Answer:
In diethyl ether, (CH₃)₂Mg(CH₃)₂Mg, show peaks at -1.46 and -1.74 ppm, at -100 °CIn tetrahydrofuran (THF), monomer (CH₃)₂Mg show peaks at -1.76 and -1.81 ppm, at -60 °CExplanation:
The 1H NMR signal of (CH₃)₂Mg can be obtained in diethyl ether and tetrahydrofuran. (CH₃)₂Mg tends to polymerize in diethyl ether but mostly remain monomer in tetrahydrofuran. The negative value of chemical shifts shows that the protons of (CH₃)₂Mg are more shielded than the protons of TMS.
In diethyl ether, the structure of (CH₃)₂Mg is predicted in Figure A (attached). The A group in the structure represents the solvent. The chemical shift at -1.46 ppm is associated with protons of the bridging methyl groups while the signal at -1.74 ppm is for the proton of the terminal methyl group.
In THF, the two possible structures of (CH₃)₂Mg are predicted in Figure B (attached). Chemical shift at -1.76 ppm is associated with unsolvated monomer of (CH₃)₂Mg while the shift at -1.81 refers to the protons of methyl group bonded to the solvated (CH₃)₂Mg. The solvent is represented as Y in the Figure B.
This study is reported by J. Heard in "NMR of organomagnessium compounds".
A student is carrying out a biological preparation that requires 1 M NaCl to maintain an ionic strength of 1.0. The student chooses to use 1.0 M ammonium sulfate instead. Why is this a serious error?
Explanation:
It is known that the ionic strength of a solution, I, is represented as follows.
[tex]I = \frac{1}{2} \sum m_{i}z^{2}_{i}[/tex]
where, [tex]m_{i}[/tex] = the concentration of the ion,
[tex]z_{i}[/tex] = the charge of the ion
Now, for 1 M NaCl solution, the ionic strength will be calculated as follows.
I = [tex]\frac{1}{2} [(1 \times 1^{2}) + (1 \times 1^{2})][/tex]
= 1.00
And, for 1 M [tex](NH_{4})_{2}SO_{4}[/tex], concentration of [tex][NH_{4}][/tex] = 2 M and [tex][SO_{4}][/tex] = 1 M.
I = [tex]\frac{1}{2} [(2 \times 1^{2}) + ((1 \times 2^{2})][/tex]
= 3.00
As the ionic strength of 1 M [tex](NH_{4})_{2}SO_{4}[/tex], is different therefore it is a serious error.
Using 1.0 M ammonium sulfate instead of 1 M NaCl is a serious error in the biological preparation due to the differences in dissociation and specific properties of the compounds.
Explanation:The student's choice to use 1.0 M ammonium sulfate instead of 1 M NaCl is a serious error because they are not equivalent compounds. Ammonium sulfate dissociates into two ions (NH4+ and SO42-), while NaCl only dissociates into two ions (Na+ and Cl-). Therefore, the ionic strength of the solution will not be the same.
In addition, the presence of different ions in ammonium sulfate will affect the specific properties and behavior of the solution compared to NaCl. For example, the presence of ammonium ions can affect the pH and the precipitation of certain compounds.
It is important to use the correct reagents in a biological preparation to maintain the desired conditions and ensure accurate results.
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If you boil a sample of water, the steam that results will have: Select the correct answer below: less mass than the water more mass than the water the same mass as the water impossible to predict
Answer:
it same mass as water
Explanation:
Final answer:
The steam resulting from boiled water will have the same mass as the water from which it was boiled, adhering to the law of conservation of mass, as long as the system is closed and no mass is lost due to external factors.
Explanation:
When you boil a sample of water, the steam that results will have the same mass as the water if you ignore any minor mass loss due to gases dissolved in water escaping or small amounts of water that may stick to the container. This is because the mass of a substance remains constant during a phase change; only the state of the substance changes from liquid to gas. This is in accordance with the law of conservation of mass.
The mass of a substance does not change as it undergoes physical transformations; thus, when you boil water, all of the mass is converted to steam provided the system is closed and no mass escapes. In an open system, there might be a loss of mass due to external factors, but the boiling process itself does not add or remove mass from the water.
Arrange the following compounds in order of increasing solubility in water: O2, LiCl, Br2, methanol (CH3OH).
The order of increasing solubility in water for O2, Br2, LiCl, and methanol (CH3OH) is: O2 < Br2 < LiCl < Methanol (CH3OH). This is based on whether the molecules are nonpolar or polar and the intermolecular forces present.
Explanation:The solubility of compounds in water ultimate depends on the specific intermolecular interactions. The key principle here is 'like dissolves like', with polar substances dissolving in polar solvents (like water) and nonpolar substances dissolving in nonpolar solvents.
In your list: O2, LiCl, Br2, and methanol (CH3OH), the order of increasing solubility in water would in fact be: O2 < Br2 < LiCl < Methanol (CH3OH)
O2 and Br2 are both nonpolar molecules and hence have a very limited solubility in polar solvents such as water. LiCl is a polar ionic compound, it will easily dissolve in water through ion-dipole interactions. Methanol (CH3OH) is the most soluble because, in addition to being polar, it can form hydrogen bonds with water molecules, which is a stronger intermolecular force. Learn more about Solubility of Compounds here:
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The order of increasing solubility in water is O₂ < Br₂ < LiCl < CH₃OH.
To arrange these compounds in order of increasing solubility in water, we need to consider their polarity and ability to form hydrogen bonds with water. Water is a polar solvent and dissolves polar compounds and ionic compounds well, but non-polar compounds poorly.
O₂ (Oxygen): Non-polar molecule, very low solubility in water.Br₂ (Bromine): Non-polar molecule, low solubility in water, but slightly more soluble than oxygen due to its larger size and polarizability.LiCl (Lithium Chloride): Ionic compound, highly soluble in water due to dissolution into Li+ and Cl- ions.Methanol (CH₃OH): Polar molecule, high solubility in water due to hydrogen bonding with water molecules.Therefore, the order of increasing solubility in water is O₂ < Br₂ < LiCl < CH₃OH.
Calculate the volume in liters of a silver(II) oxide solution that contains mg of silver(II) oxide . Round your answer to significant digits
The question is incomplete, here is the complete question:
Calculate the volume in liters of a [tex]8.75\times 10^{-5}M[/tex] silver (II) oxide solution that contains 200.g of silver (II) oxide . Round your answer to 3 significant digits.
Answer: The volume of solution is [tex]1.84\times 10^4L[/tex]
Explanation:
To calculate the volume of solution, we use the equation used to calculate the molarity of solution:
[tex]\text{Molarity of the solution}=\frac{\text{Mass of solute}}{\text{Molar mass of solute}\times \text{Volume of solution (in L)}}[/tex]
We are given:
Molarity of solution = [tex]8.75\times 10^{-5}M[/tex]
Given mass of silver (II) oxide = 200. g
Molar mass of silver (II) oxide = 124 g/mol
Putting values in above equation, we get:
[tex]8.75\times 10^{-5}M=\frac{200}{124\times \text{Volume of solution}}\\\\\text{Volume of solution}=\frac{200}{124\times 8.75\times 10^{-5}}=1.84\times 10^4L[/tex]
Hence, the volume of solution is [tex]1.84\times 10^4L[/tex]
To calculate the volume in liters of a silver(II) oxide solution, you need to know the amount of the solution in milligrams and the density of the solution. Use the formula Volume (in liters) = x mg / (density in mg/L) and round the final answer to the appropriate number of significant digits.
Explanation:To calculate the volume in liters of a silver(II) oxide solution, we need to know the amount of the solution in milligrams. Let's say the solution contains x mg of silver(II) oxide.
To convert mg to liters, we need to know the density of the solution. Once we have the density, we can use the formula:
Volume (in liters) = x mg / (density in mg/L)
Round the final answer to the appropriate number of significant digits.
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In ionic bonds the atom that contributes an electron and has a positive charge as a result is called the . The atom in ionic bonding that accepts an electron and has a negative charge as a result is called the .
Answer:
a. Cation
b. Anion
Explanation:
I 1 mL o a 0.02% w/v isoproterenol hydrochloride solution is diluted to 10 mL with sodium chloride injection be ore intravenous administration, calculate the percent concentration o the diluted solution
Answer:
0.002% w/v
Explanation:
The unit w/v means that mass (in g) per volume (in mL). When the solution is diluted, the mass of the solvent will not change, and the mass can be calculated by the concentration (C) multiplied by the volume (V). So, if 1 is the initial solution, and 2 the diluted solution:
C1*V1 = C2*V2
C1 = 0.02%
V1 = 1 mL
V2 = 10 mL
0.02*1 = C2*10
10C2 = 0.02
C2 = 0.002% w/v
1-propanol (P1° = 20.9 Torr at 25 °C) and 2-propanol (P2° = 45.2 Torr at 25 °C) form ideal solutions in all proportions. Let x1 and x2 represent the mole fractions of 1-propanol and 2-propanol in a liquid mixture, respectively, and y1 and y2 represent the mole fractions of each in the vapor phase. For a solution of these liquids with x1 = 0.450, calculate the composition of the vapor phase at 25 °C.
y1= y2=
To find the vapor phase composition of a mixture of 1-propanol and 2-propanol at 25 °C, we apply Raoult's Law and Dalton's Law using the given vapor pressures and mole fraction. The calculated vapor phase composition is y1 = 0.2744 for 1-propanol and y2 = 0.7256 for 2-propanol.
The question asks for the composition of the vapor phase at 25 °C for a liquid mixture of 1-propanol and 2-propanol with a given mole fraction of 1-propanol (x1 = 0.450). According to Raoult's Law, the partial pressure of each component in an ideal solution is equal to the mole fraction of the component in the liquid phase times the vapor pressure of the pure component. The total vapor pressure (Ptot) of the solution is the sum of the partial pressures. We can then use Dalton's Law to find the mole fractions of the components in the vapor phase.
To calculate the composition of the vapor phase, we will use the following steps:
Calculate the partial pressure of 1-propanol (P1) using the formula P1 = x1 × P1°, where P1° is the vapor pressure of pure 1-propanol.
P1 = x1 × P1° = 0.450 × 20.9 Torr = 9.405 Torr
Calculate the partial pressure of 2-propanol (P2) using the formula P2 = x2 × P2°, where P2° is the vapor pressure of pure 2-propanol and x2 is the mole fraction of 2-propanol in the liquid phase.
Since the mole fractions must sum to 1,
x2 = 1 - x1 = 1 - 0.450 = 0.550.
Now we calculate P2 = x2 × P2° = 0.550 × 45.2 Torr = 24.86 Torr.
Ptot = P1 + P2 = 9.405 Torr + 24.86 Torr = 34.265 Torr
Calculate the mole fraction of 1-propanol in the vapor phase (y1) using y1 = P1 / Ptot.
y1 = P1 / Ptot = 9.405 Torr / 34.265 Torr = 0.2744
Calculate the mole fraction of 2-propanol in the vapor phase (y2) using y2 = P2 / Ptot.
y2 = P2 / Ptot = 24.86 Torr / 34.265 Torr = 0.7256
Thus, the composition of the vapor phase at 25 °C for the solution with x1 = 0.450 is y1 = 0.2744 and y2 = 0.7256.
Consider that you have a 100 mM stock solution and you need to prepare 10 mL of a 30 mM solution. How many milliliters of the stock solution do you need? mL How many milliliters of deionized water do you need? mL
Answer:
V₁ = 3.0 mL
V(H₂O) = 7 mL
Explanation:
Given data
Initial concentration (C₁): 100 mMInitial volume (V₁): ?Final concentration (C₂): 30 mMFinal volume (V₂): 10 mLIn order to determine the volume of the stock solution, we will use the dilution rule.
C₁ × V₁ = C₂ × V₂
100 mM × V₁ = 30 mM × 10 mL
V₁ = 3.0 mL
The volume of deionized water required is:
V(H₂O) = 10 mL - 3.0 mL = 7 mL
The volume of the stock solution required is 3 mL.
The stock solution is defined as the solution from which other solutions are prepared. We have the following information;
concentration of stock solution = 100 mMConcentration of diluted solution = 30 mM Volume of diluted solution = 10 mLUsing the formula;
M1V1 = M2V2
V1 = M2V2/M1
V1 = 30mM × 10 mL/100 mL
V1 = 3 mL
The volume of the stock solution required is 3 mL.
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The highest concentration of aqueous HCL is ~ 37% by weight, and the density of this solution is 1.18 g/cm3. What is the molarity of HCl of this 37% aqueous HCl solution?
Answer: The molarity of HCl of this 37% aqueous HCl solution is 12.0 M
Explanation:
Given : 37 g of HCl is dissolve in 100 g of solution.
Mass of solute (HCl) = 37 g
Mass of solution = 100 g
Density of solution = 1.18g/ml
Volume of solution =[tex]\frac{\text {mass of solution}}{\text {density of solution}}=\frac{100g}{1.18g/ml}=84.7ml[/tex]
Molarity is defined as the number of moles of solute dissolved per liter of the solution.
[tex]Molarity=\frac{n\times 1000}{V_s}[/tex]
where,
n= moles of solute
[tex]V_s[/tex] = volume of solution in ml = 1000 ml
[tex]moles of solute =\frac{\text {given mass}}{\text {molar mass}}=\frac{37g}{36.5g/mol}=1.01moles[/tex]
Now put all the given values in the formula of molarity, we get
[tex]Molarity=\frac{1.01moles\times 1000}{84.7ml}=12.0mole/L[/tex]
The molarity of HCl solution is 12.0 M
) A 0.907 M lead II nitrate solution has a density of 1.252 g/cm3. Find the molality of the solution.
Answer: The molality of the solution is 0.953 m
Explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution
[tex]Molarity=\frac{n\times 1000}{V_s}[/tex]
where,
n= moles of solute
[tex]V_s[/tex] = volume of solution in ml
Given : 0.907 moles of lead(ii)nitrate is dissolved in 1000 ml of the solution.
density of solution= 1.252 g/ml
Thus mass of solution = [tex]Density\times volume=1.252\times 1000 ml=1252g[/tex]
mass of solute =[tex]moles\times {\text {Molar mass}}=0.907mol\times 331g/mol=300g[/tex]
mass of solvent =mass of solution - mass of solute = (1252-300)g= 952 g
Molality of a solution is defined as the number of moles of solute dissolved per kg of the solvent.
[tex]Molality=\frac{n\times 1000}{W_s}[/tex]
where,
n = moles of solute = 0.907 moles
[tex]W_s[/tex]= weight of solvent in g = 952 g
[tex]Molality = \frac{0.907\times 1000}{952g}=0.953m[/tex]
Thus molality of the solution is 0.953 m
Final answer:
To find the molality of the 0.907 M lead(II) nitrate solution, we first calculate the mass of the solvent in kilograms and then divide the amount in moles of the solute by this mass. The final molality is approximately 0.953 mol/kg.
Explanation:
The question is asking to find the molality of a 0.907 M lead(II) nitrate solution with a density of 1.252 g/cm3. To calculate the molality, we need the number of moles of solute and the mass of the solvent in kilograms.
First, calculate the mass of 1 litre (1000 cm3) of solution using the density:
Mass of solution = Density imes Volume = 1.252 g/cm3 imes 1000 cm3 = 1252 g
Next, the mass of the solute in 1 litre of solution:
Mass of solute = Molarity imes Molar Mass imes Volume = 0.907 mol/L imes 331.2 g/mol imes 1 L = 300.2794 g
Now, find the mass of the solvent (water) by subtracting the mass of solute from the total mass of the solution:
Mass of solvent = Mass of solution - Mass of solute = 1252 g - 300.2794 g = 951.7206 g
Convert mass of solvent to kilograms:
Mass of solvent (kg) = 951.7206 g imes (1 kg / 1000 g) = 0.9517206 kg
Finally, calculate the molality (m):
Molality (m) = Moles of solute / Mass of solvent (kg) = 0.907 mol / 0.9517206 kg = 0.953 m
Therefore, the molality of the lead(II) nitrate solution is approximately 0.953 mol/kg.
A chemist prepares a solution of silver perchlorate by measuring out of silver perchlorate into a volumetric flask and filling the flask to the mark with water. Calculate the concentration in of the chemist's silver perchlorate solution. Round your answer to significant digits.
To calculate the concentration of a solution, moles of solute are divided by the final volume in liters. Without the specific mass of silver perchlorate, we cannot determine the concentration of the solution.
Explanation:To calculate the concentration of the chemist's silver perchlorate solution, we need to know the mass of silver perchlorate used and the final volume of the solution. The details of the mass have been omitted from the question, but typically, you would use the molar mass of silver perchlorate to determine the number of moles. To prepare a solution of desired concentration, the chemist would dissolve silver perchlorate in a volumetric flask and add water to the mark, ensuring the final volume accounts for the space occupied by the dissolved solute.
Once a known mass of silver perchlorate is dissolved to make a known final volume, the molarity (M) can be calculated by dividing the number of moles of silver perchlorate by the final volume of the solution in liters. For example, if we dissolved 50 grams of silver perchlorate and the molar mass is X g/mol, we would first calculate the moles as 50 g / X g/mol. Then if the final volume of the solution is 1 L, the concentration would be 50 g / X g/mol / 1 L = Y M.
If the question had provided specific values, we would use them in the calculation and round the answer to the appropriate number of significant digits. However, without the exact mass of silver perchlorate used, we cannot complete this calculation.
A block of substance has a width of 3.8 cm, a length of 8.2 cm, and height of 7 cm . Its mass is 0.68 kg. Calculate the density of the substance.
Answer:
d = 3.11 g /cm³
Explanation:
Volume -
The volume of a cuboidal object can be calculated by multiplying the length , width and height ,
Hence , Volume ( V ) = l * w * h ,
From the question ,
l = 8.2 cm
w = 3.8 cm
h = 7 cm
Hence, the volume is ,
V = l * w * h
V = 8.2 cm * 3.8 cm * 7 cm
V = 218.12 cm³
Density -
Density of a substance is given as the mass divided by the volume ,
Hence,
d = m / V
From the question,
m = 0.68 kg
since ,
1 kg = 1000g
m = 0.68 * 1000 = 680 g
V = 218.12 cm³ ( calculated above )
Hence , the value of density can be calculated by using the above equation,
d = m / V
d = 680 g / 218.12 cm³
d = 3.11 g /cm³
Fracking involves the ______drilling to extract oil and natural gas from the rock. Select one: a. vertical b. lateral c. horizonta
Answer:
Fracking involves the ______drilling to extract oil and natural gas from the rock. Select one: a. vertical b. lateral c. horizontal
The answer is option C (horizontal)
Explanation:
Fracking commonly known as Hydraulic fracturing is an oil and gas production technique that has enabled the extraction of oil and gas from rock (shale rock).
A fracturing fluid typically water with additives is pumped under high pressure into the drilling pipe to widen fractures in the rock or to create new ones and and allow trapped gas or crude oil to flow through a pipe to a wellhead at the surface, deep holes are drilled down into the shale rock. These fractures are held open by an injected proppant, typically sand and release hydrocarbons. Fracking takes about three to five days. Since shale reserves are typically distributed horizontally rather than vertically, horizontal directional drilling method is employed.
Some of the impacts of Fracking on the environment are:
It consume large quantities of fresh waterThe injection of recovered fracking water into underground disposal wells and the high pressure used to extract oil and gas from rock may cause earthquakes.Fracking causes air and water pollution.Deforestation caused by fracking has deep effects on the environment.Fracking, or hydraulic fracturing, primarily involves horizontal drilling. Starting vertically, the drill transitions to a horizontal path to enhance contact with gas or oil-bearing rocks, thereby improving extraction efficiency.
Explanation:Fracking, also known as hydraulic fracturing, involves the horizontal drilling to extract oil and natural gas from the rock. The process begins with a vertical hole that reaches the desired depth and then transitions into lateral or horizontal drilling. This allows for increased contact with the oil or gas-bearing rock, improving the extraction process and its efficiency.
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g An example of an element is ____.
a) chicken noodle soup
b) powerade
c) air inside a balloon
d) lead pipe
e) baking soda (NaHCO)
For a certain chemical reaction, ΔH∘=−156kJ. Assuming the reaction is at equilibrium, classify each of the following actions by whether it causes a leftward shift, a rightward shift, or no shift in the direction of the net reaction.
a. Increase the temperature.
b. Decrease the temperature.
Explanation:
As per Le Chatelier's principle, any disturbance caused in an equilibrium reaction will tend to shift the equilibrium in a direction away from the disturbance.
Since, the given reaction is exothermic in nature so, when we increase the temperature then reaction will shift in the direction opposing the increase in temperature. Hence, the equilibrium will shift on left side when we increase the temperature.
On the other hand, when we decrease the temperature then the equilibrium will shift on the right side.
The correct classifications for the actions based on the given are as follows:
a. Increase the temperature: This causes a rightward shift in the direction of the net reaction.
b. Decrease the temperature: This causes a leftward shift in the direction of the net reaction.
For a chemical reaction at equilibrium, Le Chatelier's Principle states that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium moves to counteract the change.
The reaction in question has a standard enthalpy change of 156 kJ, which indicates that the reaction is exothermic (releases heat).
a. Increase the temperature:
When the temperature is increased for an exothermic reaction, the system tries to absorb the excess heat to restore equilibrium. Since the forward reaction releases heat, the system will favor the reverse reaction to absorb heat. However, because the forward reaction is exothermic and already releases heat, increasing the temperature actually provides energy to the system, which drives the reaction forward to consume the added energy. Therefore, increasing the temperature causes a rightward shift in the direction of the net reaction.
b. Decrease the temperature:
Conversely, when the temperature is decreased, the system tries to release heat to restore equilibrium. For an exothermic reaction, the forward reaction releases heat, so decreasing the temperature will favor the forward reaction to release heat and restore equilibrium. Therefore, decreasing the temperature causes a leftward shift in the direction of the net reaction, favoring the products since the forward reaction is exothermic and will release heat.
In summary, for an exothermic reaction, increasing the temperature will shift the equilibrium to the right (towards the products), and decreasing the temperature will shift the equilibrium to the left (towards the reactants).
Calculate the theoretical oxygen demand (mg/L). of a solution containing 450mg of glucose (C6H12O6). in 2 L of distilled water.
Answer:
ThOD =239.792 mg/L
Explanation:
Theorical Oxigen demand (ThOD):
is the theoretical amount of oxygen
required to oxidize the organic fraction of a
waste up to carbon dioxide and water.
⇒ C sln = 450 mg C6H12O6 / 2 L H2O = 225 mg/L sln
∴ mm C6H12O6 = 180.156 g/mol
balanced reaction:
C6H12O6 + 6O2 → 6CO2 + 6H2O∴ mol C6H12O6 = 1 mol
⇒ mass C6H12O6 = (180.156 g/mol)( 1 mol) = 180.156 g
∴ the value of ThOD is determined when 180.156 g C6H12O6 consume mass O2 = 6(32) = 192 g Oxygen; then in a solution of 225 mg/L, you have:
⇒ ThOD = (192/180.156)×225 mg/L
⇒ ThOD = 239.792 mg/L
The theoretical oxygen demand is 0.24 g/L or 240mg/L.
To calculate the theoretical oxygen demand of a solution containing 450mg of glucose (C6H12O6) in 2 L of distilled water, we need to start by determining the stoichiometry of the complete combustion of glucose, which can be represented by the balanced chemical equation:
C6H12O6 + 6O2 → 6CO2 + 6H2O
From the equation, we can see that 1 mole of glucose requires 6 moles of oxygen to completely react. Therefore, to calculate the oxygen demand, we first need to find the number of moles of glucose present in the solution:
The molar mass of glucose (C6H12O6) is approximately 180 g/mol. So, 450 mg of glucose is equal to 0.450 g or 0.450/180 = 0.0025 moles of glucose.
Using the stoichiometry from the equation, the moles of oxygen required is 0.0025 moles of glucose imes 6 moles of oxygen/mole of glucose = 0.015 moles of oxygen.
Now, the molar mass of oxygen (O2) is approximately 32 g/mol, hence 0.015 moles imes 32 g/mol = 0.48 grams of oxygen. Since the solution volume is 2 L, we need to find the amount per liter, which gives us 0.48 g / 2 L = 0.24 g/L or 240 mg/L of theoretical oxygen demand.
Based on the standard free energies of formation, which of the following reactions represent a feasible way to synthesize the product?A. 2C(s)+H2(g)→C2H2(g); ΔG∘f=209.2 kJ/molB. N2(g)+3H2(g)→2NH3(g); ΔG∘f=−33.30 kJ/molC. 2C(s)+2H2(g)→C2H4(g); ΔG∘f=68.20 kJ/molD. 2SO(g)+O2(g)→2SO2(g); ΔG∘f=−600.4 kJ/mol
Answer:
Option B and D
Explanation:
The Gibb's free energy also referred to as the gibb's function represented with letter G. it is the amount of useful work obtained from a system at constant temperature and pressure. The standard gibb's free energy on the other hand is a state function represented as Delta-G, as it depends on the initial and final states of the system.
A feasible way to synthesize the product entails the spontaneity of the reaction.
The spontaneity of a reaction is explained by the standard gibb's free energy.
If Delta-G = -ve ( the reaction is spontaneous)
if Delta -G = +ve ( the reaction is non-spontaneous)
if Delta-G = 0 ( the reaction is at equilibrium)
Hence the option (B and D) with negative Gibb's free energy are the reaction that are spontaneous.
Student measured the absorbance of substance X in aqueous solution depending on concentration. He used 0.5 cm cuvette for his measurements; concentration was expressed in moles/L and plotted on x-axis, while absorbance was on y-axis. His data were best fitted by the straight line with equation y = 2120x + 0.0112. The extinction coefficient for substance X in aqueous solution is:
Answer:
The extinction coefficient is 4240 M⁻¹cm⁻¹
Explanation:
The Beer-Lambert law for the absorbance of a monochromatic light by a molecule is given by the following mathematical expression:
[tex]A=EbC[/tex]----------------------(1)
Here, E is the extinction coefficient, b is the length of light pathway through the solution and C is the concentration in mol/L. This is a linear equation and fits well with its formula
y = mx + C-------------------(2)
Here, m is the slope and C is the y intercept. y and x are the two variables. Comparing equation 1 and 2, Absorbance (A) and molar concentration (C) are the two variables, while the product of extinction coefficient (E) and path length (b) makes the slope of the line. The y-intercept in the given equation is due to the solvent interference.
From this information, we can determine the extinction coefficient by the slope of the line with the following formula.
[tex]m=Eb[/tex]
[tex]E=\frac{2120 (M^{-1} )}{0.5(cm)}[/tex]
[tex]E= 4240 M^{-1}cm^{-1}[/tex]
Given the reactions below, answer the following questions.
Cl_2(g) + F_2(g) rlhar 2ClF(g) delta G degree_rxn = 115.4 kJ/mol
Cl_2(g) + Br_2(g) rlhar 2ClBr(g) delta G degree_rxn = -2.0 kJ/mol
Calculate the delta G degree_rxn for 2ClF(g) + Br_2(g) rlhar 2ClBr(g) + F_2(g) __________ kJ/mol
Answer:
[tex]\Delta G_{rxn}^{0}=-117.4kJ/mol[/tex]
Explanation:
Gibbs free energy is an additive property.
[tex]2ClF(g)\rightarrow Cl_{2}(g)+F_{2}(g)[/tex] ; [tex]\Delta G_{1}^{0}=-115.4kJ/mol[/tex]
[tex]Cl_{2}(g)+Br_{2}(g)\rightarrow 2ClBr(g)[/tex] ; [tex]\Delta G_{2}^{0}=-2.0kJ/mol[/tex]
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[tex]2ClF(g)+Br_{2}(g)\rightarrow 2ClBr(g)+F_{2}(g)[/tex] ; [tex]\Delta G_{rxn}^{0}=\Delta G_{1}^{0}+\Delta G_{2}^{0}=(-115.4-2.0)kJ/mol=-117.4kJ/mol[/tex]
So, standard gibbs free enrgy change for the given reaction is -117.4 kJ/mol
The change in free energy is called G (∆G). The [tex]\rm \Delta G^\circ rxn= -117.4\; kj/mol[/tex]
What is Gibbs free energy?Gibb free energy is the measure of the maximum amount of reversible work done in a thermodynamic system.
It means only when the temperature change, but the pressure is constant.
[tex]\rm Cl_2(g) + F_2(g) \longrightarrow 2ClF(g) \;delta\; G\;degree_rxn = 115.4 kJ/mol[/tex]
[tex]\rm Cl_2(g) + Br_2(g) \longrightarrow 2ClBr(g) \;delta\; G \;degree_r_x_n = -2.0 kJ/mol[/tex]
[tex]\rm \Delta G^\circ rxn= \Delta G^\circ1 +G^\circ2[/tex]
[tex]2ClF(g) + Br_2(g) \longrightarrow 2ClBr(g) + F_2(g)[/tex]
[tex]\rm \Delta G^\circ rxn= -115.4\;kj/mol - 2.0 \;kj/mol = -117.4\;kj/mol[/tex]
Thus, the [tex]\rm \Delta G^\circ rxn= -117.4\; kj/mol[/tex].
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Sometimes, as we learned in this lesson, a single Lewis structure does not describe a molecule, and it instead resonates between two or more structures. What symbol do we place between these structures to show this?
A. ←
B. ≡
C. ↔
D. →
Answer:
C. ↔
Explanation:
Resonating structure -
These are the set of lewis structures of the same compound .
Where the structure helps to show the delocalization of the electrons over the structure .
The charge on all the resonating structure remains the same .
All the structures can be interconverted to each other , and are shown by the arrow ↔ .
Hence , from the given information of the question,
The correct option is C. ↔
By titration, 15.0 mL of 0.1008 M sodium hydroxide is needed to neutralize a 0.2053-g sample of an organic acid. What is the molar mass of the acid if it is monopro-tic
Answer: The molar mass of monoprotic acid is 135.9 g/mol
Explanation:
To calculate the number of moles for given molarity, we use the equation:
[tex]\text{Molarity of the solution}=\frac{\text{Moles of solute}\times 1000}{\text{Volume of solution (in mL)}}[/tex]
Molarity of NaOH solution = 0.1008 M
Volume of solution = 15.0 mL
Putting values in above equation, we get:
[tex]0.1008M=\frac{\text{Moles of NaOH}\times 1000}{15.0}\\\\\text{Moles of NaOH}=\frac{(0.1008\times 15.0)}{1000}=0.00151mol[/tex]
As, the acid is monoprotic, it contains 1 hydrogen ion
1 mole of [tex]OH^-[/tex] ion of NaOH neutralizes 1 mole of [tex]H^+[/tex] ion of monoprotic acid
So, 0.00151 moles of [tex]OH^-[/tex] ion of NaOH will neutralize [tex]\frac{1}{1}\times 0.00151=0.00151mol[/tex] of [tex]H^+[/tex] ion of monoprotic acid
Moles of monoprotic acid = 0.00151 moles
To calculate the number of moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]
Moles of monoprotic acid = 0.00151 mole
Given mass of monoprotic acid = 0.2053 g
Putting values in above equation, we get:
[tex]0.00151mol=\frac{0.2053g}{\text{Molar mass of monoprotic acid}}\\\\\text{Molar mass of monoprotic acid}=\frac{0.2053g}{0.00151mol}=135.9g/mol[/tex]
Hence, the molar mass of monoprotic acid is 135.9 g/mol
The molar mass of the monoprotic acid, which can be calculated using the titration method with sodium hydroxide, was found to be approximately 135.7 g/mol.
Explanation:The subject of your query concerns on calculating the molar mass of an organic acid using the titration method with known information about sodium hydroxide. First, we need to look into the moles of sodium hydroxide (NaOH) used. Since we know the volume V=15.0 mL and concentration C=0.1008 M of NaOH used, moles (n) can be calculated using the equation n=CV, converting volume to liters, gives n = 0.1008 mol/L * 0.015 L = 0.001512 mol.
Because the sodium hydroxide and monoprotic acid react in a 1:1 ratio (as given by the neutralization equation NaOH + HA -> NaA + H2O), the moles of acid are also 0.001512.
The molar mass of the substance can then be determined by dividing the given mass of the sample by the number of moles. The mass of the organic acid is 0.2053g, so the molar mass (M) is M = mass / n = 0.2053g / 0.001512 mol = 135.7 g/mol.
This means that the molar mass of the monoprotic organic acid is approximately 135.7 g/mol.
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A student dissolves 3.9g of aniline (C6H5NH2) in 200.mL of a solvent with a density of 1.05 g/mL . The student notices that the volume of the solvent does not change when the aniline dissolves in it. Calculate the molarity and molality of the student's solution. Be sure each of your answer entries has the correct number of significant digits. X10 How do I enter a number in scientific notation? molarity = x10 molarity=
Answer:
2.1 × 10⁻¹ M
2.0 × 10⁻¹ m
Explanation:
Molarity
The molar mass of aniline (solute) is 93.13 g/mol. The moles corresponding to 3.9 g are:
3.9 g × (1 mol/93.13 g) = 0.042 mol
The volume of the solution is 200 mL (0.200 L). The molarity of aniline is:
M = 0.042 mol/0.200 L = 0.21 M = 2.1 × 10⁻¹ M
Molality
The moles of solute are 0.042 mol.
The density of the solvent is 1.05 g/mL. The mass corresponding to 200 mL is:
200 mL × 1.05 g/mL = 210 g = 0.210 kg
The molality of aniline is:
m = 0.042 mol/0.210 kg = 0.20 m = 2.0 × 10⁻¹ m
Under what conditions does an increase in temperature turn a nonspontaneous process into a spontaneous process?
Choose one or more:
a. ΔH < 0, ΔS > 0
b. ΔH > 0, ΔS > 0
c. ΔH > 0, ΔS < 0
d. ΔH < 0, ΔS < 0
(What I'm trying to figure out is if you need to consider T being negative OR positive to start)
Answer:ΔH < 0, ΔS > 0
Explanation:
Consider ∆G= ∆H-T∆S
If ∆H is negative and and ∆S is positive, when T is increased, T∆S becomes more positive until the result of the difference between ∆H-T∆S becomes negative. Remember that a reaction is only spontaneous when ∆G is negative. Hence under these conditions, ∆G becomes negative and the reaction becomes spontaneous.
The dissolving of ammonium nitrate is often used in an instant cold pack used to relieve swelling.
If this process is an endothermic reaction, i.e. absorbs heat, then why does it feel cold to the touch instead of hot?
Answer:
Here's what I get
Explanation:
Does an ice cube feel cold to the hand?
The melting of ice is an endothermic process.
If you hold an ice cube, heat flows from your hand to the ice. When your hand loses heat, it feels cold.
In the same way, the endothermic dissolving of ammonium nitrate removes the heat from your hand, so the pack feels cold.
Classify each of the following particulate level illustrations as a representation of either a pure substance, a homogeneous mixture, or a heterogeneous mixture.Figure:three compounds were drawn
Answer:
The classification and illustrations are attached in the drawing.
Explanation:
It is possible to identify the pure substance observing the figure, since it is the only one that has 2 joined atoms (purple and blue) which forms a single compound.
On the other hand, the homogeneous mixture is identified by noting that its atoms are more united with respect to the heterogeneous mixture, highlighting that in homogenous mixtures the atoms, elements or substances are not visible to the naked eye and are in a single phase, instead in the heterogeneous mixture if they can be differentiated.
Heterogeneous mixture: Visible multiple chemicals with distinct parts.
Homogeneous mixture: Appears as one material, uniform with indistinguishable atoms and elements.
Pure material distinguished by figure with linked blue and purple atoms forming a single compound.
Heterogenous combination of visible compounds. Homogenous mixture comprised of various materials that seem like one substance Each sample portion has the same makeup and properties. The graphic shows that the pure material is the only one with two connected atoms (blue and purple) that form a compound.
The homogeneous mixture is distinguished by its more unified atoms, emphasizing that while in homogeneous mixtures the atoms, elements, and substances are not visible to the eye and are in a single phase, in the heterogeneous mixture they can be distinguished.
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Write the following numbers in standard notation, maintaining the same number of significant figures.
6.104 x10^2
9.5 x 10^-3
Move the decimal by a certain number of spaces, according to the exponent of 10
Answer:
6.104x10^2=610.4
9.5x10^3=9500
Explanation:
To convert from scientific notation (6.104 x10^2, 9.5 x 10^-3) to standard notation, move the decimal point in accordance with the power of 10 (right for positive, left for negative). The converted numbers become 610.4 and 0.0095, respectively.
Explanation:In scientific notation, the base number is expressed as a decimal between 1 and 10, and tens are represented by powers of 10. In standard notation, we write the number in usual decimal representation.
To convert 6.104 x10^2 to standard notation, move the decimal two places to the right (because the exponent is positive), giving you 610.4.
For 9.5 x 10^-3, move the decimal three places to the left (because the exponent is negative). So, it becomes 0.0095.
Remember that the number of significant figures must remain the same when converting to standard notation.
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Calculate the solubility of carbon dioxide in water at an atmospheric pressure of 0.400 atm (a typical value at high altitude).
Answer:
1.40*10⁻² M
Explanation:
We have the solubility formula
Solubility,
S = KH*P
where
KH = measure of hardness of water / carbonate hardness = 3.50*10⁻² mol/L.atm
P = atmospheric pressure = 0.400 atm
Hence, we have
S = KH*P
= (3.50*10⁻² mol/L.atm)*(0.400 atm)
= 1.40*10⁻² mol/L
But 1 mol/L = 1 M,
Hence, the answer (1.40*10⁻² mol/L ) is equivalent to
= 1.40*10⁻² M
If you are asked to make 40 mL of a 1.0% (w/v %) agarose gel, how many grams of agarose will you add to the 40ml of buffer
Answer:
0.4g
Explanation:
1.0% (w/v%) = 1 g of agarose 100 ml of Tris-Acetate-EDTA, this is the buffer that agarose is run with
the amount of agarose for 40 ml = 1 /100 × 40 ml = 0.4 g
Final answer:
To prepare 40 mL of a 1.0% (w/v %) agarose gel, measure and mix 0.4 grams of agarose powder with 40 mL of buffer solution in an Erlenmeyer flask.
Explanation:
If you are asked to make 40 mL of a 1.0% (w/v %) agarose gel, you will add 0.4 grams of agarose to the 40 mL of buffer. To made this calculation, you need to understand the meaning of w/v %, which stands for weight/volume percentage. It is defined as the mass of a solute (in this case agarose powder) divided by the volume of the solution, and then multiplied by 100 to get the percentage.
For a 1.0% (w/v %) agarose gel, this means that you need 1 gram of agarose powder for every 100 mL of solution. Therefore, for 40 mL of solution, you simply use the proportion:
1 gram/100 mL = X grams/40 mL
Solving for X gives you:
X = (1 gram/100 mL) * 40 mL = 0.4 grams
Conclusion: To prepare a 40 mL agarose gel at 1.0% w/v concentration, weigh out 0.4 grams of agarose powder using an electronic scale, and then blend it with the appropriate buffer in an Erlenmeyer flask.
Consider the reaction data. A ⟶ products A⟶products T ( K ) T (K) k ( s − 1 ) k (s−1) 225 225 0.391 0.391 525 525 0.700 0.700 What two points should be plotted to graphically determine the activation energy of this reaction? To avoid rounding errors, use at least three significant figures in all values.
Answer:
The activation energy for the reaction is, 1.90682 KJ/mol.
Explanation:
According to the Arrhenius equation,
[tex]K=A\times e^{\frac{-Ea}{RT}}[/tex]
or,
[tex]\log (\frac{K_2}{K_1})=\frac{Ea}{2.303\times R}[\frac{1}{T_1}-\frac{1}{T_2}][/tex]
where,
[tex]K_1[/tex] = rate constant at 225 K = [tex]0.391 s^{-1}[/tex]
[tex]K_2[/tex] = rate constant at 525 K = [tex]0.700 s^{-1}[/tex]
[tex]Ea[/tex] = activation energy for the reaction = ?
R = gas constant = 8.314 J/mole.K
[tex]T_1=225 K, T_2=525 K[/tex]
Now put all the given values in this formula, we get
[tex]\log (\frac{0.700 s^{-1}}{0.391 s^{-1}})=\frac{Ea}{2.303\times 8.314J/mole.K}[\frac{1}{225 K}-\frac{1}{525 K}][/tex]
[tex]Ea=1,906.82 J/mole=1.90682 KJ/mol[/tex]
Therefore, the activation energy for the reaction is, 1.90682 KJ/mol.
How much work would it take to push two protons very slowly from a separation of 2.00×10−10m (a typical atomic distance) to 3.00×10−15m (a typical nuclear distance)?
Answer: 7.68×10^14 J
Explanation:
The magnitude of the charge q1=q2 = 1.6×10^-19 C
Proportionality constant K = 9×10^9 Nm²/C²
Da= 2×10^-10m
Db= 3 ×10^-15m
W= k q1q2 ( 1/Db -1/Da)
W= 9×10^9 (1.69×10^-19)²(1/3.0×10^-15 - 1/2×10^-10)
W= 7.68 ×10^-14J
Therefore the amount of work requires is 7.68 ×10^-14J