we know molar mass of O = 16 g/mol)
the balanced reaction of conversion of water and oxygen to glucose is:
[tex]C_{6}H_{12}O_{6} + 6O_{2} \rightarrow 6CO_{2} + 6H_{2}O ...(A)[/tex]
1 mol of C6H12O6 = 6 mol of O2 (from reaction A)
so, 180 g C6H12O6 = 192 g O2
that is, 0.396 lb of C6H12O6 = 0.423 lb of O2 ( 1 g = 0.00220462 lb )
so,
1 lb C6H12O6 =[tex]\frac{1(lb) \times 0.4233 (lb)}{0.3968 (lb)}[/tex] = 1.07 lb O2
therefore, the correct answer is : 1.07 lbs
Select the salts that will undergo hydrolysis.
a. KF
b. NaNO3
c. NH4NO2
d. MgSO4
e. KCN
f. C6H5COONa
g. RbI
h. Na2CO3
i. CaCl2
j. HCOOK
Answer:
- In general, the salt that can make hydrolysis (both ions) is option c (ammonium nitrite).
- Salts that can make hydrolysis (one of the ions) are option a (potassium fluoride), option e (potassium cyanide), option f (sodium benzoate), option h (sodium carbonate) and option k (potassium formiate).
- Surely the neutrals salt are (salts that don't make hydrolysis) option b (sodium nitrate), option d (magnessium sulfate), option g (rubidium iodide) and option i (calcium chloride).
Explanation:
To determine the hydrolysis we have to dissociate the salts, and then we define the conjugate strong bases or acids, that can react to water.
a. KF → K⁺ + F⁻
F⁻ comes from the HF, a weak acid so the anion is the conjugate strong base. F⁻ can make hydrolysis, but the K⁺, can not.
b. NaNO₃ → Na⁺ + NO₃⁻
Boths are conjugate weak acid and base, this salt is neutral. So they cannot do hydrolysis.
c. NH₄NO₂ → NH₄⁺ + NO₂⁻
Both ions can make hydrolysis to water, because the are conjugate strong base and acid.
The ammonium gives ammonium again:
NH₄⁺ + H₂O ⇄ NH₃ + H₃O⁺ Ka
The nitrite gives nitrose acid, again
NO₂⁻ + H₂O ⇄ HNO₂ + OH⁻ Kb
d. MgSO₄ → Mg²⁺ + SO₄⁻²
This is a neutral salt. Boths are conjugate weak acid and base, that's why they can not make hydrolysis.
e. KCN → K⁺ + CN⁻
As K⁺ comes from a strong base, it can not do hydrolysis.
Then, the cyanide can make hydrolysis because it comes from the HCN (a weak acid), so the ion is the conjugate strong base.
CN⁻ + H₂O ⇄ HCN + OH⁻
f. C₆H₅COONa → C₆H₅COO⁻ + Na⁺
This salt is called sodium benzoate. As Na⁺ comes from a strong base, it can not do hydrolysis. Then, the C₆H₅COO⁻ can make hydrolysis because it comes from the benzoic acid, so the ion is the conjugate strong base.
C₆H₅COO⁻ + H₂O ⇄ C₆H₅COOH + OH⁻ Kb
g. RbI → Rb⁺ + I⁻
This is a neutral salt. Similar case as NaCl. Both are conjugate weak acid and base, that's why they can not make hydrolysis.
h. Na₂CO₃ → 2Na⁺ + CO₃⁻²
The one that can make hydrolysis in this case, is the carbonate anion.
CO₃⁻² + H₂O ⇄ HCO₃⁻ + OH⁻
Carbonate comes from the carbonic acid, a dyprotic weak one.
i. CaCl₂ → Ca²⁺ + 2Cl⁻
This is a neutral salt. Similar case as NaCl. Both are conjugate weak acid and base, that's why they can not make hydrolysis.
j. HCOOK → HCOO⁻ + K⁺
This is the potassium formiate. K⁺ comes from KOH, a strong base. It don't make hydrolysis, while the HCOO⁻ can do the hydrolysis in water.
When the formiate react, we can produce formic acid. Formiate is the conjugate strong base, of a weak acid.
HCOO⁻ + H₂O ⇄ HCOOH + OH⁻
Temperature is a measure of the amount of heat in a substance. 1) True 2) False
Answer:
False
Explanation:
Temperature is the measure of the amount of kinetic energy in a substance.
It is commonly assumed that temperature measures the amount of heat, because it is commonly associated with the weather or checking for fevers.
However, temperature is truly a measure of the average kinetic energy of a substance.
Answer:
Temperature is the measure of average kinetic energy in a substance.but heat is also a form of kinetic energy so i think its also true to say that temperature is a measure of heat in a substance.
Explanation:
are any substance made up of matter and can be natural or man-made.
Answer:
Yes.
Explanation:
Substances are made up of matter or matter are made up of tiny molecules or atoms that occur naturally or some are synthetic or man made.
All matter are made up of substances called elements and each elements have its own physical and chemical properties and cannot be broken easily by ordinary chemical reactions.
Of all the 118 elements only 92 occur naturally and 26 are man made or synthetic which are made in the laboratories.
1.An aqueous solution of 0.975 M hydrochloric acid, HCl, has a density of 1.02 g/mL. The percent by mass of HCl in the solution is ___ %.
2.An aqueous solution of 1.29 M ethanol, CH3CH2OH, has a density of 0.988 g/mL. The percent by mass of CH3CH2OH in the solution is ___%.
3.An aqueous solution is 40.0% by mass silver nitrate, AgNO3, and has a density of 1.47 g/mL. The molarity of silver nitrate in the solution is ___M.
Answer:
The percent mass of HCl in the solution is 3.48 %
The percent mass of ethanol in the solution is 6.01 %
The molarity of silver nitrate in the solution is 3.46 M
Explanation:
Percent by mass = mass of solute/100 g of solutionDensity always referrs to solution data.
1.02 g/mL = 100 g / volume of solution
Volume of solution = 98.04 mL
Molarity = moles of solute in 1L of solution (or mmoles of solute in 1mL)
M . 98.04 mL = mmoles of solute → 0.975 M . 98.04 mL = 95.59 mmoles
mmoles . PM (mg / mmol) = mg → 95.59 mmol . 36.45 mg/mmol = 3484 mg.
We convert data to g → 3484 mg . 1g/ 1000 mg = 3.48 g
The percent mass of HCl in the solution is 3.48 %
Percent by mass = mass of solute/100 g of solutionDensity always referrs to solution data.
0.988 g/mL = 100 g / volume of solution
Volume of solution = 101.21 mL
Molarity = moles of solute in 1L of solution (or mmoles of solute in 1mL)
M . 101.21 mL = mmoles of solute → 1.29 M . 101.21 mL = 130.6 mmoles
mmoles . PM (mg / mmol) = mg → 130.6 mmol . 46.07 mg/mmol = 6015 mg.
We convert data to g → 6015 mg . 1g/ 1000 mg = 6.01 g
The percent mass of ethanol in the solution is 6.01 %
Percent by mass = mass of solute/100 g of solutionDensity always referrs to solution data.
1.47 g/mL = 100 g / volume of solution
Volume of solution = 68.03 mL
Molarity = moles of solute in 1L of solution (or mmoles of solute in 1mL)
40 g = 40000 mg
mg / PM (mg / mmol) = mmol → 40000 mg / 169.87 mg/mmol
= 235.4 mmoles
mmoles / mL = Molarity → 235.4 mmol / 68.03 mL = 3.46 M
A number should be rounded up if________? it is the first digit, the number after it is between 0 and 4, the number after is between 5 and 9, it is the last digit
Answer:
a number should be rounded up it is 5 or higher
What are scientific models used for? Give an example of each of the follwoing types of models: idea, physical, computer
Answer:
Scientific models are used to explain phenomena that can not be experience directly and it is also used for prediction.
Explanation:
An example of idea model is the Eistein equation. An idea model shows how things interact together to produce a particular result.
An example of physical model is the solar system.
Computer model is used to predict long term events and an example of this is computer simulations.
At 700 K, the reaction 2SO 2(g) + O 2(g) 2SO 3(g) has the equilibrium constant K c = 4.3 × 10 6, and the following concentrations are present: [SO 2] = 0.010 M; [SO 3] = 10. M; [O 2] = 0.010 M. Which of the following is true based on the above?
A. Qc < Kc, the reaction proceeds from right to left to reach equilibrium
B. Qc < Kc, the reaction proceeds from left to right to reach equilibrium
C. Qc > Kc, the reaction proceeds from right to left to reach equilibrium
D. Qc > Kc, the reaction proceeds from left to right to reach equilibrium
E. Qc = Kc, the reaction is currently at equilibriums
Answer:
The correct answer is "C. Qc > Kc, the reaction proceeds from right to left to reach equilibrium"
Explanation:
The reaction quotient Qc is a measure of the relative amount of products and reactants present in a reaction at a given time.
Being:
aA + bB ⇔ cC + dD
where a, b, c and d are the stoichiometric coefficients of the balanced equation, the coefficient Q is calculated as:
[tex]Qc=\frac{[C]^{c}*[D]^{d} }{[A]^{a} *[B]^{b} }[/tex]
If Qc <Kc there is less concentration of products than in equilibrium, with which the reaction will evolve to the right to increase the concentration of products.
If Qc> Kc, it is possible to affirm that the reaction will evolve to the left since in this case the direct reaction predominates and there will be more product present than what is obtained in equilibrium. Therefore, this product is used to promote the reverse reaction and achieve equilibrium. Then the system will evolve to the left to increase the concentration of reagents.
If Qc = Kc, it means that the reaction is in equilibrium.
In the case of the reaction:
2 SO₂ (g) + O₂ (g) ⇔ 2 SO₃(g)
the value of the constant Qc is calculated as:
[tex]Qc=\frac{[SO_{3} ]^{2} }{[SO_{2} ]^{2} *[O_{2} ]}[/tex]
Being:
[SO₂] = 0.010 M [SO₃] = 10 M [O₂] = 0.010 Mand replacing:
[tex]Qc=\frac{10^{2} }{0.010^{2} *0.010}[/tex]
you get:
Qc=100,000,000=1*10⁸
Being Kc=4.3*10⁶, then Qc>Kc and the reaction proceeds from right to left to reach equilibrium.
So the correct answer is "C. Qc > Kc, the reaction proceeds from right to left to reach equilibrium"
Which of the following solutions will have the lowest freezing point?
a. 0.010 m Li2SO4
b. 0.015 m MgCl2
c. 0.035 m CH3CH2CH2OH
d. 0.010 m NaCl
Answer:
0.035 m CH3CH2CH2OH
Explanation:
We know that freezing point is a coligative property hence it depends on the number of solute particles present.
Covalent substances do not break up into ions, hence they do not produce many particles in solution unlike ionic substances. Hence, ionic substances have a far higher freezing point than covalent molecules.
For this reason, 0.035 m CH3CH2CH2OH has the lowest freezing point.
Which direction will the following reaction (in a 5.0 L flask) proceed if the pressure of CO_2(g) is 1.0 atm? CaCO_3(s) rightarrow CaO(s) + C02(g) Kp = 1.9 times 10^-23
a. To the right because Q > K_p
b. To the right because Q < K_p
c. To the left because Q < K_p
d. To the left because Q > K_p
Answer:
d. To the left because Q > K_p
Explanation:
Hello,
In this case, for the given reaction:
[tex]CaCO_3(s) \rightarrow CaO(s) + CO_2(g)[/tex]
The pressure-based equilibrium expression is:
[tex]Kp=p_{CO_2}[/tex]
In such a way, since Kp is given we rather compute the reaction quotient at the specificed pressure of carbon dioxide as shown below:
[tex]Q=p_{CO2}=1.0[/tex]
Therefore, since Q>Kp we can see that there are more products than reactants, which means that the reaction must shift leftwards towards the reactants in order to reestablish equilibrium, thus, answer is d. To the left because Q > Kp.
Regards.
Both hydrogen sulfide (H2S) and ammonia (NH3) have strong, unpleasant odors. Which gas has the higher effusion rate? If you opened a container of each gas in a corner of a large room, which odor would you detect first on the other side of the room? Assume the temperature is constant.
The molar mass of H2S is greater than the molar mass of NH3, making the velocity and effusion rate of NH3 particles faster.
What is Effusion rate?Effusion rate is inversely proportional to molar mass. NH3 will have a higher average molecule velocity, so it will diffuse faster and will reach the other side of the room more quickly.
The concentration gradient, or the rise or fall in concentration from one site to another, the amount of surface area available for diffusion, and the distance the gas particles must travel all affect the diffusion rate.
The effusion of gas molecules into a vacuum through a small hole, as a pinhole in a balloon, is a process that involves movement of gaseous species comparable to diffusion.
Therefore, The molar mass of H2S is greater than the molar mass of NH3, making the velocity and effusion rate of NH3 particles faster.
To learn more about Diffusion, refer to the link:
https://brainly.com/question/20843145
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Express 7,376,000,000 (population of the world) in scientific notation
Answer:
7.376 × 10^9 people
Explanation:
yes
A graduated cylinder contains 4.50 mL of water. After a piece of zinc is dropped into the cylinder, the water level rises to 9.24 mL. What is the volume of the piece of zinc?
Answer: Well, the volume of the copper is (63.4 - 40.0) * mL = 23.4 * mL
Explanation:
Do you agree? The copper displaces the given volume of water.
Now ρ Cu = 8.90 ⋅ g ⋅ c m 3 OR ρ Cu = 8.90 ⋅ g ⋅ m L − 1, i.e. 1 ⋅ m L ≡ 1 ⋅ c m 3
But by definition, ρ density = mass volume
And thus mass = ρ × volume = 8.90 ⋅ g ⋅ m L − 1 × 23.4 ⋅ m L
= 208.3 * G
Which compound is more soluble in an acidic solution than in a neutral solution? a) PbBr2 b) CuCl c) AgI d) BaF2
Answer:
d) BaF2
Explanation:
The compound which is more soluble in an acidic solution than in a neutral solution is shown below:-
First we will compare acidic with Neutral
[tex]acidic \rightarrow H+ ions[/tex]
So,
[tex]PbBr2 \rightarrow Pb+2 + 2Br-[/tex]
[tex]BaF2 \rightarrow Ba+2 + 2F-[/tex]
[tex]AgI \rightarrow Ag+ + I-[/tex]
[tex]CuCl \rightarrow Cu+ + Cl-[/tex]
Now, when we add H+ ions, so it will be
[tex]BaF2 \rightarrow Ba+2 + 2F-[/tex]
[tex]F- + H2O <-> HF + OH-[/tex]
Then it will reduces F-, as BaF2 begin to form more aqueous ions, so, it will rises the solubility
Determine if the following compounds will be soluble or insoluble in water?
a) CrPO4
b) Na2S
c) PbBr2
d) Ag2SO4
e) Ca(ClO3)2
f) K3PO4
Answer:
a) Insoluble
b) Soluble
c) Insoluble
d) Insoluble
e) Soluble
f) Soluble
Explanation:
In the following net ionic equation, identify each reactant as either a Bronsted-Lowry acid or a Bronsted-Lowry base. HCN(aq) H2O(l) CN-(aq) H3O (aq) B-L _____ B-L _____
The formula of the reactant that acts as a proton donor is_______
The formula of the reactant that acts as a proton acceptor is________
Answer:
Explanation:
The definition of acids and bases by Arrhenius Theory was modified and extended by Bronsted-Lowry.
Bronsted-Lowry defined acid as a molecule or ion which donates a proton while a base is a molecule or ions that accepts the proton. This definition can be extended to include acid -base titrations in non-aqueous solutions.
In this theory, the reaction of an acid with a base constitutes a transfer of a proton from the acid to the base.
From the given information:
[tex]\mathsf{HCN _{(aq)} + H_2O_{(l)} \to CN^{-}_{(aq)} + H_3O_{(aq)}}[/tex]
From above:
We will see that HCN releases an H⁺ ion, thus it is a Bronsted-Lowry acid
[tex]H_2O[/tex] accepts the H⁺ ion ,thus it is a Bronsted-Lowry base.
The formula of the reactant that acts as a proton donor is HCN
The formula of the reactant that acts as a proton acceptor is H2O
What is the limiting reactant for the reaction below given that you start with 10.0 grams of Al (molar mass 26.98 g mol-1) and 19.0 grams of O2 (molar mass 32.00 g mol-1)? Equation: 4Al + 3O2 → 2Al2O3
Answer:
Al
Explanation:
4 Al + 3 O₂ → 2 Al₂O₃
You need to figure out which one has the smaller mole ratio. Convert both substances from grams to moles.
(10.0 g Al)/(26.98 g/mol) = 0.3706 mol Al
(19.0 g O₂)/(32.00 g/mol) = 0.5938 mol O₂
Now, use the mole ratios of reactant to product to see which substance produces the least amount of product.
(0.3706 mol Al) × (2 mol Al₂O₃/4 mol Al) = 0.1853 mol Al₂O₃
(0.5938 mol O₂) × (2 mol Al₂O₃/3 mol O₂) = 0.3958 mol Al₂O₃
Since aluminum produces the least amount of product, this is the limiting reagent.
Al is a limiting reagent. A further explanation is below.
Given equation,
[tex]4Al+3O_2 \rightarrow 2Al_2O_3[/tex]So,
4 moles of Al reacts with 3 moles of O₂ to produce 2 moles of Al₂O₃.
Mass of Al = 10 gMolar mass = 26.98 g/molthen,
Number of moles of Al,
= [tex]\frac{10 \ g}{26.98 \ g/mol}[/tex]
= [tex]3.706\times 10^{-1} \ moles[/tex]
Now,
Mass of O₂ = 19 gMolar mass = 32 g/molthen,
Number of moles of O₂,
= [tex]\frac{19 \ g}{32 \ g/mol}[/tex]
= [tex]5.937\times 10^{-1} \ moles[/tex]
Now,
[tex]5.937\times 10^{-1} \ moles[/tex] of O₂ can react with,
= [tex]4\times \frac{5.937\times 10^{-1}}{3}[/tex]
= [tex]7.916\times 10^{-1} \ moles \ of \ Al[/tex]
But there is only [tex]3.706\times 10^{-1}[/tex] moles of Al available.
Thus the above approach is right.
Learn more:
https://brainly.com/question/1983373
How does the solubility of atmospheric carbon dioxide change with variations in pH and salinity?
Answer:
Decreasing pH decreases the solubility; increasing salinity increases the salinity.
Explanation:
Atmospheric carbon dioxide in seawater is involved in the following equilibria:
(i) CO₂(g) ⇌ CO₂(aq)
(ii) CO₂(aq) + H₂O ⇌ H₂CO₃(aq)
(iii) H₂CO₃(aq) + H₂O(l) ⇌ H₃O⁺(aq) + HCO₃⁻(aq)
(iv) HCO₃⁻(aq)+ H₂O(l) ⇌ H₃O⁺(aq) + CO₃²⁻(aq)
1. Effect of pH
Decreasing pH increases [H₃O⁺].
According to Le Châtelier's Principle, the position of equilibrium of (iv) will be pushed to the left.
This, in turn, pushes the positions of equilibrium of (iii), (ii), and (i) to the left.
The net effect is that CO₂ is pushed out of the solution and back into the atmosphere.
Thus, decreasing the pH decreases the solubility of atmospheric CO₂.
2. Effect of salinity
Salinity includes the measurement of all ions in seawater, not just Na⁺ and Cl⁻.
An important ion that contributes to salinity is Ca²⁺.
Ca²⁺ ions are involved in the equilibrium
Ca²⁺(aq) + CO₃²⁻(aq) ⇌ CaCO₃(s).
Thus, increasing the salinity ([Ca²⁺]) removes CO₃²⁻ from the solution and pulls the position of equilibrium of (iv) to the right.
The effect goes back through the chain of equilibria.
The net result is that more atmospheric CO₂(g) dissolves in the seawater to replace the CO₃²⁻ that has been removed.
Increasing the salinity increases the solubility of atmospheric CO₂.
What does a decrease in temperature indicate about the molecules in a sample of liquid water? (3 points) a Decreased chemical energy of the molecules b Decreased kinetic energy of the molecules c Increased chemical energy of the molecules d Increased kinetic energy of the molecules
Answer:
option b is correct
Explanation:
when the temperature of liquid solid and gases increases the kinetic energy of their molecules increases but when the temperature of liquid solid or gases decreases then kinetic energy of the molecule decreases
Answer:
B. Decreased kinetic energy of the molecules
Explanation:
The average kinetic energy of molecules determines the temperature of a substance.
Hotter objects
have faster-moving particles and higher temperatures
Temperature measures the averages because moving particles can absorb/release heat with each collision as heat is converted to kinetic energy and back.
Chemistry V22 flvs 6.01
Determine the pH of a buffer which is a 0.20 M solution of trimethylamine (N(CH3)3) and a 0.40 M solution of trimethylammonium chloride (NH(CH3)3Cl). The Kb of trimethylamine at 25°C is 6.3x10-5.
Answer:
pH of the buffer is 10.10
Explanation:
trimethylamine is a weak base that, in presence with its conjugate base, trimethylammonium ion, produce a buffer.
To determine the pH of the buffer we use H-H equation for weak bases:
pOH = pKb + log [Conjugate acid] / [Weak base]
pKb is -log Kb = 4.20
pOH = 4.20 + log [N(CH₃)₃] / [NH(CH₃)₃]
Replacing the concentrations of the problem:
pOH = 4.20 + log [0.20M] / [0.40M]
pOH = 3.90
As pH = 14 -pOH
pH of the buffer is 10.10
For a voltaic cell consisting of Al(s) in Al(NO3)3(aq) and Cu(s) in Cu(NO3)2(aq), what is Ecell, given [Al3 ]
Answer:
2.0 V
Explanation:
For the oxidation half cell;
Al(s) -------> Al^3+(aq) + 3e.
For reduction half cell;
Cu^2+(aq) +2e ------> Cu(s).
E°cell = E°cathode - E°anode
But;
E°cathode= 0.34 V
E°anode = -1.66 V
E°cell= 0.34 -(-1.66)
E°cell= 2.0 V
1. Determine whether or not the equation below is balanced. If it isn’t balanced, write the balanced form. Also, identify the reactant(s) and product(s) in this equation. Finally, label this as one of the five types of reactions: combination, decomposition, substitution, double replacement, or reversible.
Answer:
- Not balanced.
- Reactants: Zn and HCI .
- Products: ZnCl₂ and H₂.
- Substitution reaction.
Explanation:
Hello,
In this case, for the given reaction:
Zn + HCI → ZnCl₂ + H₂
We can see that it is not balanced due to the fact that at the left side we have one hydrogen atom whereas at the right side two, taking into account the number must be same as well as chlorine. Thus, in order to balance we write:
Zn + 2HCI → ZnCl₂ + H₂
And that is enough. Moreover, we can see that the chemical species at the left side of the equation are the reactants and those at the right side the products, thus we have:
Reactants: Zn and HCI .
Products: ZnCl₂ and H₂.
Finally, since we can see that the chlorine is at the reactants with hydrogen, but at the end with the zinc, and the initial zinc is alone as well as the yielded hydrogen we can infer this is a substitution reaction.
Best regards.
Answer:
The equation isn't balanced because there aren't equal numbers of hydrogen or chlorine atoms on both sides of the equation. To correct this, a coefficient of 2 must be placed in front of HCl on the left-hand side of the equation.
Explanation:
The following molecular equation represents the reaction that occurs when aqueous solutions of silver(I) nitrate and calcium chloride are combined.
2AgNO3 (aq) + CaCl2 (aq)-------- 2AgCl (s) + Ca(NO3)2 (aq)
Write the balanced net ionic equation for the reaction.
Answer:
Ag+(aq) + Cl-(aq) —> AgCl(s)
Explanation:
2AgNO3(aq) + CaCl2(aq) —>2AgCl(s) + Ca(NO3)2(aq)
The balanced net ionic equation for the reaction above can be obtained as follow:
AgNO3(aq) and CaCl2(aq) will dissociate in solution as follow:
AgNO3(aq) —> Ag+(aq) + NO3-(aq)
CaCl2(aq) —> Ca2+(aq) + 2Cl-(aq)
AgNO3(aq) + CaCl2(aq) –>
2Ag+(aq) + 2NO3-(aq) + Ca2+(aq) + 2Cl-(aq) —> 2AgCl(s) + Ca2+(aq) + 2NO3-(aq)
Cancel out the spectator ions i.e Ca2+(aq) and 2NO3- to obtain the net ionic equation.
2Ag+(aq) + 2Cl-(aq) —> 2AgCl(s)
Divide through by 2
Ag+(aq) + Cl-(aq) —> AgCl(s)
The, the net ionic equation is
Ag+(aq) + Cl-(aq) —> AgCl(s)
1. While searching through a an old trunk you found a treasure map that says a treasure chest was burried 27
chains due west of the US Capitol Building. The treasure chest has 50 talents of gold and is buried 3 chains deep
under ground. Through your research you have discovered that 1 talent is 30.2 kg and 1 chain is 20.1 meters. How
many meters from the US Capitol should you dig, and how deep will you have to dig to find the treasure chest?
Answer:
See the answer below
Explanation:
From the illustration;
1 chain = 20.1 meters
1 talent = 30.2 kg
The map says the treasure chest was buried 27 chains due west and 3 chains deep under the ground.
27 x 20.1 = 542.7 meters.
3 x 20.1 = 60.3 meters
This means that one would need to travel 542.7 meters due west from the US Capitol and dig 60.3 meters under the ground in order to locate the treasure chest.
The treasure chest has 50 talents of gold:
50 x 30.2 = 1,510 kg of gold.
What is the diameter of the coin to the nearest
millimeter?
36 mm
37 mm
38 mm
39 mm
Answer:
Explanation:
Diameter in the coin is the distance from side to side.
The numbers in the ruler are showing the centimeters. Each line is a subdivision in ten parts between centimeter and centimeter (Each line is equal to 1mm).
As you can see in the ruler, in the edge of the coin, the ruler is showing 3.8cm
As 1cm = 10mm:
3.8cm * (10mm / 1cm) =
38mm is the diameter of the coin to the nearest milimeter
Answer:
38m
Explanation:
Fill in the [?]:
82 ul = [?]x10^[?] L
Answer:
8.2×10¯⁵ L
Explanation:
82 μL.
We can convert 82 μL to L by doing the following:
To convert from microlitre (μL) to litre(L), we need to know how many microlitre (μL) that makes up a litre (L)
Recall:
1 μL = 1×10¯⁶ L
Therefore,
82 μL = 82 μL × 1×10¯⁶ L/1 μL
82 μL = 8.2×10¯⁵ L
Therefore, 82 μL is equivalent to 8.2×10¯⁵ L
calculate the specific heat of copper if it takes 23 cal to heat a 5.0 g sample from 25 C to 75 C
Answer:
0.384928 J/g°C
Explanation:
The formula for Specific Heat (C)
= q/m × ∆t
Where q = Heat energy required to heat the compound (in joules)
m = mass of the compound (sample)
∆t = Change in temperature
In the question, we are given the following values.
m = 5.0g
∆t = Change in temperature = 75°C - 25°C
= 50°C
q = Heat energy = 23 cal
We have to convert to joules
One calorie is equal to 4.184 joules.
1 Cal = 4.184 joules
23 Cal =
23 × 4.184 joules
= 96.232 joules
Specific Heat (C) of copper
= 96.232 J /(5g × 50°C)
= 96.232J / 250
= 0.384928 J/g°C
Therefore, the Specific Heat of Copper is 0.384928 J/g°C
The number of bonds an atom can form without violating the octet rule is reflected in the number of holes the "ball" for that atom has in the ball-and-stick model set. Based on that information, how many holes would you expect to see in models of atoms for each of the following elements: (4 points total; 1 point per element) a. Carbon (C)
Answer:
four holes
Explanation:
A ball and stick model is a representation of a molecule that can show the number of bonds and sometimes, the stereochemistry of the molecule under study.
The number of holes on present in the ball and stick model for any atom corresponds to the number of bonds that particular atom can form without violating the octet rule.
Carbon is usually tetravalent, it forms four bonds to other atoms. Hence we expect carbon to have four holes.
Answer:
Explanation:
Carbon - Four-hole
Nitrogen - Three-hole
Oxygen - Two-hole
Hydrogyn - Two-hole