Answer:
-36.6 kJ·mol⁻¹
Explanation:
1. Calculate ΔG
[tex]\text{The relationship between $\Delta G^{\circ}$ and K is}\\\Delta G^{\circ} = -RT \ln K[/tex]
T = (250 + 273.15) K = 523.15 K
[tex]\begin{array}{rcl}\Delta G & = & -8.314 \text{ J}\cdot\text{K}^{-1} \text{mol}^{-1} \times \text{523.15 K} \ln (4.5 \times 10^{3}) \\& = & -4349\text{ J}\cdot \text{mol}^{-1} \times 8.412\\& = & \text{-36 590 J}\cdot \text{mol}^{-1}\\& = & \textbf{-36.6 kJ}\cdot \text{mol}^{-1}\\\end{array}[/tex]
2. Direction of spontaneity
ΔG is negative, so the reaction is spontaneous in the forward direction.
Why do you think sodium bicarbonate is included to neutralize an acidic spill rather than sodium hydroxide?
Imagine a hypothetical situation in which 250 mL of diethyl ether (SDS) has spilled inside of a chemical fume hood onto a stir plate that is plugged in and stirring. Discuss the risks associated with this situation (location, size, compound spilled, and external hazards), and then explain how this spill should be managed.
Answer:
Acid spills should be neutralized with sodium bicarbonate and then cleaned up with a paper towel or sponge.
Explanation:
Which resulted from the study of chemistry?
A) Alchemy to turn base metals into noble metals
B) The understanding of earth, air, fire, and water as the basic components of matter.
C) A supernatural, mystical view of the world.
D) Discovering the role of oxygen in combustion
Help please.☺️☺️☺️☺️☺️
Answer:
A.∆s>0contribute to spontaneity.
How many grams of sodium phosphate are needed to have 1.67 moles of sodium ion?
Answer:
91.29 g of Na₃PO₄ are needed to produce 1.67 moles of sodium ions.
Explanation:
The formula for sodium phosphate is Na₃PO₄
Molar mass of sodium phosphate = 164 g/mol
The dissociation of one mole of sodium phosphate produces 3 moles of sodium ions;
Na₃PO₄ ------> 3Na⁺ + PO₄³
Number of moles of Na₃PO₄ that will produce 1.67 moles of Na⁺ = 1/3 * 1.67 = 0.556 moles of Na₃PO₄
Mass of 0.556 moles of Na₃PO₄ = 0.556 moles * 164 g/mol = 91.29 g
Therefore, 91.29 g of Na₃PO₄ are needed to produce 1.67 moles of sodium ions.
What is the pH of a 0.02M solution of sodium acetate (pka=4.74) to which you add HCl to a final concentration of 0.015M?
Answer:
pH = 5.22
Explanation:
As you can see, your initial concentration of sodium acetate (NaCH₃COO) is 0.02M (0.02mol /L). When you add HCl, the reaction is:
NaCH₃COO + HCl → CH₃COOH + NaCl.
If you add HCl, and final concentration of NaCH₃COO is 0.015M, the concentration of CH₃COOH is 0.005M.
You can know the pH of this solution using H-H equation:
pH = pKa + log {NaCH₃COO} / {CH₃COOH}
pH = 4.74 + log {0.015M} / {0.005M}
pH = 5.22some students believe that teachers are full of hot air. If I inhale 3.5 liters of gas at a temperature of 19 degrees Celsius and it heats to a temperature of 58 degrees celsius in my lungs. what is the new volume of the gas?
Answer:
3.97 L
Explanation:
Data obtained from the question include the following:
Initial volume (V1) = 3.5 L
Initial temperature (T1) = 19 °C
Final temperature (T2) = 58 °C
Final volume (V2) =..?
Next, we shall convert celsius temperature to Kelvin temperature. This can be done as shown below:
Temperature (K) = temperature (°C) + 273
T (K) = T (°C) + 273
Initial temperature (T1) = 19 °C
Initial temperature (T1) = 19 °C + 273 = 292 K
Final temperature (T2) = 58 °C
Final temperature (T2) = 58 °C + 273 = 331 K
Finally, we shall determine the new volume of the gas by using Charles' law equation as shown below:
Initial volume (V1) = 3.5 L
Initial temperature (T1) = 292 K
Final temperature (T2) = 331 K
Final volume (V2) =..?
V1 /T1 = V2 /T2
3.5 /292 = V2 /331
Cross multiply
292 x V2 = 3.5 x 331
Divide both side by 292
V2 = (3.5 x 331) / 292
V2 = 3.97 L
Therefore, the new volume of the gas is 3.97 L.
Carbon-14 has a half-life of 5720 years and this is a fast-order reaction. If a piece of wood has converted 75 % of the carbon-14, then how old is it?
Answer:
11445.8years
Explanation:
Half-life of carbon-14 = 5720 years
First we have to calculate the rate constant, we use the formula :
What is the name of the molecule below?
A) 2-pentene
B) pentane
C) 2-pentyne
D) 2-pentane
The name of the molecule which is given below is 2-pentene.
What are alkene?Alkenes are the organic compounds which are composed of carbon and hydrogen atoms, in which double bond is present.
In the given diagram:
Each corner and joints shows the carbon atoms and number of carbon atoms in it is 5.One double bond is present in the 2nd position.So the compound is 2 pentene.
Hence, 2 pentene is the name of the compound.
To know more about alkene, visit the below link:
https://brainly.com/question/6041165
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Arrange the following kinds of electromagnetic radiation in order of increasing wavelength: infrared, green light, red light, radio waves, X rays, ultraviolet light.
Rank from shortest to longest. To rank items as equivalent, overlap them.
infrared
green light
red light
radio waves
X rays
ultraviolet
Answer:
In the other of increasing wavelength we arrange as
X-rays
ultraviolet
green light
red light
infrared
radio waves
Explanation:
In the electromagnetic spectrum, wavelength decreases with increase in the energy of the electromagnetic wave. Since the e-m wave spectrum is arranged in the order of increasing energy (decreasing wavelength) as: Radio wave; infrared; visible light; ultraviolet; x-rays; gamma rays. Within the visible light, the green light has more energy than the red light. Therefore, the arrangement should be in the reverse direction of their increasing energy.
The decomposition of hydrogen peroxide to form water and oxygen gas releases 196.6 kJ per mole of hydrogen peroxide. This reaction occurs when hydrogen peroxide is placed on a cut to sterilize it. How much heat is released when 5.70 mol H2O2 decompose
Answer:
1120.62 kJ
Explanation:
In order to find how much heat is released for 7.70 mol, we have to compare it with the heat released from one mole.
So from the question, we have;
196.6 kJ = 1 mol
x = 5.70
x = 5.70 * 196.6 / 1
x = 1120.62 kJ
How many grams are in 5.87 x 10^21 molecules of sulfur?
Answer:
0.312g
Explanation:
From Avogadro's hypothesis, 1mole of any substance contains 6.02x10^23 molecules. This means that 1mole of sulphur also contains 6.02x10^23 molecules
1mole of sulphur = 32g
If 1 mole(i.e 32g) of sulphur contains 6.02x10^23 molecules
Then, Xg of sulphur will contain 5.87x10^21 molecules i.e
Xg of sulphur = (32x5.87x10^21)/6.02x10^23 = 0.312g
just saying this is not my work, thank Eduard22sly
he answered it on a different page
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https://brainly.com/question/14966520
The final overall chemical equation is Upper Ca upper O (s) plus upper C upper O subscript 2 (g) right arrow upper C a upper C upper O subscript 3 (s).. When the enthalpy of this overall chemical equation is calculated, the enthalpy of the second intermediate equation is halved and has its sign changed. is halved. has its sign changed. is unchanged.
Answer:
the enthalpy of the second intermediate equation is halved and has its sign changed.
Explanation:
Let us take a look at the first and second intermediate reactions as well as the overall reaction equation for the process under review;
First reaction;
Ca (s) + CO₂ (g) + ½O₂ (g) → CaCO₃ (s) ΔH₁ = -812.8 kJ
Second reaction;
2Ca (s) + O₂ (g) → 2CaO (s) ΔH₂ = -1269 kJ
Hence the overall equation is now;
CaO (s) + CO₂ (g) → CaCO₃ (s) ΔH = ?
According to the Hess law of constant heat summation, the enthalpy of the overall reaction is supposed to be obtained as a sum of the enthalpy of both reactions but this will not give the enthalpy of the overall reaction in this case. The enthalpy of the overall reaction is rather obtained by halving the enthalpy of the second intermediate reaction and reversing its sign before taking the sum as shown below;
Enthalpy of Intermediate reaction 1 + ½(- Enthalpy of Intermediate reaction 2) = Enthalpy of Overall reaction
Answer:
A.
Explanation:
Did it on Edge.
Determine the cell notation for the redox reaction given below.
Sn(s) + 2H+(aq) ⟶ Sn2+(aq) + H2(g)
a. H+(aq) | H2(g) | Pt ∥ Sn(s) | Sn2+(aq)
b. H2(g) | H+(aq) | Pt ∥ Sn2+(aq) | Sn(s)
c. Sn2+(aq) | Sn(s) ∥ H2(g) | H+(aq) | Pt
d. Sn(s) | Sn2+(aq) ∥ H+(aq) | H2(g) | Pt
e. Sn(s) | H2(g) ∥ Sn2+(aq) | H+(aq) | Pt
Answer:
The correct answer is d. Sn(s) | Sn²⁺(aq) ∥ H⁺(aq) | H₂(g) | Pt
Explanation:
The half reactions are:
2H⁺(aq) + 2 e- ⟶ H₂(g) (reduction)
Sn(s) ⟶ Sn²⁺(aq) + 2 e- (oxidation)
In the cell notation, there are two electrodes in which are separated the reduction reaction from the oxidation reaction. In the left electrode occurs the oxidation reaction (anode) while in the right electrode occurs the reduction reaction (cathode). The general form of the cell notation is the following:
anode reaction∥ cathode reaction
where the two bars ( ∥ ) represent the physical barrier between the electrodes. A single bar ( | ) is used to represent a phase separation.
In this redox reaction, the half reaction of the anode is Sn(s) ⟶ Sn²⁺(aq) + 2 e-; whereas the half reaction of the cathode is 2H⁺(aq) + 2 e- ⟶ H₂(g).
The componens are written in order according to the half reaction. Since Sn²⁺ and H⁺ ions are in solution, a platinum electrode is used and represented as Pt. Thus, the cell notation is:
Sn(s) | Sn²⁺(aq) ∥ H⁺(aq) | H₂(g) | Pt
A chemistry student weighs out of formic acid into a volumetric flask and dilutes to the mark with distilled water. He plans to titrate the acid with solution. Calculate the volume of solution the student will need to add to reach the equivalence point. Round your answer to significant digits.
The given question is incomplete, the complete question is:
A chemistry student weighs out 0.0349g of formic acid HCHO2 into a 250.mL volumetric flask and dilutes to the mark with distilled water. He plans to titrate the acid with 0.1500M NaOH solution. Calculate the volume of NaOH solution the student will need to add to reach the equivalence point. Round your answer to 3 significant digits.
Answer:
The correct answer is 5.06 ml.
Explanation:
Based on the given information, the weight of formic acid given is 0.0349 grams. The volume of formic acid of V1 given is 250 ml. The molecular mass of formic acid is 46 grams per mole. Now the molarity of formic acid will be,
[HCOOH] = weight * 1000 / molecular mass * volume (ml)
= 0.0349 * 1000 / 46 * 250
= 0.003035 M or M1
The molarity of NaOH given is 0.1500 M or M2
Let us assume that the volume needed to attain equivalence point is V2 ml. The volume V2 can be determined by using the dilution equation,
M1V1 = M2V2
V2 = M1V1/M2
V2 = 0.003035 * 250 / 0.1500
V2 = 5.06 ml.
Hence, the volume of NaOH needed is 5.06 ml.
Drag each image to the correct location on the model. Each image can be used more than once. Apply the rules and principles of electron configuration to draw the orbital diagram of aluminum. Use the periodic table to help you.
Answer:
The answer to your question is given below.
Explanation:
Aluminium has atomic number of 13. Thus, the electronic configuration of aluminium can be written as:
Al (13) —› 1s² 2s²2p⁶ 3s²3p¹
The orbital diagram is shown on the attached photo.
Answer: screen shot
Explanation:
1. The following thermochemical equation is for the reaction of water(l) to form hydrogen(g) and oxygen(g). 2H2O(l)2H2(g) + O2(g) H = 572 kJ How many grams of H2O(l) would be made to react if 110 kJ of energy were provided? _____ grams
2. The following thermochemical equation is for the reaction of carbon monoxide(g) with hydrogen(g) to form methane(g) and water(g). CO(g) + 3H2(g) CH4(g) + H2O(g) H = -206 kJ When 6.27 grams of carbon monoxide(g) react with excess hydrogen(g),_____ kJ of energy are ____ a.evolved b.absorbed
Answer:
1. 6.92 g of H2O
2i. - 46 KJ of energy.
ii. Option A. Evolved.
Explanation:
1. Determination of the mass of H2O that would be made to react if 110 kJ of energy were provided.
This can be obtained as follow:
The equation for the reaction is given below
2H2O(l) —> 2H2(g) + O2(g) H = 572 kJ
Next, we shall determine the mass of H2O required to produce 572 kJ from the balanced equation.
Molar mass of H2O = (2x1) + 16 = 18 g/mol
Mass of H2O from the balanced equation = 2 x 18 = 36 g
From the balanced equation above, 36 g of H2O reacted to produce 572 kJ of energy.
Finally, we shall determine the mass of water (H2O) needed to produce 110 kJ of energy.
This is illustrated below:
From the balanced equation above, 36 g of H2O reacted to produce 572 kJ of energy.
Therefore, Xg of H2O will react to 110 kJ of energy i.e
Xg of H2O = (36 x 110)/572
Xg of H2O = 6.92 g
Therefore, 6.92 g of H2O is needed to react in order to produce 110 KJ of energy.
2i. Determination of the energy.
The balanced equation for the reaction is given below:
CO(g) + 3H2(g) —> CH4(g) + H2O(g) H = -206 kJ
Next, we shall determine the mass of CO that reacted to produce -206 kJ of energy from the balanced equation.
This is illustrated below:
Molar mass of CO = 12 + 16 = 28 g/mol
Mass of CO from the balanced equation = 1 x 28 = 28 g
From the balanced equation above,
28 g of CO reacted to produce -206 kJ of energy.
Finally, we shall determine the amount of energy produced by reacting 6.27 g of CO. This is illustrated below:
From the balanced equation above,
28 g of CO reacted to produce -206 kJ of energy.
Therefore, 6.27 g of CO will react to produce = (6.27 x -206)/28 = - 46 KJ of energy.
Therefore, - 46 KJ of energy were produced from the reaction.
2ii. Since the energy obtained is negative, it means heat has been given off to the surroundings.
Therefore, the heat is evolved.
Find the molecular formula of each compound CCl , 189.83 g/mol C3H2N , 156.23 g/mol
Answer:
Explanation:
The given formula is empirical formula
Let the molecular formula of first be
[tex]( CCl )_n[/tex]
molecular weight = n x ( 12 + 35.5 )
= 47.5 n
Given molecular weight = 189.83 so
47.5 n = 189.83
n = 3.99 or 4 approx
Molecular formula =
[tex]( CCl )_4[/tex]
= C₄ Cl₄
Let the molecular formula of second compound be
[tex]( C_3H_2N)_n[/tex]
molecular weight = n x ( 3 x 12 +2+14 )
= 52 n
Given molecular weight = 156.23 so
52 n = 156.23
n = 3.0044 or 3 approx
Molecular formula =
[tex]( C_3H_2N )_3[/tex]
= C₉H₆ N₃
Predict the order of acid strengths in the following series of cationic
species: CH3CH2NH3
+, CH3CH=NH2
Answer:
CH3CH=NH2+>CH3CH2NH3+
Explanation:
If we look at the both species under review, we will realize that they are both amines hence they possess the polar N-H bond.
Electrons are ordinarily attracted towards the nitrogen atom hence making both compounds acidic. It is worthy of note that certain features of a compound may make it more acidic than another of close structural proximity. 'More acidic' simply means that the proton is more easily lost.
CH3CH=NH2+ contains an sp2 hybridized carbon atom which is highly electronegative and further withdraws electron density from the N-H bond thereby leading to a greater acidity of CH3CH=NH2+ compared to CH3CH2NH3+
If the heat of combustion for a specific compound is −1380.0 kJ/mol and its molar mass is 44.53 g/mol, how many grams of this compound must you burn to release 822.00 kJ of heat?mass:g
Answer:
Mass = 26.53 g
Explanation:
Heat of combustion = −1380.0 kJ/mol
This means 1 mol of the compound releases 1380 kJ
Molar mass = 44.53 g/mol
This means 1 mol of the compound has a mass of 44.53 g
How many grams would release 822kJ..?
First, we have to obtain the number of moles
1 mol = 1380
x = 822
x = 0.5957 moles
Moles = Mass / Molar mass
Mass = Molar mass * moles
Mass = 44.53 * 0.5957
Mass = 26.53 g
how salt solution can be determined by using hydrometer
Answer:
Salt solution may be calculated by measuring the specific gravity of a sample of water using a hydrometer.
Hope this answer correct (^^)....
Cyclohexane (C6H12) undergoes a molecular rearrangement in the presence of AlCl3 to form methylcyclopentane (CH3C5H9) according to the equation: C6H12 ⇌ CH3C5H9 If Kc = 0.143 at 25°C for this reaction predict the direction in which the system
Answer:
The reaction will shift leftwards, towards the formation of more cyclohexane at 25 °C
Explanation:
Hello,
In this case, for the given chemical reaction, we can write the law of mass action (equilibrium expression) as shown below:
[tex]Kc=\frac{[CH_3C_5H_9]}{[C_6H_{12} ]}[/tex]
Thus, since Kc < 1, we can conclude there are more moles of cyclohexane at equilibrium (denominator is greater than numerator), therefore, the reaction will shift leftwards, towards the formation of more cyclohexane at 25 °C.
Best regards.
Which of the following involves a decrease in entropy? Group of answer choices the dissolution of NaCl in water the evaporation of ethanol the sublimation of carbon dioxide the decomposition of N2O4(g) to NO2(g) the freezing of liquid water into ice
Answer:
the freezing of liquid water into ice
Explanation:
Entropy is the degree of disorderliness of a system, entropy is an extensive property of a thermodynamic system. An extensive property of a system is one whose value changes with the number of particles or the amount of matter present in the system.
Gases possess the greatest entropy among the States of matter followed by liquids and lastly solids. Solid particles do not translate because they are held by strong intermolecular forces.
Hence, a change from liquid to solid implies a decrease in entropy since the solid state possesses less entropy in comparison to the liquid state, hence the answer.
Calculate how much acetylene (C2H2) will be produced from 358 g of H2O and an excess of CaC2 if the percent yield for this reaction is 94.5%. CaC2 2 H2O --> C2H2 Ca(OH)2
Answer:
244.7 g of acetylene
Explanation:
The balanced reaction equation is shown below;
2H20 (l) + CaC2 (s) → Ca(OH)2 (s) + C2H2 (g)
Number of moles of were reacted = reacting mass/molar mass = 358g/18gmol-1 = 19.89 moles of water
From the balanced reaction equation;
2 moles water yields 1 mole of acetylene
19.89 moles of water will yield 19.89 × 1/2 = 9.945 moles of acetylene
Theoretical yield of acetylene = 9.945 moles of acetylene × molar mass of acetylene
Molar mass of acetylene = 26.04 g/mol
Theoretical yield of acetylene = 9.945 moles of acetylene × 26.04 g/mol
Theoretical yield of acetylene = 258.9678 g of acetylene
% yield = actual yield/ theoretical yield × 100
94.5 = actual yield/258.9678 g × 100
Actual yield= 94.5 × 258.9678 g/100
Actual yield = 244.7 g of acetylene
Air contains nitrogen, oxygen, argon, and trace gases. Ifthe partial pressure of nitrogen is 592 mm Hg, oxygen is160 mm Hg, argon is 7 mm Hg, and trace gas is 1 mm Hg,what is the atmospheric pressure
Answer:
760 mmHg
Explanation:
Step 1: Given data
Partial pressure of nitrogen (pN₂): 592 mmHgPartial pressure of oxygen (pO₂): 160 mmHgPartial pressure of argon (pAr): 7 mmHgPartial pressure of the trace gas (pt): 1 mmHgStep 2: Calculate the atmospheric pressure
Since air is a gaseous mixture, the atmospheric pressure is equal to the sum of the gases that compose it.
P = pN₂ + pO₂ + pAr + pt = 592 mmHg + 160 mmHg + 7 mmHg + 1 mmHg = 760 mmHg
consider the following reaction
N2 + 3H2=2NH3
if 30 dm3 of each reactant react together then the volume of mixture at the end is
a 10 dm3
b 20 dm3
c 30 dm3
d 40 dm3
Answer:
d, 40 dm3.
Explanation:
According to Avogadro's law, the mole ratio of chemicals in a reaction is equal to the ratio of volumes of chemicals reacted (for gas).
From the equation, the mole ratio of N2 : H2 : NH3 = 1 : 3 : 2, meaning 1 mole of N2 reacts completely with 3 moles of H2 to give 2 moles of NH3, the ratio of volume required is also equal to 1 : 3 : 2.
Considering both N2 and H2 have 30dm3 of volume, but 1 mole of N2 reacts completely with 3 moles of H2, so we can see H2 is limiting while N2 is in excess. Using the ratio, we can deduce that 10dm3 equals to 1 in ratio (because 3 moles ratio = 30dm3).
With that being said, all H2 has reacted, meaning there's no volume of H2 left. 2 moles of NH3 is produced, meaning the volume of NH3 produced = 10 x 2 = 20 dm3. (using the ratio again)
1 mole of N2 has reacted, meaning from the 30dm3, only 10 dm3 has reacted. This also indicate that 20 dm3 of N2 has not been reacted.
So at the end, the mixture contains 20dm3 of NH3, and 20 dm3 of unreacted N2. Hence, the answer is d, 40 dm3.
Suppose you titrate 25.00 mL of 0.200 M KOBr with 0.200M H2SO4. The pH at half-equivalence point is 7.75 a). What is the initial pH of the 25.00mL of 0.200M KOBr mentioned above
Answer:
Approximately [tex]10.88[/tex].
Explanation:
Equilibrium constant[tex]\rm OBr^{-}[/tex] can act as a weak Bronsted-Lowry base:
[tex]\rm OBr^{-}\; (aq) + H_2O\; (l) \rightleftharpoons HOBr\; (l) + OH^{-}\; (aq)[/tex].
(Side note: the state symbol of [tex]\rm HOBr[/tex] in this equation is [tex]\rm (l)[/tex] (meaning liquid) because [tex]\rm HOBr[/tex] is a weak acid.)
However, the equilibrium constant of this reaction, [tex]K_\text{eq}[/tex], isn't directly given. The idea is to find [tex]K_\text{eq}[/tex] using the [tex]\rm pH[/tex] value at the half-equivalence point. Keep in mind that this system is at equilibrium all the time during the titration. If temperature stays the same, then the same [tex]K_\text{eq}[/tex] value could also be used to find the [tex]\rm pH[/tex] of the solution before the acid was added.
At equilibrium:
[tex]\displaystyle K_\text{eq} = \frac{[\rm HOBr\; (l)]\cdot [\rm OH^{-}\; (aq)]}{[\rm OBr^{-}\; (aq)]}[/tex].
At the half-equivalence point of this titration, exactly half of the base, [tex]\rm OBr^{-}[/tex], has been converted to its conjugate acid, [tex]\rm HOBr[/tex]. Therefore, the half-equivalence concentration of [tex]\rm OBr^{-}[/tex] and [tex]\rm HOBr[/tex] should both be equal to one-half the initial concentration of [tex]\rm OBr^{-}[/tex].
As a result, the half-equivalence concentration of [tex]\rm OBr^{-}[/tex] and [tex]\rm HOBr[/tex] should be the same. The expression for [tex]K_\text{eq}[/tex] can thus be simplified:
[tex]\begin{aligned}& K_\text{eq} \\&= \frac{\left(\text{half-equivalence $[\rm HOBr\; (l)]$}\right)\cdot \left(\text{half-equivalence $[\rm OH^{-}\; (aq)]$}\right)}{\text{half-equivalence $[\rm OBr^{-}\; (l)]$}}\\ &=\text{half-equivalence $[\rm OH^{-}\; (aq)]$}\end{aligned}[/tex].
In other words, the [tex]K_\text{eq}[/tex] of this system is equal to the [tex]\rm OH^{-}[/tex] concentration at the half-equivalence point. Assume that [tex]\rm p\mathnormal{K}_\text{w}[/tex] the self-ionization constant of water, is [tex]14[/tex]. The concentration of [tex]\rm OH^{-}[/tex] can be found from the [tex]\rm pH[/tex] value:
[tex]\begin{aligned}& \text{half-equivalence $[\rm OH^{-}\; (aq)]$} \\ &= 10^{\rm pH - p\mathnormal{K}_\text{w}}\;\rm mol \cdot L^{-1} \\ &= 10^{7.75 - 14}\; \rm mol \cdot L^{-1}\\ &= 10^{-6.25}\; \rm mol \cdot L^{-1}\end{aligned}[/tex].
Therefore, [tex]\begin{aligned} K_\text{eq} &= 10^{-6.25}\end{aligned}[/tex].
Initial pH of the solutionAgain, since [tex]\rm KOBr[/tex] is a soluble salt, all that [tex]0.200\; \rm M[/tex] of [tex]\rm KOBr[/tex] in this solution will be in the form of [tex]\rm K^{+}[/tex] and [tex]\rm OBr^{-}[/tex] ions. Before any hydrolysis takes place, the concentration of [tex]\rm OBr^{-}[/tex] should be equal to that of [tex]\rm KOBr[/tex]. Therefore:
[tex]\text{$[\rm OBr^{-}\; (aq)]$ before hydrolysis} = 0.200\; \rm M[/tex].
Let the equilibrium concentration of [tex][\rm OH^{-}\; (aq)][/tex] be [tex]x\; \rm M[/tex]. Create a RICE table for this reversible reaction:
[tex]\begin{array}{c|ccccccc} & \rm OBr^{-}\; (aq) &+&\rm H_2O\; (l)& \rightleftharpoons & \rm HOBr\; (l)& + & \rm OH^{-}\; (aq) \\ \textbf{I}& 0.200\; \rm M & & & & 0 \; \rm M & & 0\; \rm M \\ \textbf{C} & -x\; \rm M & & & & +x \; \rm M & & +x\; \rm M \\ \textbf{E}& (0.200 + x)\; \rm M & & & & x \; \rm M & & x\; \rm M \end{array}[/tex].
Assume that external factors (such as temperature) stays the same. The [tex]K_\text{eq}[/tex] found at the half-equivalence point should apply here, as well.
[tex]\displaystyle K_\text{eq} = \frac{[\rm HOBr\; (l)]\cdot [\rm OH^{-}\; (aq)]}{[\rm OBr^{-}\; (aq)]}[/tex].
At equilibrium:
[tex]\displaystyle \frac{[\rm HOBr\; (l)]\cdot [\rm OH^{-}\; (aq)]}{[\rm OBr^{-}\; (aq)]} = \frac{x^2}{0.200 + x}[/tex].
Assume that [tex]x[/tex] is much smaller than [tex]0.200[/tex], such that the denominator is approximately the same as [tex]0.200[/tex]:
[tex]\displaystyle \frac{[\rm HOBr\; (l)]\cdot [\rm OH^{-}\; (aq)]}{[\rm OBr^{-}\; (aq)]} = \frac{x^2}{0.200 + x} \approx \frac{x^2}{0.200}[/tex].
That should be equal to the equilibrium constant, [tex]K_\text{eq}[/tex]. In other words:
[tex]\displaystyle \frac{x^2}{0.200} \approx K_\text{eq} = 10^{-6.25}[/tex].
Solve for [tex]x[/tex]:
[tex]x \approx 3.35\times 10^{-4}[/tex].
In other words, the [tex]\rm OH^{-}[/tex] before acid was added was approximately [tex]3.35\times 10^{-4}\; \rm M[/tex], which is the same as [tex]3.35\times 10^{-4}\; \rm mol \cdot L^{-1}[/tex]. Again, assume that [tex]\rm p\mathnormal{K}_\text{w} = 14[/tex]. Calculate the [tex]\rm pH[/tex] of that solution:
[tex]\begin{aligned}\rm pH &= \rm p\mathnormal{K}_\text{w} + \log [\mathrm{OH^{-}}] \approx 10.88\end{aligned}[/tex].
(Rounded to two decimal places.)
Mrs. Wilson leaves her freshly-baked blueberry pie on the windowsill to cool. The delicious fragrance diffuses through the air with a diffusion coefficient of D = 0.2 cm2/s. How long does it take for Dennis to smell the pie in his treehouse 10 meters away? Give your answer in days, without entering the unit.
Answer:
Poop Buttt.
Explanation:
Amanda is doing a report for her Earth Science class about the four seasons. Which of the following would be an effective scientific model to incorporate in her project? a. A calendar indicating the first days of autumn, winter, spring, and summer b. Four earth models, each with a different tilt to represent the earth’s position relative to the sun, lined up in order of season c. A poster board with pictures of weather characteristic of the four seasons d. A bar graph indicating average high and low temperatures for Amanda’s area in the autumn, winter, spring, and summer Please select the best answer from the choices provided
Answer:
(B)
Explanation:
edg 2020
The four seasons in earth is originating from the earth's revolution around the sun. Therefore, the most suitable model for Amanda is Four earth models, each with a different tilt to represent the earth’s position relative to the sun, lined up in order of season.
What are seasons?Seasons in earth is originating from the difference in the distance from the sun over each time period. Hence, revolution of earth around sun make these seasons.
The time period at which earth comes closer to sun more hot will be earth's surface and we experience summer season. When we far from sun winter season occurs.
Therefore, different season are coming based on the distance of earth from sun at each revolution point. This is also affected by the tilt of earth's in its own axis.
Hence, different earth models with different distance from sun is most suitable model here for Amanda. Thus option B is correct.
To find more about seasons, refer the link below:
https://brainly.com/question/4410000
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What is the magnetic quantum number value for an element with n = 1?
Answer:
0,
Explanation:
if n was 2, then 1,0,-1
Daniel has a sample of pure copper.its mass is 89.6 grams (g),and its volume is 10 cubic centimeters (cm3). whats the destiny of the sample.
Answer:
8.96g \ cm3
Explanation:
(89.6\ 10) (g\ cm3) = 8.96g\cm3