Answer:
d. 2500
Explanation:
In a kinetic study with 3 different reactants, you change concentrations of the reactants to see how this concentration affects rate of reaction. General law is:
v = k [A]ᵃ [B]ᵇ [C]ⁿ
If you see 1 and 3 experiments, the concentration of C change from 0.600M to 0.200M but reaction rate doesn't change, thus n=0:
v = k [A]ᵃ [B]ᵇ [C]⁰
v = k [A]ᵃ [B]ᵇ×1
Now, reaction 2 and reaction 4 change B from 0.400M to 0.200M having the other reactants constant. When B is duplicated, rate increase 4 times. That means b = 2:
v = k [A]ᵃ [B]ᵇ
v = k [A]ᵃ [B]²
Finally, if you see 3 and 4 reactions, A change from 0.200M to 0.600M and the reaction rate change from 15.0 to 5.0, That means if the concentration of A is triplicated, reaction rate will be triplicated to. Thus a=1:
v = k [A]ᵃ [B]²
v = k [A] [B]²
Relpacing this equation in any experiment (Experiment 5, for example):
20.0 = k [0.200] [0.200]²
2500 = k
That means right answer is:
d. 2500A pressure cooker contains 5.68 liters of air at a temperature of 394 K. If the absolute pressure of the air in the pressure cooker is 205 pascals, how many moles of air are in the cooker? The cooker contains _______ moles of air. 1 SEE ANSWER
Answer:
Explanation:
We shall find out volume of air at NTP or at 273 K and 10⁵ Pa ( 1 atm )
Let it be V₂
[tex]\frac{P_1V_1}{T_1} =\frac{P_2V_2}{T_2}[/tex]
[tex]\frac{2\times 10^5\times 5.68}{394} =\frac{10^5\times V_2}{273}[/tex]
V₂ = 7.87 litres
22.4 litres of any gas is equivalent to 1 mole
7.87 litres of air will be equivalent to
7.87 / 22.4 moles
= .35 moles .
Calculate the net change in enthalpy for the formation of one mole of acrylic acid from calcium carbide, water and carbon dioxide from these reactions. Round your answer to the nearest .
Answer:
-471 Kj/mole acrylic acid
Explanation:
THIS IS THE COMPLETE QUESTION BELOW;
There are two steps in the usual industrial preparation of acrylic acid, the immediate precursor of several useful plastics. In the first step, calcium carbide and water react to form acetylene and calcium hydroxide: CaC (s) + 2 H2O(g) - CH (9) + Ca(OH),(s) AH -414. kJ In the second step, acetylene, carbon dioxide and water react to form acrylic acid: 6 C H (9) + 3 CO2(9) + 4H2O(g) - SCH,CHCO,H) AH-132. kJ Calculate the net change in enthalpy for the formation of one mole of acrylic acid from calcium carbide, water and carbon dioxide from these reactions. Round your answer to the nearest kJ. x 5 ?
The two equations from the reaction can be written as;
a)CaC₂(s) + 2H₂O(l) ------->C₂H₂(g) + CaOH₂(s)
Δ H= -414Kj ........................ equation (a)
b)6C₂H₂(g) +3CO₂(g)+4H₂O(g) -------> 5CH₂CHCO₂H(g) Δ H= 132Kj ...................... equation (b)
In equation (b)acrylic acid was produced by the reaction between Acetylene carbon dioxide and water
Then we can multiply equation(a) by factor of 6 and the ΔH Then we have (6× -414Kj)= ΔH= -2484Kj.
6CaC₂(s) + 12H₂O(l) ------->6C₂H₂(g) + 6CaOH₂(s)
Δ H= -2484Kj.................. equation (c)
6C₂H₂(g) +3CO₂(g)+4H₂O(g) -------> 5CH₂CHCO₂H(g) Δ H= 132Kj
Then add equation (c) and equation(b) then we have
6CaC₂(s) + 16H₂O(l)+3CO₂(g)------> 5CH₂CHCO₂H(g) + 6CaOH₂(s) ΔH= -2352Kj
ΔH(net)= -2352Kj/5moles
=-471Kj/mole
therefore, net change in enthalpy for the formation of one mole of acrylic acid from calcium carbide, water and carbon dioxide from these reactions. Round your answer to the nearest kJ. x 5 ? is -471Kj/mole acrylic acid
the equilibrium concentrations were found to be [H2O]=0.250 M , [H2]=0.600 M , and [O2]=0.800 M . What is the equilibrium constant for this reaction?
Answer:
Keq = 0.217
Explanation:
Let's determine the equilibrium reaction.
In gaseous state, water vapor can be decomposed to hydrogen and oxygen and this is a reversible reaction.
2H₂(g) + O₂(g) ⇄ 2H₂O (g) Keq
Let's make the expression for the equilibrium constant
Products / Reactants
We elevate the concentrations, to the stoichiometry coefficients.
Keq = [H₂O]² / [O₂] . [H₂]²
Keq = 0.250² / 0.8 . 0.6² = 0.217
The Haber Process is the main industrial procedure to produce ammonia. The reaction combines nitrogen from air with hydrogen mainly from natural gas (methane) and is reversible and exothermic. The enthalpy change for this reaction is - 92 kJ mol-1. In an experiment, 1.5 moles of N2 and 4.0 moles of H2 is mixed in a 1.50 dm3 reaction vessel at 450 °C. After reaching equilibrium, the mixture contained 0.9 mole of NH3.
A) With the above information, write the reaction equilibrium equation in the Haber process. t.
B) Calculate Kc for this reaction.
C) What is the equilibrium yield of ammonia in this reaction?
D) Referring to Le Chatelier's principle and above information, suggest two ways to increase the yield of ammonia in this reaction and explain.
Answer:
A) [tex]N_2(g)+3H_2(g)\rightleftharpoons 2NH_3(g)[/tex].
B) [tex]Kc=0.0933[/tex].
C) 0.9 mol.
D) Increasing both temperature and pressure.
Explanation:
Hello,
In this case, given the information, we proceed as follows:
A)
[tex]N_2(g)+3H_2(g)\rightleftharpoons 2NH_3(g)[/tex]
B) For the calculation of Kc, we rate the equilibrium expression:
[tex]Kc=\frac{[NH_3]^2}{[N_2][H_2]^3}[/tex]
Next, since at equilibrium the concentration of ammonia is 0.6 M (0.9 mol in 1.5 dm³ or L), in terms of the reaction extent [tex]x[/tex], we have:
[tex][NH_3]=0.6M=2*x[/tex]
[tex]x=\frac{0.6M}{2}=0.3M[/tex]
Next, the concentrations of nitrogen and hydrogen at equilibrium are:
[tex][N_2]=\frac{1.5mol}{1.5L}-x=1M-0.3M=0.7M[/tex]
[tex][H_2]=\frac{4mol}{1.5L}-3*x=2.67M-0.9M=1.77M[/tex]
Therefore, the equilibrium constant is:
[tex]Kc=\frac{(0.6M)^2}{(0.7M)*(1.77M)^3}\\ \\Kc=0.0933[/tex]
C) In this case, the equilibrium yield of ammonia is clearly 0.9 mol since is the yielded amount once equilibrium is established.
D) Here, since the reaction is endothermic (positive enthalpy change), one way to increase the yield of ammonia is increasing the temperature since heat is reactant for endothermic reactions. Moreover, since this reaction has less moles at the products, another way to increase the yield is increasing the pressure since when pressure is increased the side with fewer moles is favored.
Best regards.
Which of the following best describes the interaction of the alkali metals with water? Select the correct answer below: A. They all dissolve easily in water. B. They do not react or dissolve in water. C. They react strongly with water to produce an alkaline solution and hydrogen. D. They react strongly with water to produce an alkaline solution and oxygen.
Answer:
C. They react strongly with water to produce an alkaline solution and hydrogen
Explanation:
All alkali metals react vigorously with cold water. In the reaction, hydrogen gas is given off and the metal hydroxide is produced.
Hope that helps.
g A spontaneous process is one in which: A. releases a large amount of heat B. may happen (is possible) C. will rapidly approach equilibrium D. will happen quickly
Answer:
A. releases a large amount of heat
Explanation:
A reaction is said to be spontaneous if it can proceed on its own without the addition of external energy. A spontaneous reaction is not determined by the length of time, because some spontaneous reactions are completed after a long period of time. They are exothermic in nature. An example is the conversion of graphite to carbon which takes a long period of time to complete. Spontaneous reactions are known to increase entropy in a system. Entropy is the rate of disorder in a system.
In the combustion of fire, energy is released to the surroundings as there is a decrease in energy. This is an example of a spontaneous reaction because it is an exothermic reaction, which causes an increase in entropy and a decrease in energy.
33. Hydrocarbons that release pleasant odors are called_________
hydrocarbons. (1 point)
Answer:
Aromatic Hydrocarbons
Explanation:
Aromatic (Pleasant Odour) Hydrocarbons are those having pleasant odours.
Answer:
substituted hydrocarbons
Explanation:
i think
After heating a sample of hydrated CuSO4, the mass of released H2O was found to be 2.0 g. How many moles of H2O were released if the molar mass of H2O is 18.016 g/mol
Answer:
0.1110 mol
Explanation:
Mass = 2g
Molar mass = 18.016 g/mol
moles = ?
These quantities are realted by the following equation;
Moles = Mass / Molar mass
Substituting the values of the quantities and solving for moles, we have;
Moles = 2 / 18.016 = 0.1110 mol
Consider a triangle ABC like the one below. Suppose that C=83°, a = 43, and b = 44. Solve the triangle.
Carry your intermediate computations to at least four decimal places, and round your answers to the nearest tenth.
If there is more than one solution, use the button labeled "or".
Answer:
Explanation:
In a triangle
a / sin A = b / sinB = c / sinC
Putting the values
43 / sin A = 44 / sinB
sinA / sinB = 43 / 44 = 1 / 1.023
A + B = 180 - 83 = 97
sinA / sin ( 97 - A ) = 1 / 1.023
sin 97 cos A - cos 97 sin A = 1.023 sin A
= .9925 cos A + .122 sin A = 1.023 sin A
.9925 cos A = .901 sin A
squaring
.985 cos²A = .8118 sin²A
.985 - .985 sin²A = .8118 sin²A
.985 = 1.7968 sin²A
sinA = .74
A = 47.73
B = 49.27
c / sin C = b / sin B
c = b sinC / sinB
= 44 x sin 83 / sin 49.27
= 44 x .9925 / .7578
= 57.62
Why is phosphorus unusual compared to other group 15 elements? Select the correct answer below: A. There are compounds that contain phosphorus-phosphorus bonds with uncommon oxidation states. B. Phosphorus is relatively unreactive. C. Phosphorus only forms compounds where the oxidation number of phosphorus is 5+. D. Phosphorus is the most electronegative of the group 15 elements.
Answer:
There are compounds that contain phosphorus-phosphorus bonds with uncommon oxidation states.
Explanation:
Phosphorus is a member of group 15 in the periodic table. Its common oxidation States are -3 and +5. Phosphorus is believed to firm some of its compounds by the participation of hybridized d-orbitals in bonding although this is also disputed by some scientists owing to the high energy of d - orbitals.
Phosphorus form compounds having phosphorus-phosphorus bonds in unusual oxidation states such as diphosphorus tetrahydride, H2P-PH2, and tetraphosphorus trisulfide, P4S hence the answer.
what is the IUPAC name of KNO3, Fe(OH)3, H2SO3 and Al2(SO4)3
Answer:
KNO₃ - Potassium nitrate
Fe(OH)₃ - Iron(III) hydroxide
H₂SO3 - Sulfurous acid
Al₂(SO₄)₃ - Aluminum sulfate
Hope that helps.
For each row in the table below, decide whether the pair of elements will form a molecular compound held together by covalent chemical bonds
Answer:
1- yes
HBr--hydrogen bromide
2- no
BaBr₂----barium bromide
3- yes
NCl----- nitrogen chlorine
Hydrogen ,bromine and nitrogen , chlorine are the pair of elements which will form a molecular compound by covalent bond as they have 1, 7,5, 7 valence electrons respectively.
What is a covalent bond?Covalent bond is defined as a type of bond which is formed by the mutual sharing of electrons to form electron pairs between the two atoms.These electron pairs are called as bonding pairs or shared pair of electrons.
Due to the sharing of valence electrons , the atoms are able to achieve a stable electronic configuration . Covalent bonding involves many types of interactions like σ bonding,π bonding ,metal-to-metal bonding ,etc.
Sigma bonds are the strongest covalent bonds while the pi bonds are weaker covalent bonds .Covalent bonds are affected by electronegativities of the atoms present in the molecules.Compounds having covalent bonds have lower melting points as compared to those with ionic bonds.
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Determine which complex of the electron transport chain (respiratory chain) each phrase describes. (Coenzyme Q is also called ubiquinone or ubiquinol, depending on whether it is in oxidized or reduced form.)
Complex I:
Complex II:
Complex III:
Complex IV:
Here are the choices that need to be put in the correct complex:
1) NADH-ubiquinone(NADH-coenzyme Q oxidoreductase)
2) Coenzyme Q-cytochrome c oxidoreductase
3) Electron transfer from succinate to ubiquinone (coenzyme Q)
4) Electron transfer from cytochrome c to O2
5) Succinate-coenzyme Q Oxidoreductase (succinate dehydrogenase)
6) Cytochrome c oxidase
7) Electron transfer from ubiquinol (QH2) to cytochrom c
8) Electron transfer from NADH to ubiquinone (coenzyme Q)
Answer:
Complex I: (1) NADH-ubiquinone(NADH-coenzyme Q oxidoreductase), (8) Electron transfer from NADH to ubiquinone (coenzyme Q)
Complex II: (3) Electron transfer from succinate to ubiquinone (coenzyme Q) (5) Succinate-coenzyme Q Oxidoreductase (succinate dehydrogenase)
Complex III: (2) Coenzyme Q-cytochrome c oxidoreductase, (7) Electron transfer from ubiquinol (QH2) to cytochrome c
Complex IV: (4) Electron transfer from cytochrome c to O2, (6) Cytochrome c oxidase
Explanation:
The electron transport chain (ETC) in the mitochondria provides a pathway by which electrons are transferred from NADH and FADH₂ through a series of membrane-bound carriers to molecular oxygen reducing it to water.
The electron transport chain electron carriers are organized into four complexes, Complexes I - IV.
Complex I : It is also called NADH:ubiquinone reductase. It transfers electrons from NADH to ubiquinone (also known as coenzyme Q)
Complex II : It is also called succinate dehydrogenase. It functions to tranfer electrons from succinate to FAD and then to ubiquinone.
Complex III : It is also called ubiquinone:cytochrome c oxidoreductase. It functions to transfer electrons from ubiquinol (reduced ubiquinone) to cytochrome c.
Complex IV : It is also called cytochrome oxidase. It functions to transfer electrons from cytochrome c to molecular oxygen reducing it to water.
The electron transporter chain is a series of enzymatic reactions to produce and store energy for the organism’s correct functioning. Complex I: 1 and 8. Complex II: 3 and 5. Complex III: 2 and 7. Complex IV: 4 and 6.
---------------------------------
Electron transporter chain
The electron transporter chain is located in the internal mitochondrial membrane. It constitutes a series of enzymatic reactions to release and save energy for the organism’s correct functioning.
Along the chain, there are four proteinic complexes in the membrane, I, II, III, and IV, that contain the electrons transporters and the enzymes necessary to catalyze the electrons' transference from one complex to the other.
Different redox reactions occur to pass electrons along the chain.
Released energy creates a proton concentration gradient used to synthesize ATP.
1) NADH provides electrons to the first complex, Complex I (NADH-
ubiquinone or NADH-coenzyme Q oxidoreductase).
From there, electrons go to the coenzyme Q (Ubiquinone) that carries them to complex II and III. Meanwhile, complex I pomp four protons to the intermembrane space.
2) Complex II (succinate-dehydrogenase) receives electrons from CoQ and also receives electrons from FADH2. Electrons are sent from complex II to ubiquinone Q that carries these electrons to complex III.
3) Complex III (Cytochrome C-reductase) receives electrons from ubiquinone Q and pomps protons to the intermembrane space.
Electrons are transferred to Cytochrome c.
Electrons travel from cytochrome c to complex IV.
4) Complex IV (Cytochrome C-oxidase) is the last complex that pomps protons to the intermembrane space. It takes electrons from cytochrome C and sends them to oxygen.
5) Electrons are sent to O₂ molecules, which also receive protons in the matrix to create water molecules.
Four electrons are needed to produce two water molecules from one O₂ molecule.
The proton gradient is used to produce ATP molecules.
Now, we can join the complexes with the phrases.
Complex I:
1) NADH-ubiquinone (NADH-coenzyme Q oxidoreductase)
8) Electron transfer from NADH to ubiquinone (coenzyme Q)
Complex II:
3) Electron transfer from succinate to ubiquinone (coenzyme Q)
5) Succinate-coenzyme Q Oxidoreductase (succinate dehydrogenase)
Complex III:
2) Coenzyme Q - cytochrome c oxidoreductase
7) Electron transfer from ubiquinol (QH₂) to cytochrom c
Complex IV:
6) Cytochrome C oxidase
4) Electron transfer from cytochrome c to O₂
-----------------------------------
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The decomposition of hydrogen peroxide is catalyzed by iodide ion. The catalyzed reaction is thought to proceed by a two-step mechanism:
Answer:
The two-step mechanism is a slow mechanism and a fast mechanism. When we combine them, the result is
2H₂O₂ (aq) ⇒2H₂O (l) + O₂ (g)
Explanation:
We know that the decomposition of hydrogen peroxide is catalyzed by iodide ion, which means that the iodide ion will react with the hydrogen peroxide. There is a slow mechanism and a fast one:
H₂O₂(aq) + I₋(aq) ⇒ H₂O(l) + IO₋(aq) this is the slow reaction
IO₋(aq) + H₂O₂(aq)⇒ H₂O(l) + O₂(g) + I₋ (aq) this is the fast reaction
If we cancel the same type of molecules and ions, the final result is:
2H₂O₂ (aq) ⇒2H₂O (l) + O₂ (g)
The two-step mechanism represents the slow mechanism and a fast mechanism. At the time of combining them, the result is 2H₂O₂ (aq) ⇒2H₂O (l) + O₂ (g)
Two-step mechanism:
The decomposition of hydrogen peroxide should be catalyzed by iodide ion, which represents the iodide ion will react with the hydrogen peroxide. There is a slow mechanism and a fast one
Now
H₂O₂(aq) + I₋(aq) ⇒ H₂O(l) + IO₋(aq) this is the slow reaction
IO₋(aq) + H₂O₂(aq)⇒ H₂O(l) + O₂(g) + I₋ (aq) this is the fast reaction
Now in case of cancelling, the same type of molecules and ions, the final result is 2H₂O₂ (aq) ⇒2H₂O (l) + O₂ (g)
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Calculate the heat absorbed by a sample of water that has a mass of 45.00 g when the temperature increases from 21.0oC to 38.5 oC. (s=4.184 J/g.o C)
Answer:
The heat absorbed by the sample of water is 3,294.9 J
Explanation:
Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.
The sensible heat of a body is the amount of heat received or transferred by a body when it undergoes a temperature variation (Δt) without there being a change of physical state (solid, liquid or gaseous). Its mathematical expression is:
Q = c * m * ΔT
Where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation.
In this case:
Q=?m= 45 gc= 4.184 [tex]\frac{J}{g*C}[/tex]ΔT= Tfinal - Tinitial= 38.5 C - 21 C= 17.5 CReplacing:
Q= 4.184 [tex]\frac{J}{g*C}[/tex] * 45 g* 17.5 C
Solving:
Q=3,294.9 J
The heat absorbed by the sample of water is 3,294.9 J
The equilibrium between carbon dioxide gas and carbonic acid is very important in biology and environmental science. CO2 ( aq) + H2O ( l) H2CO3 ( aq) Which one of the following is the correct equilibrium constant expression (K c) for this reaction?
a) K =[H2CO3]/ [CO2]
b) K=[CO2]/ [H2CO3]
c) K=[H2CO3]/ [CO2][H2O]
d) K=[CO2][H2O]/ [H2CO3]
e) K=1/[H2CO3]
Answer:
Kc = [H₂CO₃] / [CO₂]
Explanation:
Equilibrium constant expression (Kc) of any reaction is defined as the ratio between molar concentrations in equilibrium of products over reactants.
Pure solids and liquids don't affect the equilibrium and you don't have to take its concentrations in the equilibrium.
Also, each specie must be powered to its reactant coefficient.
For example, for the reaction:
aA(s) + bB(aq) ⇄ cC(l) + nD(g) + xE(aq)
The equilibrium constant, kc is:
Kc = [D]ⁿ / [B]ᵇ[E]ˣ
You don't take A nor C species because are pure solids and liquids. b, n and x are the reactant coefficients of each substance. Ratio of products over reactants
Thus, for the reaction:
CO₂(aq) + H₂O(l) ⇄ H₂CO₃(aq)
The Kc is:
Kc = [H₂CO₃] / [CO₂]
Match the symbol with the appropriate definition.
a. ΔG
b. ΔS
c. Keq
d. ΔH
e. ΔG°
f. J
1. Equation constant
2. Change in size
3. Change in entropy
4. Change in gas pressure
5. Change in stored energy
6. Equilibrium constant
7. Change in enthalpy
8. Joule
9. Standard free energy charge
10. Change in energy
Answer:
a. ΔG : It seems that the proper definition is not given, anyway, it is the free energy change.
b. ΔS : 3. Change in entropy.
c. Keq : 6. Equilibrium constant.
d. ΔH : 7. Change in enthalpy.
e. ΔG° : 9. Standard free energy change.
f. J : 8. Joule.
Explanation:
Hello,
In this case, we can match the symbol with the proper definition as shown below:
a. ΔG : It seems that the proper definition is not given, anyway, it is the free energy change and it uses G since it is better referred to the Gibbs free energy.
b. ΔS : 3. Change in entropy.
c. Keq : 6. Equilibrium constant.
d. ΔH : 7. Change in enthalpy.
e. ΔG° : 9. Standard free energy change.
f. J : 8. Joule.
Best regards.
PLEASE HELP ME Calculate the change in boiling point when 0.402 moles of sodium chloride are added to 0.200 kilograms of water. Kf = -1.86°C/m; Kb = 0.512°C/m -2.1°C 2.1°C -7.5°C 7.5°C
Answer:
The change in the boiling point would be 2.1°C.
Explanation:
1 ) Let us first determine the molarity of this solution :
M = mol / kg,
M = 0.402 mol / 0.200 kg = 2.01 M NaCl
2 ) ΔT = i [tex]*[/tex] K [tex]*[/tex] m
ΔT = 2 [tex]*[/tex] 0.512C/m [tex]*[/tex] 2.01m
ΔT = 2.06C
As you can see, this is none of the answer choices. However the van't Hoff factor i in this case was taken to be 2, but this value is actually less than the predicted ideal solution. This is due to the ion pairing, causing i to be around 1.7 to 1.8. Therefore our solution is option b, 2.1°C.
Rank the solutions in order of decreasing [H3O+]. Rank solutions from largest to smallest hydronium ion concentration.
a. 0.10 M HNO3HNO3
b. 0.10 M HClO2HClO2
c. 0.10 M HCNHCN
d. 0.10 M HC2H3O2
Treatment of 1 mole of dimethyl sulfate with 2 moles of sodium acetylide results in the formation of propyne as the major product.
A) Draw a reasonable mechanism accounting for the formation of the byproduct 2-butyne.
B) 2-Butyne is observed as a minor product of this reaction. Draw a mechanism accounting for the formation of this minor product and explain how your proposed mechanism is consistent with the observation that acetylene is present among the reaction products.
C) Predict the major and minor products that are expected if diethyl sulfate is used in place of dimethyl sulfate.
Answer:
(a) appended underneath is the inorganic ion shaped in the reaction and the mechanism of its formation
(b) 2-butyne framed as a minor product is appeared in the connection. It is shaped when the monosodium subordinate of dimethylsulphoxide gets a hydrogen from the propyne and reacts again with monosodium methylsulphoxide.
(c) The major product framed when diethylsulphoxide is utilized, would be butyne and minor product would be 3-hexyne.
Explanation:
attached below is diagram
What are representative elements"?
A. Elements in the short columns of the periodic table
B. Elements in the same row of the periodic table
C. Elements that share the same properties on the periodic table
D. Elements in the tall columns of the periodic table
The representative elements are the elements in the tall columns of the periodic table.
What are the representative elements?The representative elements that can also be referred to as the main group elements. They can be used to represent the chemistry of the group to which they belong.
Hence, the representative elements are the elements in the tall columns of the periodic table.
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30. What is the Bronsted base of H2PO4- + OH- ⟶HPO42- + H2O?
Answer:
OH⁻ is the Bronsted-Lowry base.
Explanation:
A Bronsted-Lowry base is a substance that accepts protons. In the chemical equation, OH⁻ accepts a proton from H₂PO₄⁻ to become H₂O. H₂PO₄⁻ would be a Bronsted-Lowry acid because it donates a proton to OH⁻ and becomes HPO₄²⁻.
Hope that helps.
The titration of 78.5 mL of an unknown concentration H3PO4 solution requires 134 mL of 0.224 M KOH solution. What is the concentration of the H3PO4 solution
Answer:
0.127 M.
Explanation:
The balanced equation for the reaction is given below:
H3PO4 + 3KOH —› K3PO4 + 3H2O
From the balanced equation above, we obtained the following data:
Mole ratio of acid, H3PO4 (nA) = 1
Mole ratio of base, KOH (nB) = 3
Data obtained from the question include:
Volume of acid, H3PO4 (Va) = 78.5 mL
Molarity of acid, H3PO4 (Ma) =...?
Volume of base, KOH (Vb) = 134 mL
Molarity of base, KOH (Mb) = 0.224 M
The concentration of the acid, H3PO4 can be obtained as follow:
MaVa / MbVb = nA/nB
Ma x 78.5 / 0.224 x 134 = 1/3
Cross multiply
Ma x 78.5 x 3 = 0.224 x 134 x 1
Divide both side by 78.5 x 3
Ma = (0.224 x 134 x 1) /(78.5 x 3)
Ma = 0.127 M
Therefore, the concentration of the acid, H3PO4 is 0.127 M.
Suppose of copper(II) acetate is dissolved in of a aqueous solution of sodium chromate. Calculate the final molarity of copper(II) cation in the solution. You can assume the volume of the solution doesn't change when the copper(II) acetate is dissolved in it. Round your answer to significant digit.
Answer:
Molarity Cu²⁺ = 0.423M Cu²⁺
Explanation:
40.8g of copper (II) acetate into 200mL of a 0.700M sodium chromate
The reaction of copper acetate with sodium chromate occurs as follows:
Cu(CH₃COO)₂(aq) + Na₂CrO₄(aq) → CuCrO₄(s) + 2CH₃COONa
In water, the Copper(II) acetate dissociates in Cu²⁺ cation.
To know final molarity of Cu²⁺ we need to calculate the moles of Cu²⁺ that don't react with chromate ion, thus:
Moles of 40.8g of copper(II) acetate (Molar mass: 181.63g/mol) are:
40.8g × (1mol / 181.63g) = 0.2246 moles of Copper(II) acetate
Moles of sodium chromate are:
0.200L ₓ (0.700mol / L) = 0.140 moles of sodium chromate.
As 1 mole of Copper(II) acetate reacts per mole of sodium chromate, moles of Copper(II) acetate = Moles of Cu²⁺ that remains after the reaction are:
0.2246mol - 0.140moles = 0.0846 moles of Cu²⁺
Molarity is ratio between moles of solute (Moles Cu²⁺) and volume in liters of solution (200mL = 0.200L):
Molarity Cu²⁺ = 0.0846 moles / 0.200L
Molarity Cu²⁺ = 0.423M Cu²⁺What is the magnetic quantum number value for an element with n = 1?
Answer:
ml= 0
Explanation:
The magnetic quantum number usually gives information regarding the directionality of an atomic orbital. The values of the magnetic quantum number ranges between integer values that lie between +l to -l.
However, the n=1 level contains only the 1s orbital which is spherically symmetrical. The s orbital having l=0 also has magnetic quantum number (ml) =0, hence the answer.
A compound decomposes with a half-life of 8.0 s and the half-life is independent of the concentration. How long does it take for the concentration to decrease to one-ninth of its initial value
Answer:
The concentration takes 25.360 seconds to decrease to one-ninth of its initial value.
Explanation:
The decomposition of the compound has an exponential behavior and process can be represented by this linear first-order differential equation:
[tex]\frac{dc}{dt} = -\frac{1}{\tau}\cdot c(t)[/tex]
Where:
[tex]\tau[/tex] - Time constant, measured in seconds.
[tex]c(t)[/tex] - Concentration of the compound as a function of time.
The solution of the differential equation is:
[tex]c(t) = c_{o} \cdot e^{-\frac{t}{\tau} }[/tex]
Where [tex]c_{o}[/tex] is the initial concentration of the compound.
The time is now cleared in the result obtained previously:
[tex]\ln \frac{c(t)}{c_{o}} = -\frac{t}{\tau}[/tex]
[tex]t = -\tau \cdot \ln \frac{c(t)}{c_{o}}[/tex]
Time constant as a function of half-life is:
[tex]\tau = \frac{t_{1/2}}{\ln 2}[/tex]
Where [tex]t_{1/2}[/tex] is the half-life of the composite decomposition, measured in seconds.
If [tex]t_{1/2} = 8\,s[/tex], then:
[tex]\tau = \frac{8\,s}{\ln 2}[/tex]
[tex]\tau \approx 11.542\,s[/tex]
And lastly, given that [tex]\frac{c(t)}{c_{o}} = \frac{1}{9}[/tex] and [tex]\tau \approx 11.542\,s[/tex], the time taken for the concentration to decrease to one-ninth of its initial value is:
[tex]t = -(11.542\,s)\cdot \ln\frac{1}{9}[/tex]
[tex]t \approx 25.360\,s[/tex]
The concentration takes 25.360 seconds to decrease to one-ninth of its initial value.
Calculate the frequency (Hz) and wavelength (nm)
of the emitted photon when an electron drops from
the n = 4 to the n=2 level in a hydrogen atom
Answer:
wavelength, λ = 486.6 nm
frequency, f = 6.16 * 10¹⁴ Hz
Explanation:
a. Wavelength
Using the wavelength equation; 1/λ = (1/hc) * 2.18 * 10⁻¹⁸ J * (1/nf² - 1/ni²)
Where nf is the final energy level; ni is the initial energy level; h is Planck's constant = 6.63 * 10⁻³⁴ J.s; c is velocity of light = 3 * 10⁸ m/s
1/λ = 1/(6.63 * 10⁻³⁴ J.s * 3 * 10⁸ m/s) * 2.18 * 10⁻¹⁸ J * (1/2² - 1/4²)
1/λ = 2.055 * 10⁶ m
λ = 4.866 * 10⁻⁷ m
wavelength, λ = 486.6 nm
b. Frequency
Using f = c/λ
f = (3 * 10⁸ m/s) / 4.866 * 10⁻⁷ m
frequency, f = 6.16 * 10¹⁴ Hz
The equilibrium constant is given for two of the reactions below. Determine the value of the missing equilibrium constant. A(g) + 2B(g) ↔ AB2(g) Kc = 59 AB2(g) + B(g) ↔ AB3(g) Kc = ? A(g) + 3B(g) ↔ AB3(g) Kc = 478
Answer:
The correct answer is 8.10
Explanation:
Given:
A(g) + 2B(g) ↔ AB₂(g) Kc = 59 ---- Eq. 1
A(g) + 3B(g) ↔ AB₃(g) Kc = 478 ----- Eq. 2
We have to rearrange the chemical equations in order to obtain:
AB₂(g) + B(g) ↔ AB₃(g) Kc = ?
AB₂(g) is a reactant, so we have to use the reverse reaction of Eq. 1, in this case Kc= 1/59. Since AB₃(g) is a product, we use the forward reaction of Eq.2, and the constant is the same: Kc= 478. The following is the sum of rearranged chemical equations, and the compounds in bold and italic are canceled:
AB₂(g) ↔ A(g) + 2B(g) Kc₁= 1/59
A(g) + 3B(g) ↔ AB₃(g) Kc₂= 478
-----------------------------------------
AB₂(g) + B(g) ↔ AB₃(g)
If we add reactions at equilibrium, the equilibrium constants Kc are mutiplied as follows:
Kc = Kc₁ x Kc₂ = 1/59 x 478 = 478/59 = 8.10
The value of the missing equilibrium constant is 8.10.
The value of the missing equilibrium constant is 8.10
Chemical Equations:Since
A(g) + 2B(g) ↔ AB₂(g) Kc = 59 ---- Eq. 1
A(g) + 3B(g) ↔ AB₃(g) Kc = 478 ----- Eq. 2
Now we have to rearrange the chemical equations in order to obtain:
AB₂(g) + B(g) ↔ AB₃(g) Kc = ?
Here AB₂(g) represents a reactant, so we have to applied the reverse reaction of Eq. 1, in this case Kc= 1/59. Since AB₃(g) is a product, we use the forward reaction of Eq.2, and the constant should be the same: Kc= 478.
The following is the sum of rearranged chemical equations, and the compounds in bold and italic should be canceled:
AB₂(g) ↔ A(g) + 2B(g) Kc₁= 1/59
A(g) + 3B(g) ↔ AB₃(g) Kc₂= 478
-----------------------------------------
AB₂(g) + B(g) ↔ AB₃(g)
In the case when we add reactions at equilibrium, the equilibrium constants Kc are multiplied as follows:
Kc = Kc₁ x Kc₂ = 1/59 x 478 = 478/59 = 8.10
Learn more about reaction here: https://brainly.com/question/1200811
Concentrated hydrochloric acid, HCl, comes with an approximate molar concentration of 12.1 M. If you are instructed to prepare 350.0 mL of a 0.975 M HCl solution, how many milliliters of the stock (concentrated) HCl solution will you use
Answer:
28.20 mL of the stock solution.
Explanation:
Data obtained from the question include the following:
Molarity of stock solution (M1) = 12.1 M
Volume of diluted solution (V2) = 350.0 mL
Molarity of diluted solution (M2) = 0.975 M
Volume of stock solution needed (V1) =..?
The volume of stock solution needed can be obtained by using the dilution formula as shown below:
M1V1 = M2V2
12.1 x V1 = 0.975 x 350
Divide both side by 12.1
V1 = (0.975 x 350)/12.1
V1 = 28.20 mL.
Therefore, 28.20 mL of the stock solution will be needed to prepare 350.0 mL of 0.975 M HCl solution.
Do you expect the compound Na4S to be a stable sulfur compound? Explain why or why not. Select the correct answer below: A. Yes, because sulfur is significantly more electronegative than sodium, so it can ionize sodium. B. Yes, because sodium is significantly more electronegative than sulfur, so it can ionize sulfur. C. No, because sulfur does not typically form negative ions or oxidation states less than 2−. The binary compound formed by sulfur and sodium is Na2S. D. No, because elemental sulfur is not a strong enough oxidation agent to oxidize sodium.
Answer:
No, because sulfur does not typically form negative ions or oxidation states less than 2−. The binary compound formed by sulfur and sodium is Na2S
Explanation:
Sulphur is a member of group 16. The oxidation states expected for sulphur in group 16 are -1, -2, +1, +2,+3,+4,+5 or +6. The elements of group 16 usually form negative ions with oxidation number of -2. They do not typically form negative ions with oxidation state less than -2.
The implication of this is that we actually do not expect the existence of a compound in which sulphur forms an S^4- anion. In reality, such an anion does not exist. Rather a binary compound of sulphur and sodium will have the formula Na2S because it contains the S^2- anion.