Answer: Thus the cell potential of an electrochemical cell is +0.28 V
Explanation:
The calculation of cell potential is done by :
[tex]E^0=E^0_{cathode}- E^0_{anode}[/tex]
Where both [tex]E^0[/tex] are standard reduction potentials.
[tex]E^0_{[Fe^{2+}/Fe]}= -0.41V[/tex]
[tex]E^0_{[Pb^{2+}/Pb]}=-0.13V[/tex]
As Reduction takes place easily if the standard reduction potential is higher(positive) and oxidation takes place easily if the standard reduction potential is less(more negative). Thus iron acts as anode and lead acts as cathode.
[tex]E^0=E^0_{[Pb^{2+}/Pb]}- E^0_{[Fe^{2+}/Fe]}[/tex]
[tex]E^0=-0.13- (-0.41V)=0.28V[/tex]
Thus the cell potential of an electrochemical cell is +0.28 V
Assume that a nickel weighs exactly 5.038650 g for the sets of weights listed below obtained by a single weighing on the balance below
Answer:
afshkkyfugutuiryfyi
Compound X absorbs photons with a wavelength of 179.3 nm. What is the increase in energy of a 0.115 M solution of compound X in which a mole of photons are absorbed
Answer:
Explanation:
one mole of photon will contain
6.02 x 10²³ no of photons
energy of one photon = h x f
= h c / λ
h is plank's constant , c is velocity of light and λ is wavelength
= 6.6 x 10⁻³⁴ x 3 x 10⁸ / 179.3 x 10⁻⁹
= .11 x 10⁻¹⁷ J
energy of one mole of photon
= 6.02 x 10²³ x .11 x 10⁻¹⁷
= .6622 x 10⁶ J
What mass of Si, in grams, can be produced from the reaction below starting with 225 g SiCl4 and 101 g Mg? SiCl4 + Mg Si + MgCl2 Given: 1 mol SiCl4 = 169.8963 g SiCl4 1 mol Mg = 24.3050 g Mg 1 mol Si = 28.0855 g Si
Answer:
[tex]m_{Si}=37.2gSi[/tex]
Explanation:
Hello,
In this case, for the undergoing balanced chemical reaction:
[tex]SiCl_4 + 2Mg \rightarrow Si + 2MgCl_2[/tex]
We must first identify the limiting reactant given the 225 g of SiCl4 and 101 g of Mg. Thus, we compute the available moles of SiCl4:
[tex]n_{SiCl_4}=225gSiCl_4*\frac{1molSiCl_4}{169.8963gSiCl_4}=1.324molSiCl_4[/tex]
Next, by using the 1:2 mole ratio between SiCl4 and Mg, we compute the moles of SiCl4 consumed by 101 g of Mg:
[tex]n_{SiCl_4}^{consumed}=101gMg*\frac{1molMg}{24.3050gMg} *\frac{1molSiCl_4}{2molMg} =2.08molSiCl_4[/tex]
Thus, since less moles of SiCl4 are available, we can infer it is the limiting reactant whereas the Mg is in excess. In such a way, the produced grams of Si are computed considering the 1:1 molar ratio between SiCl4 and Si:
[tex]m_{Si}=1.324molSiCl_4*\frac{1molSi}{1molSiCl_4} *\frac{28.0855gSi}{1molSi} \\\\m_{Si}=37.2gSi[/tex]
Best regards.
Identify the Lewis acid and Lewis base from among the reactants in each of the following equations. Match the words in the left column to the appropriate blanks in the sentences on the right.
1. Fe3+ (aq)+6CN (aq) Fe(CN) (aq)______is the Lewis acid and_____is the Lewis base. is the Lewis
2. CI- (aq) + AlCl3 (aq) AlCl4-____is the Lewis acid and______is the Lewis base.
3. AlBr3 + NH3 H3NAlBr3______is the Lewis acid and______is the Lewis base.
A. AlCl3
B. CN-
C. AlBr3
D. Cl-
E. NH3
F. Fe3+
Answer:
1. Lewis acid: F. Fe₃⁺, Lewis base: B. CN⁻
2. Lewis acid: A. AlCl₃, Lewis base: D. Cl⁻
3. Lewis acid: C. AlBr₃, Lewis base: E. NH₃
Hope this helps.
The Lewis acid is chemical substance which possesses an empty orbital and accepts an electron pair from a Lewis base ( donor ), in order to create a Lewis adduct ( molecule created from the bonding of Lewis base and acid ).
The Lewis acid from reaction 1 is Fe₃⁺ while the Lewis base is CN⁻ also the Lewis acid from reaction 2 is AICI₃ while the Lewis base is CI⁻
Hence we can conclude that the Lewis acids and Lewis bases of the reactions in the question are as listed above.
Learn more: https://brainly.com/question/16108775
Solid sodium oxide and gaseous water are formed by the decomposition of solid sodium hydroxide (NaOH) .
Write a balanced chemical equation for this reaction.
Answer:
2NaOH(s) → Na₂O(s) + H₂O(g)
Hope that helps.
Does the number of moles of products increase, decrease, or remain the same when each of the following equilibria is subjected to an increase in pressure by decreasing the volume?
1- CO(g)+H2O(g)⇌CO2(g)+H2(g)
2- 2CO(g)⇌C(s)+CO2(g)
3- N2O4(g)⇌2NO2(g)
_______________________________________________
Ethyl acetate, a solvent used in many fingernail-polish removers, is made by the reaction of acetic acid with ethanol:
CH3CO2H(soln)Aceticacid +C2H5OH(soln)Ethanol⇌CH3CO2H(soln)Ethylacetate+H2O(soln)ΔH∘=−2.9kJ
Part A
Does the amount of ethyl acetate in an equilibrium mixture increase or decrease when the temperature is increased?
increase
decrease
Part B
How does Kc change when the temperature is decreased? Justify your answers using Le Chatelier's principle.
How does change when the temperature is decreased? Justify your answers using Le Chatelier's principle.
As the temperature is decreased, the reaction shifts from left to right. The product concentrations increase, and the reactant concentrations decrease. This corresponds to an increase in Kc.
As the temperature is decreased, the reaction shifts from right to left. The product concentrations decrease, and the reactant concentrations increase. This corresponds to an decrease in Kc.
As there is neither products no reactants in gas state the temperature does not shift the reaction. So decrease in temperature does not change Kc.
________________________________________________________
A platinum catalyst is used in automobile catalytic converters to hasten the oxidation of carbon monoxide:
2CO(g)+O2(g)⇌Pt2CO2(g)ΔH∘=−566kJ
Suppose that you have a reaction vessel containing an equilibrium mixture of CO(g), O2(g), and CO2(g). Under the following conditions, will the amount of CO increase, decrease, or remain the same after each of the following changes?
A platinum catalyst is added.
increase
decrease
remain the same
The temperature is increased.
increase
decrease
remain the same
The pressure is increased by decreasing the volume.
increase
decrease
remain the same
The pressure is increased by adding argon gas.
increase
decrease
remain the same
The pressure is increased by adding gas.
increase
decrease
remain the same
Answer:
1-remain the same
2- remain the same
3-decrease
--------------------------
- decrease
- As the temperature is decreased, the reaction shifts from left to right. The product concentrations increase, and the reactant concentrations decrease. This corresponds to an increase in Kc.
--------------------------------
1- decrease
2-increase
3-decrease
4-remain the same
5-decrease
Explanation:
According to Le Chateliers principle, an increase in the volume of a gaseous system at equilibrium will shift the equilibrium position towards the side in which there are less volumes. Hence the answers written. When there is no change in volume, the number of moles of products remain the same.
-------------------------------
For an exothermic reaction, increasing the temperature shifts the equilibrium to the lefthand side.
When temperature is decreased, the equilibrium position will shift towards the right according to Le Chateliers principle
---------------------
Addition of a catalyst aids the reaction in which CO is consumed to proceed faster hence CO decreases in the system.
Since the reaction is exothermic, according to Le Chateliers principle, when the temperature is increased, the equilibrium position shifts towards the lefthand side and more CO is now present in the system.
When the pressure of the system is increased, the equilibrium position will shift towards the right hand side and more CO is converted to products hence its concentration in the system decreases.
Addition of argon gas has no effect on the equilibrium position since it does not participate in the reaction. However, addition of the reactant gases increases the rate of reaction and shifts the equilibrium position towards the right hand side thus decreasing the concentration of CO in the system.
Calculate the quantity of energy produced per gram of U-235 (atomic mass = 235.043922 amu) for the neutron-induced fission of U-235 to form Xe-144 (atomic mass = 143.9385 amu) and Sr-90 (atomic mass = 89.907738 amu). Express your answer in joules per gram to three significant figures.
Answer:
To calculate the amount of energy produced per gram from Uranium- 235 we call on the formula:
delta(m)= mass of the products - mass of reactants
Given the atomic mass of Xe-144 = 143.9385 amu; atomic mass of Sr-90= 89.907738 amu; atomic mass of U-235= 235.043922 amu
Therefore:
delta(m)= (143.9385 + 89.907738) - (235.043922) = -1.197682 amu
Recall that to calculate energy in joules, we use the formula:
Energy = mc^2
Therefore: Energy = (-1.197582/6.022 x 10^26)kg x (3 x 10^8 m/s)^2
= -1.7898104 x 10^-10 J
= (-1.7898104 x 10^-10 x 6.022 x 10^23/235.043922)
= -4.586 x 10^11 J per gram of energy released
Explanation:
To calculate the amount of energy produced per gram from Uranium- 235 we call on the formula:
delta(m)= mass of the products - mass of reactants
Given the atomic mass of Xe-144 = 143.9385 amu; atomic mass of Sr-90= 89.907738 amu; atomic mass of U-235= 235.043922 amu
Therefore:
delta(m)= (143.9385 + 89.907738) - (235.043922) = -1.197682 amu
Recall that to calculate energy in joules, we use the formula:
Energy = mc^2
Therefore: Energy = (-1.197582/6.022 x 10^26)kg x (3 x 10^8 m/s)^2
= -1.7898104 x 10^-10 J
= (-1.7898104 x 10^-10 x 6.022 x 10^23/235.043922)
= -4.586 x 10^11 J per gram of energy released
Draw the curved arrow mechanism for the reaction between (2R,3R)-3,5-dimethylhexan-2-ol and PCl3.
Answer:
Sn2 mechanism
Explanation:
In this case, our nucleophile is the "OH" on (2R,3R)-3,5-dimethylhexan-2-ol. The alcohol group will attack the [tex]PCl_3[/tex] to produce a new bond between O and P with a positive charge in the oxygen. Additionally, when the OH attacks a Br atom leaves the molecule producing a bromide ion.
In the next step, the bromide ion produced will attack the carbon bonded to the OH that now is bonded to [tex]PCl_2[/tex]. An Sn2 reaction takes place and the substitution would be made in only one step. Due to this, we will have an inversion in the stereochemistry and the absolute configuration on carbon 2 will change from "R" to "S" to produce (2S,3R)-2-bromo-3,5-dimethylhexane.
I hope it helps!
Determine if each of the following statements about chiral molecules is True or False and select the best answer from the dropdown menus.
True or False: All R stereocenters are dextrorotatory.
True or False: Chiral centers in organic molecules will have 4 different groups attached to a carbon.
True or False: A racemic mixture has an optical activity of 0.
True or False: Normal linear amines can be chiral centers.
True or False: Compound C has an optical activity of 0.
True or False: If the R isomer of a molecule has an optical rotation of + 25.7 degree then the S isomer of the molecule will have an optical rotation of -25.7 degree.
True or False: A CN is higher priority than a CH2OH.
True or False: All molecules with chiral centers are optically active.
True or False: To have an enantiomer a molecule must have at least two chiral centers.
True or False: Chiral molecules are always optically active.
True or False: A CH2CH2Br is higher priority than a CH2F.
True or False: Meso molecules with two stereocenters have a R,S configuration.
True or False: Diastereomers have the same physical properties except in a chiral environment.
True or False: Compound H has an optical activity of 0.
True or False: A C=C double bond is higher priority than a -CH(CH3)2.
Answer:
See explanation
Explanation:
-) True or False: All R stereocenters are dextrorotatory.
The absolute configuration is based is in specific rules that are not related to the ability to deflect polarized light. FALSE
-) True or False: Chiral centers in organic molecules will have 4 different groups attached to a carbon.
A chiral carbon by definition is a carbon with 4 groups. TRUE
-) True or False: A racemic mixture has an optical activity of 0.
In a racemic mixture, we have equal amounts of enantiomers, and this cancels out the optical activity. TRUE
-) True or False: Normal linear amines can be chiral centers.
In primary amines, we have 2 hydrogens. Therefore all the groups can not be different. So, is TRUE
-)True or False: Compound C has an optical activity of 0.
We need to know the structure of the compound
-)True or False: If the R isomer of a molecule has an optical rotation of + 25.7 degree then the S isomer of the molecule will have an optical rotation of -25.7 degree.
If we have the exact opposite (as we have in this case) the magnitud of the optical activity value will remain and the sign will change. TRUE
-)True or False: A CN is a higher priority than a CH2OH.
In this case, a carbon is directly bonded to the chiral carbon. The carbon on CN is bonded to a nitrogen atom and the carbon on CH2OH is bonded to an oxygen. So, the CH2OH will have more priority because O has a higher atomic number. FALSE
-)True or False: All molecules with chiral centers are optically active.
We can have for example mesocompounds in which the optical activity is canceled out due to symmetry planes. FALSE
-)True or False: To have an enantiomer a molecule must have at least two chiral centers.
A pair of enantiomers is made between at least 1 chiral carbon. Enantiomer R and enantiomer S. FALSE
-)True or False: Chiral molecules are always optically active.
We can have racemic mixtures or mesocompounds with chiral carbons but without optical activity. FALSE
-)True or False: A CH2CH2Br is higher priority than a CH2F.
The "Br" atom is bonded in the third carbon (respect to the chiral carbon) and the "F" atom is bonded to the second carbon. Therefore CH2F has more priority than CH2CH2Br. FALSE
-)True or False: Meso molecules with two stereocenters have a R,S configuration.
On the compounds with R and S configuration at the same time can have symmetry planes so, we will not have optical activity. TRUE
True or False: Diastereomers have the same physical properties except in a chiral environment.
All diastereomers have the same physical properties. TRUE
True or False: Compound H has an optical activity of 0.
We have to have the structure of the compound.
True or False: A C=C double bond is higher priority than a -CH(CH3)2.
In the case of C=C, we can say that is equivalent to two carbon bonds without hydrogens. Therefore C=C has higher priority. TRUE
A sample of drinking water contains 668 ppm of lead. How many grams of lead are there in 100.0 g of this water?
Answer:
0.0668g
Explanation:
Step 1: Given data
Concentration of lead: 668 ppm (mg/kg)
Mass of water: 100.0 g
Step 2: Convert the mass of water to kilograms
We will use the relationship 1 kg = 1,000 g.
[tex]100.0g \times \frac{1kg}{1,000g} = 0.1000kg[/tex]
Step 3: Calculate the mass of lead in 0.1000 kg of water
There are 668 mg of Pb in 1 kg of water.
[tex]0.1000kgWater \times \frac{668mgPb}{1kgWater} = 66.8mgPb[/tex]
Step 4: Convert the mass of Pb to grams
We will use the relationship 1 g = 1,000 mg.
[tex]66.8mg \times \frac{1g}{1,000mg} = 0.0668g[/tex]
Why are antiparallel beta sheets more stable than parallel beta sheets?
Answer:
The side chains of the amino acids alternate above and below the sheet
Explanation:
Hydrogen bonds are formed between the amine and carbonyl groups across strands. ... Antiparallel ß sheets are slightly more stable than parallel ß sheets because the hydrogen bonding pattern is more optimal.
One of the nuclides in spent nuclear fuel is U-235, an alpha emitter with a half-life of 703 million years. How long will it take for an amount of U-235 to reach 24.0% of its initial amount? Express your answer in years to three significant figures. View Available Hint(s)
Answer:
1447584654 years or 1.44 billion years
Explanation:
From the formula;
0.693/t1/2=2.303/t log No/N
Where;
t1/2 = half life of the U-235 nuclides
No= amount of U-235 initially present
N= amount of U-235 present after a time t
t= time taken for N amount of U-235 to remain
Since N= 0.24No
Substituting values
0.693/703×10^6 = 2.303/t log No/0.24No
9.8578×10^-10 = 2.303/t log 1/0.24
9.8578×10^-10 = 1.427/t
t= 1.427/9.8578×10^-10
t= 1447584654 years
A certain radioactive nuclide has a half life of 1.00 hour(s). Calculate the rate constant for this nuclide. s-1 Calculate the decay rate for 1.000 mole of this nuclide. decays s-1
Answer:
k= 1.925×10^-4 s^-1
1.2 ×10^20 atoms/s
Explanation:
From the information provided;
t1/2=Half life= 1.00 hour or 3600 seconds
Then;
t1/2= 0.693/k
Where k= rate constant
k= 0.693/t1/2 = 0.693/3600
k= 1.925×10^-4 s^-1
Since 1 mole of the nuclide contains 6.02×10^23 atoms
Rate of decay= rate constant × number of atoms
Rate of decay = 1.925×10^-4 s^-1 ×6.02×10^23 atoms
Rate of decay= 1.2 ×10^20 atoms/s
Calculate the standard enthalpy change for the reaction at 25 ∘ C. Standard enthalpy of formation values can be found in this list of thermodynamic properties.HCl(g)+NaOH(s)⟶NaCl(s)+H2O(l)
Answer:
-179.06 kJ
Explanation:
Let's consider the following balanced reaction.
HCl(g) + NaOH(s) ⟶ NaCl(s) + H₂O(l)
We can calculate the standard enthalpy change for the reaction (ΔH°r) using the following expression.
ΔH°r = 1 mol × ΔH°f(NaCl(s)) + 1 mol × ΔH°f(H₂O(l)) - 1 mol × ΔH°f(HCl(g)) - 1 mol × ΔH°f(NaOH(s))
ΔH°r = 1 mol × (-411.15 kJ/mol) + 1 mol × (-285.83 kJ/mol) - 1 mol × (-92.31 kJ/mol) - 1 mol × (-425.61 kJ/mol)
ΔH°r = -179.06 kJ
Twenty-five milliliters of 0.10 M HCl is titrated with 0.10 M NaOH. What is the pH after 15 ml of NaOH has been added
Answer:
The correct answer is 1.60.
Explanation:
Based on the given question, 25 ml of 0.10 M HCl is titrated with 0.10 M NaOH. Now moles of HCl can be determined by using the formula,
Moles = volume * concentration of HCl
= 25/1000*0.10 = 0.0025 moles
Similarly the moles of NaOH added will be determined by using the formula,
Moles of NaOH added = volume * concentration of NaOH
= 15/1000 * 0.10 = 0.0015 moles
The reaction taking place in the given case is,
HCl + NaOH = NaCl + H2O
Now the moles of excess H+ = moles of excess HCl
= 0.0025 - 0.0015 = 0.001 moles
Based on the given question, the sum of the volume of the solution is 25+15 = 40 ml or 0.040 L
[H+] = moles of H+/total volume
= 0.001 / 0.040 = 0.025 M
pH = -log[H+]
= -log[0.025]
= 1.60
The pH after 15 ml of NaOH has been volume is 1.60.
Calculation of Concentration of HCl Moles
It is based on the given question that is, 25 ml of 0.10 M HCl is titrated with 0.10 M NaOH. Now moles of HCl can be specified by using the formula,
Moles is = volume * concentration of HCl
Then is = 25/1000*0.10 = 0.0025 moles
Besides, the moles of NaOH added will be determined by using the formula,
When the Moles of NaOH added is = volume * concentration of NaOH
= 15/1000 * 0.10 = 0.0015 moles
When The reaction taking place in the given case is,
HCl + NaOH = NaCl + H2O
Now the moles of excess H+ = moles of excess HCl
= 0.0025 - 0.0015 = 0.001 moles
Then It Based on the given question, the sum of the volume of the solution is 25+15 = 40 ml or 0.040 L
[H+] = moles of H+/total volume
After that = 0.001 / 0.040 = 0.025 M
pH = -log[H+]
Then = -log[0.025]
Therefore, = 1.60
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Draw the structural formula of the principal organic product formed when ethyl benzoate is treated with C6H5MgBr (two equivalents), then HCl/H2O.
Answer:
Ph3OH
Explanation:
The reaction is between ethyl benzoate (PhCOOC2H5) and a Grignard reagent PhMgBr(C6H5MgBr).
The first step in the reaction mechanism is that the ethyl benzoate is converted to PhCOPh by the first molecule of Grignard reagent.
The second molecule of Grignard reagent now converts PhCOPh to Ph3O^-. In the presence of acid, Ph3O^- is now protonated to yield Ph3OH which is the major organic product of the reaction.
See image attached for more details.
Balance the following skeleton reaction and identify the oxidizing and reducing agents: Include the states of all reactants and products in your balanced equation. You do not need to include the states with the identities of the oxidizing and reducing agents.
CrO_4^2- (aq) + N_2O(g) rightarrow Cr^3+ (aq) + NO(g) [acidic]
The oxidizing agent is:_______.
The reducing agent is:_______.
Answer:
Oxidizing agent - CrO4^2-
Reducing agent- N2O
Explanation:
Let us look at the equation closely;
CrO4^2- (aq) + 3N2O(g) ------------> Cr^3+ (aq) + 3NO(g) [acidic]
The reduction half equation is;
CrO4^2- (aq) + 3e -------->Cr^3+ (aq)
Oxidation half equation is;
3N2O(g) ------>3 NO(g) +3 e
Note that the oxidizing agent participates in the reduction half equation while the reducing agent participates in the oxidation half equation as seen above.
One kilogram of butane (C4H10) is burned with 25 kg of air that is at 308C and 90 kPa. Assuming that the combustion is complete and the pressure of the products is 90 kPa, determine (a) the percentage of theoretical air used and (b) the dew-point temperature of the products.
Explanation:
Combustion of butane gives following reaction
C4H10 + 13/2 O2 → 5H20 + 4CO2
Therefore, One Kg of Butane consists of 1000/58 moles . That is 17.24 moles.
17.24 moles of butane reacts with (6.5×17.24) moles of O2 = 112.06 moles = 3.586 Kg O2.
Weight % of O2 in Air = 20 %
Mass of theoretical air used is 3.586×5 = 17.93 Kg = 71.72 %
The dew point temperature of H2O is :
D = (237.3×B)/(1-B)
B = ln(E/6.108)/17.27
E is vapor pressure at given temp.
At T = 30° C , E = 31.8 mm of Hg = 41.84 Milli Bars
B = 0.1114
D = 29.74°C
Danial has a simple of pure copper.its mass 89.6 grams (g),and its volume is 10 cubic centermeters (cm3) whats the destiny of the sample?
Answer:
8.96g\ cm3
Explanation:
D = ( 89.6g \ 10cm3)
( 89.6\ 10) ( g\ cm3) = 8.96g\cm3
what is the name of this molecule?
Calculate the amount of heat energy, in kJ, needed to increase the temperature of 200g of water by 300 C.
Answer:
Q = 246 kJ
Explanation:
It is given that,
Mass of water, m = 200 g
Let initial temperature, [tex]T_i=5^{\circ}[/tex]
Final temperature of water, [tex]T_f=300^{\circ} C[/tex]
We know that the specific heat capacity of water, [tex]c=4.18\ J/g-^{\circ} C[/tex]
So, the heat energy needed to raise the temperature is given by :
[tex]Q=mc\Delta T\\\\Q=200\times 4.18\times (300-5)\\\\Q=246620\ J[/tex]
or
Q = 246 kJ
So, the heat energy of 246 kJ is needed.
A spinning turbine can generate electricity only in the form of a/an _______ current.
Of all the alternative energy technologies presented in this section, only solar panels produce a/an _______ current.
Answer:
The correct answer is - alternating and direct, in order.
Explanation:
Alternating current is is type of electric current that is characterized by the direction of the flow of electrons in continuously switches its directs in opposite manner at regular cycles. While direct current or DC is flow of the electrons that move from starting to end in one direction.
Spinning turbines always leads to the alternating electric current while only solar energy produces the direct current with the help of the solar panels.
Thus, the correct answer is - alternating and direct, in order.
Answer:
1. alternating
2. direct
3. The sun heats up the atmosphere as Earth spins, creating areas of high and low temperature. This temperature difference causes wind to start moving through convection, which can then drive a wind turbine to produce electricity.
Explanation:
From Penn
How does a balanced chemical equation show the conservation of mass?
A. It shows that the number of each type of atom stays the same.
B. It shows that the mass of the products is greater than the mass of
the reactants when a reaction increases the moles of substances.
C. It shows that the total number of moles of substances stays the
same.
D. It shows that the mass of the reactants is greater than the mass
Answer:
A. It shows that the number of each type of atom stays the same.
Explanation:
Though you may see a change in the way they are arranged, the same number of atoms are present before and after. Balanced chemical equations show equal numbers of atoms of each element on each side of the equation.
Which, if any, of the two molecular geometries is likely to be polar if the outer atoms are identical and there is a difference in electronegativity between the central atom and the outer atoms
Answer:
Polar molecules are not symmetrical
Explanation:
Even though the structures of the molecules involved were not shown in the question, but I will proceed to give a general explanation of the conditions that describe a polar molecule.
First of all, symmetrical molecules are non-polar and asymmetrical molecules are polar. This is the reason why CF4 will be a nonpolar molecule but H2O will be a polar molecule. Some symmetrical molecules may may posses polar bonds or dipoles but these dipoles eventually cancel out since the molecule is symmetrical in nature.
Summarily, if a molecule possess the same type of atoms attached to the central atom with some symmetry axes, like C3, C4 etc., we will end up with a non polar molecule but if we have a nonplanar molecule, then we will end up finding it to be polar.
A chemistry student weighs out of lactic 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
Answer:
28.0mL of the 0.0500M NaOH solution
Explanation:
0.126g of lactic acid diluted to 250mL. Titrated with 0.0500M NaOH solution.
The reaction of lactic acid, H₃C-CH(OH)-COOH (Molar mass: 90.08g/mol) with NaOH is:
H₃C-CH(OH)-COOH + NaOH → H₃C-CH(OH)-COO⁻ + Na⁺ + H₂O
Where 1 mole of the acid reacts per mole of the base.
You must know the student will reach equivalence point when moles of lactic acid = moles NaOH.
the student will titrate the 0.126g of H₃C-CH(OH)-COOH. In moles (Using molar mass) are:
0.126g ₓ (1mol / 90.08g) = 1.40x10⁻³ moles of H₃C-CH(OH)-COOH
To reach equivalence point, the student must add 1.40x10⁻³ moles of NaOH. These moles comes from:
1.40x10⁻³ moles of NaOH ₓ (1L / 0.0500moles NaOH) = 0.0280L of the 0.0500M NaOH =
28.0mL of the 0.0500M NaOH solutionWhat is the empirical formula for the compound: C8H8S2?
Answer:
Empirical formula = C4H4SExplanation:
The subscripts in a formula determine the ratio of the moles of each element in the compound. To convert this formula to the empirical formula, divide each subscript by 2. This is similar to reducing a fraction to its lowest denominator.
An energy of 13.6 eV is needed to ionize an electron from the ground state of a hydrogen atom. Selecting the longest wavelength that will work from the those given below, what wavelength is needed if a photon accomplishes this task
Answer:
The wavelength is [tex]\lambda = 91nm[/tex]
Explanation:
From the question we are told that
The energy required is [tex]E = 13.6 \ eV[/tex]
This energy needed in form of a photon can be mathematically represented as
[tex]E = \frac{h * c }{\lambda }[/tex]
where h is the Planck constant with a value [tex]h = 4.1357 * 10{-15} eV \cdot sec[/tex]
and c is the speed of light which is
substituting values
[tex]13.6 eV = \frac{ 4.1357 * 10^{-15} eV * 3.0*10^8 }{\lambda }[/tex]
= > [tex]\lambda = 9.1*10^{-8}[/tex]
[tex]\lambda = 91nm[/tex]
AB2AB2 has a molar solubility of 3.72×10−4 M3.72×10−4 M. What is the value of the solubility product constant for AB2AB2? Express your answer numerically.
Answer:
Ksp = 2.06x10⁻¹⁰
Explanation:
For AB₂. solubility product constant, Ksp, is written as follows:
AB₂(s) ⇄ A²⁺ + 2Br⁻
Ksp = [A²⁺] [Br⁻]²
Molar solubility represents how many moles of AB₂ are soluble per liter of solution. and is obtained from Ksp:
AB₂(s) ⇄ A²⁺ + 2Br⁻
AB₂(s) ⇄ X + 2X
where X are moles that are soluble (Molar solubility)
Ksp = [X] [2X]²
Ksp = 4X³As molar solubility of the salt is 3.72x10⁻⁴M:
Ksp = 4X³
Ksp = 4(3.72x10⁻⁴)³
Ksp = 2.06x10⁻¹⁰Question 4
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A solution is prepared at 25°C that is initially 0.42 M in an "X" base, a weak base with Kb=7.4X10^-4, and 0.42 M in conjugate acid "HX". Calculate the pH of the
solution. Round your answer to 2 decimal places.
(Hint: pkw=pka + pkb)
A Moving to another question will save this response.
< Question 4 of 12>
Answer:
pH = 10.87
Explanation:
You can find pH of a buffer (Mixture of a weak base, X, and its conjugate acid, HX) by using H-H equation:
pH = pKa + log [X] / [HX]
pKb is -log Kb = 3.13
Using Hint pKw = pKa + pKb (pKw = 14)
pKw = pKa + pKb
14 - 3.13 = pKa
10.87 = pKa
Replacing in H-H equation:
pH = 10.87 + log [0.42M] / [0.42]
pH = 10.87 + log 1
pH = 10.87A solution containing lead(II) nitrate is mixed with one containing sodium bromide to form a solution that is 0.0630 M in Pb(NO3)2 and 0.0103 M in NaBr. What is the value of Q for the insoluble product? Express the reaction quotient to three significant figures.
Answer:
Q = 6.68x10⁻⁶
Explanation:
The initial solutions are Pb(NO₃)₂ and NaBr. As sodium and nitrates salts are soluble, the insoluble product must be the formed from the other ions, PbBr₂.
The soluble product equilibrium is written as:
PbBr₂(s) ⇄ Pb²⁺(aq) + 2Br⁻(aq)
Where Q is defined as:
Q = [Pb²⁺] [Br⁻]²
As:
[Pb²⁺] = 0.0630M
[Br⁻] = 0.0103M
Q = [Pb²⁺] [Br⁻]²
Q = [0.0630M] [0.0103M]²
Q = 6.68x10⁻⁶