Answer:
9-fluorenone binds more strongly to the stationary phase.
Explanation:
9-fluorenone is more polar than fluorene because it possesses a carbonyl group. Recall that the stationary phase is alumina and alumina is a polar adsorbent. Alumina is a top choice for the separation of components that contain a weakly or moderately polar component. These polar components of the mixture are retained for a longer time and more selectively by the adsorbent.
The fluorene is eluted first with the Petroleum ether, this makes it easier to elute the 9-fluorenone with the dichloromethane. The 9-fluorenone will be slower because it is more strongly attracted to the alumina owing to its polar carbonyl group.
Fluorene moves faster because its' polarity is the same as Petroleum ether and also opposite of the alumina. If the order of solvents is reversed and dichloromethane is first used, the 9-fluorenone binds more strongly to the alumnina making it difficult to elute fluorene using Petroleum ether.
A compound has a molar mass of 100 g/mol and the percent composition (by mass) of 65.45% C, 5.45% H, and 29.09% O. Determine the empirical formula and the molecular formula.
Answer:
Empirical formula: C3H30
Molecular formula: C6H6O2
Explanation:
The empirical formula can be calculated thus:
65.45% C - 65.45g
5.45% H - 5.45g
29.09% O - 29.09g
We convert each mass to mole by dividing by their respective atomic mass:
C = 65.45/12 = 5.45mol
H = 5.45/1 = 5.45mol
O =29.09/16 = 1.82mol
Next, we divide each mole value by the smallest value;
C = 5.45mol/1.82 = 2.99
H = 5.45mol/1.82 = 2.99
O = 1.82mol/1.82 = 1
Approximately, the empirical ratio of C, H and O is 3:3:1 i.e. C3H3O
Molecular formula is calculated thus:
(C3H3O)n = 100g/mol
{12(3) + 1(3) + 16}n = 100
(36+3+16)n = 100
(55)n = 100
n = 100/55
n = 1.82
n = 2
Molecular formula= (C3H3O)2
C6H6O2
Why does the 4s sublevel fill up before the 3d sublevel? What principle is that based on?
According to the Aufbau principle, the 4s orbital is filled first instead of the 3d orbital
Further explanationEach electron shell and its orbitals have a specific energy level.
The farther the shell is from the atomic nucleus, the higher the energy level.
This energy level is expressed in the form of electron configurations.
Writing electron configurations starts from the lowest to the highest sub-shell energy level. There are 4 sub shell in the shell of an atom, namely s, p, d and f.
Charging electrons in the subshell uses the following sequence:
1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁶, 5s², 4d¹⁰, 5p⁶, 6s², etc.
According to Aufbau, electrons occupy orbitals of the lowest energy level
So the 4s orbital has a lower energy level than the 3d orbital, so the electrons fill the 4s orbital first
If the molar absorptivities of HIn and In- were determined at a wavelength corresponding to an isosbestic point, how would they compare in value
Answer:
A Weak acid indicator has general formulae HIn- and base has In-.
When constructed a plot determining wavelength equilibrium reached according to the equation HIn(aq) + H2O(l) ↔ In-(aq) + H3O+(aq)
HIn(aq) is the acid, that has a different color from the base In-(aq). When the pH is low, the concentration of the hydronium ion H3O+ is high and equilibrium is toward the left, producing the color A.
At high pH, the concentration of H3O+ is low, so equilibrium tends toward the right side of the equation and color B is displayed
Which of the following is not present in an atom? (1 point) Electron Element Neutron Proton
Answer:
Element is not present in an atom
Answer:
element
Explanation:
What is the equilibrium expression for the following reaction: N2 (g) 3 H2 (g) rightwards harpoon over leftwards harpoon with blank on top 2 NH3 (g)
Answer:
[tex]Kp = \frac{P_{NH_{3}} ^{2} }{P_{N_{2}} ^{}P_{H_{2}} ^{3} }[/tex]
Explanation:
For the reaction at equilibrium:
N₂ (g) + 3 H₂(g) ⇄ 2 NH₃ (g)
Since this is an equilibrium in the gas phase, the equilibrium expression is obtained from the partial pressures (P) of the products (NH₃) and reactants (N₂ and H₂) raisen to their stoichiometric coefficients:
[tex]Kp = \frac{P_{NH_{3}} ^{2} }{P_{N_{2}} ^{}P_{H_{2}} ^{3} }[/tex]
1. In the tests with NaI/acetone and AgNO3/ethanol, as described in the experiment, it was found that benzyl chloride (PhCH2Cl) reacts in both tests. Why is this compound able to react under both conditions
Answer:
See explanation
Explanation:
Let us remember that the Iodide ion is a good nucleophile. SN2 reaction is promoted in a polar aprotic solvents like acetone.
Aprotic solvents like acetone do not favor the formation of a carbocation hence the reaction of Sodium iodide in acetone with PhCH2Cl proceeds by SN2 mechanism. This is possible because the compound possesses a halogen atom(Cl) which is easily replaced by I^- from NaI. The corresponding NaCl formed is insoluble in acetone.
Similarly, when AgNO3/ethanol reacts with PhCH2Cl; ethanol which is a polar protic solvent and a poor nucleophile coordinates with the silver ion in the PhCH2Cl and enhances carbocation formation (SN1 mechanism operates).
The SN2 mechanism is not followed here because there is no good nucleophile present compared to the situation in the reaction of PhCH2Cl with NaI/acetone.
State yes no whether each of the following orbital diagrams conforms to the rules governing electron configuration if not explain what is wrong with the diagram
Answer:yes,no,no,yes
please help!! chemistry question
Answer:
9
Explanation:
Answer:
9
because i studied this
I have 5.33 moles of helium gas at 1.56 atm and a temperature of 25 ° C. What is the volume of my helium sample? 
Answer:
V = 83.6 L
Explanation:
Given data:
Number of moles of He = 5.33 mol
Pressure of gas = 1.56 atm
Temperature of gas = 25°C
Volume of sample = ?
Solution:
Formula:
PV = nRT
P= Pressure
V = volume
n = number of moles
R = general gas constant = 0.0821 atm.L/ mol.K
T = temperature in kelvin
Now we will convert the temperature.
25+273 = 298 K
Now we will put the values in formula.
1.56 atm × V = 5.33 mol × 0.0821 atm.L/ mol.K × 298 K
1.56 atm × V = 130.4 atm.L
V = 130.4 atm.L/1.56 atm
V = 83.6 L
How do I know if something is an acid so I can avoid eating it?
Answer:
i feel like it will have an acid smell
What happens to gas molecules if you take away heat?
Answer:
Taking energy away from a gas cooling it down may cause it to turn into a liquid or condense
Answer:
sold,liquidator gas
Explanation:
pressure| practicelmodel of matter| siyavula
Based on these descriptions, write a balanced equation and the corresponding Kc expression for each reversible reaction.
a. Carbonyl fluoride, COF2(g), decomposes into gaseous carbon dioxide and gaseous carbon tetrafluoride.
b. Copper metal displaces Silver(I) Ion from aqueous solution , producing silver metal and an aqueous solution of copper(II) ion.
c. Peroxodisulfate ion , S2O82- , oxides iron (II) ion to iron (III) ion in aqueous solution and it is itself reduced to sulfate ion.
Answer:
See full explanation.
Explanation:
Hello.
In this case, since we apply the law of mass action in order to write the equilibrium expression for each chemical reaction, we proceed as follows:
a. The reaction is:
[tex]2COF_2(g)\rightleftharpoons CO_2(g)+CF_4(g)[/tex]
And the equilibrium expression:
[tex]Kc=\frac{[CO_2][CF_4]}{[COF_2]^2}[/tex]
Since all the species are in gaseous phase they are included on the equilibrium expression.
b. The reaction is:
[tex]Cu(s)+Ag^+(aq)\rightleftharpoons Ag(s)+Cu^{2+}(aq)[/tex]
And the equilibrium expression:
[tex]Kc=\frac{Cu^{2+}}{Ag^+}[/tex]
Since only copper (II) ions and silver (I) ions are in aqueous phase.
c. The reaction is redox and it turns out:
[tex](S_2O_8)^{2-}+Fe^{2+}\rightleftharpoons Fe^{3+}+(SO_4)^{2-}\\\\S_2^{7+}+2e^-\rightarrow 2S^{6+}\\\\2\times (Fe^{2+}\rightarrow Fe^{3+}+1e^-)\\\\\\(S_2O_8)^{2-}(aq)+2Fe^{2+}(aq)\rightleftharpoons 2Fe^{3+}(aq)+2(SO_4)^{2-}(aq)[/tex]
And the equilibrium expression:
[tex]Kc=\frac{[Fe^{3+}]^2[(SO_4)^{2-}]^2}{[(S_2O_8)^{2-}][Fe^{2+}]^2}[/tex]
Since all the species are in aqueous phase.
Calculate the concentration of 45.0 mL of a phosphoric acid solution that neutralized 20.8 mL of 0.532 M sodium hydroxide. Assume complete ionization of the acid.
Answer:
0.0820M H₃PO₄
Explanation:
THe phosphoric acid, H₃PO₄ reacts with sodium hydroxide, NaOH, thus:
H₃PO₄ + 3NaOH → Na₃PO₄ + 3H₂O
The moles of NaOH used to neutralize the acid are:
Moles NaOH:
20.8mL = 0.0208L * (0.532mol / L) = 0.0111 moles NaOH.
That means moles of phosphoric acid in the solutionare:
0.0111 moles NaOH * (1mole H₃PO₄ / 3 moles NaOH) =
0.00369 moles H₃PO₄
These moles are in 45.0mL = 0.045L. The molar concentration of the solution are:
0.00369 moles H₃PO₄ / 0.045L =
0.0820M H₃PO₄4) How many moles are in each elemental sample?
a. 9.01 g Be
b. 42.03 g P
c. 71.90 g CI
Answer:
1 mole
The first step is to calculate the molar mass (gram formula weight) of MgCl2. Molar mass = (24.31 + 2 × 35.45) = 95.21 g mol–1 i.e. 95.21 g of MgCl2 is exactly 1 mole
Can someone answer #1 for me please I’ll gift extra points! ☺️
GREETINGS!
The system here is chloroplast, so the boundary of the system would be cell cell membrane. Input will be nutrients, output waste and process photosynthesis
HOPE IT HELPS!
A 1.90-g sample of an oxide of bromine is converted to 3.188 g of AgBr. Calculate the empirical formula of the oxide. (molar mass for AgBr =187.78 g/mol)
a. BrO
b. Br2O
c. BrO
d. BrO3
e. None of these
Answer:
e. None of these
Explanation:
The oxide of Bromine (BrₐOₓ) produce "a" moles of Br that are equal to "a" moles of AgBr. The moles of AgBr are:
Moles AgBr:
3.188g AgBr * (1mol / 187.78g) = 0.01698 moles of AgBr = Moles of Br
These moles of Br weighs (Molar mass: 79.9g/mol):
0.01698 moles of Br * (79.9g / mol) = 1.36g of Br
Mass of Oxygen must be:
1.90g - 1.36g Br = 0.54g oxygen. In moles:
0.54g O * (1mol / 16g) = 0.03375 moles of O
Empirical formula is the simplest ratio of atoms in the molecule. Dividing in the moles of Br:
Br: 0.01698 moles of Br / 0.01698 moles = 1
O: 0.03375 moles of O / 0.01698 moles = 1.99 ≅ 2
That means empirical formula is:
BrO₂
And right option is:
e. None of theseThe empirical formula of the oxide would be [tex]BrO_2[/tex]
1.90 g of the oxide of bromine produces 3.188 g of AgBr
moles of 3.188 g AgBr = 3.188/187.78
= 0.017 moles
AgBr ---> Ag+ + Br-
Thus, mole of Br in AgBr = 0.017 moles
Mass of 0.017 Br = mole x molar mass
= 0.017 x 79.904
= 1.357 g
Mass of oxygen in the oxide of bromine = 1.90 - 1.357
= 0.543 g
mole of 0.543 oxygen = 0.543/16
= 0.0339 moles
mole of 1.357 g Br = 0.017
Dividing by the smallest:
Br = 0.017/0.017 = 1
O = 0.0339/0.017 = 1.99
Empirical formula = BrO2
More on empirical formula can be found here: https://brainly.com/question/1247523?referrer=searchResults
The rate constant for a certain reaction is measured at two different temperatures:
Temperature K
376.0°C 4.8 x 10^8
280°C 2.3 x 10^8
Assuming the rate constant obeys the Arrhenius equation, calculate the activation energy for this reaction. Round your answer to significant digits.
Answer: 22.78KJ/ mol
Explanation:
The computation of activation energy [tex]E_0[/tex] follows by formula:
[tex]\ln (\dfrac{K_2}{K_1}) = (\dfrac{E_a }{ R}) (\dfrac{1}{T_1} -\dfrac{ 1}{T_2})[/tex]
Given:[tex]T_1 = 376.0^{\circ}C =376+273K= 649 K[/tex]
[tex]K_1 = 4.8 \times10^8[/tex]
[tex]T_2 = 280.0^{\circ}C = 273+280K=553 K ,\ \ \ K_2 = 2.3 \times 10^8[/tex]
[tex]\ln(\dfrac{2.3 \times10^8 }{ 4.8 \times 10^8}) = (\dfrac{E_a }{ 8.314}) (\dfrac{1}{649} - \dfrac{1}{553})\\\\\Rightarrow\ \ln(0.479) = (\dfrac{E_a }{ 8.314}) (-\dfrac{96}{358897})\\\\\Rightarrow\ -0.73605468= (\dfrac{E_a }{ 8.314}) (-\dfrac{96}{358897})\\\\\Rightarrow\E_a=-0.73605468\times 8.314\times\dfrac{-358897}{96}=22878.033\\\\\Rightarrow\E_a=22878.033\ J/mol=22.78 KJ /mol[/tex]
Hence, the activation energy for this reaction =22.78KJ/ mol
Calcium oxide reacts with water in a combination reaction to produce calcium hydroxide. A 4.50-g sample of CaO is reacted with 4.34 g of H2O. How many grams of the excess reagent remain after the reaction is complete
Answer:
2.88 g
Explanation:
First, let us look at the balanced equation of the reaction:
[tex]CaO(s) + H_2O (l) --> Ca(OH)_2(s)[/tex]
From the equation, 1 mole of CaO reacts with 1 mole of H2O to produce 1 mole of [tex]Ca(OH)_2[/tex].
mole = mass/molar mass
4.50 g of CaO = 4.50/56.08 = 0.08 mole
4.34 g of H2O = 4.34/18.02 = 0.24 mole
The ratio of moles of CaO and H2O should be 1:1, hence, H2O is in excess.
Excess mole of H2O = 0.24 - 0.08 = 0.16 mole
mass of 0.16 mole of H2O = mole x molar mass = 0.16 x 18.02 = 2.88 g
Therefore, 2.88 g of the excess reagent (water) would remain after the reaction is complete.
a half-eaten apple turns brown which of these is evidence a chemical change took place
A.th3e apple is softer
b.the apple changed color
C.half the apple was eaten
D.the apple is warmer \
Answer:
the apple changed color
Explanation:
cause when it changes to brown it means the apple is no longer edible
many fruits with just having contact with the air it may change color like apple
Choose the reaction that represents the combustion of liquid C6H14?
a. C6H12O2(l) + 8 O2(g) → 6 C(s) + 6 H2O(g)
b. 6 C(s) + 7O2(g) + C6H14(l) → C6H14O2(aq) + 6CO2(g)
c. 6 C(s) + 6 H2(g) + 19 O2(g) → C6H14(l)
d. 2C6H14(l) + 19 O2(g) → 12 CO2(g) + 14 H2O(g)
HELP!!!!
Answer:
D. It's the only one with C6H14 on the reactant side.
Explanation:
For ethane (C2H6), what is the correct framework of the Lewis structure?
The central atoms consist of two hydrogens.
The central atoms consist of two hydrogens and one carbon.
The central atoms consist of one hydrogen and one carbon.
The central atoms consist of two carbons.
Answer: The answer is D. The central atoms consist of two carbons.
Explanation:
Answer:
The central atoms consist of two carbons
Explanation:
Took the test! hope this helps!
Silicon has three naturally occurring isotopes. Based on the AVERAGE atomic mass, which is 28.085, what is the likely mass of the most common isotope? *
Answer: This means that the isotope of silicon with a mass number of 28 is by far the most common of these three isotopes.
Explanation:
The abundance of Si-28 is 92.23%. Si-29 is 4.68% and Si-30 is 3.09%.
which 2 letters have the most kinetic energy
Answer:
X and Z
Explanation:
See attachment for complete question...
Your question illustrates kinetic energy as it relates to height (according to the attachment)
Kinetic energy increases with a decrease in height.
So, from the attachment...
W and Y are at higher heights.
While X and Z are at lowest heights
By the analysis above, kinetic energy would be at highest at X and then Z.
Hence, the answer to the question is X and Z.
How many Joules are required to change 30.0g ofice at -20°C to steam at 140°C? There are a few steps you should follow using the following given
information
• The specific heat of ice is 2.108 J/g*°C
• The specific heat of water is 4.18 J/g*°C
• The specific heat of steam is 2.010 J/g*°C
• Hf for H2O = 334 334 J/g
• Hv for H2O = 2260 J/g
Answer:
Q = 10118.4 j
Explanation:
Given data:
Mass of ice = 30.0 g
Initial temperature of ice = -20°C
Final temperature = 140°C
Energy required = ?
Solution:
The specific heat of ice is 2.108 J/g*°C
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
ΔT = 140°C - (-20°C)
ΔT = 160°C
Q = 30.0 g× 2.108 J/g°C ×160°C
Q = 10118.4 j
how do you find an unknown element
Answer:
There are two properties that can be used to identify an element: the atomic number or the number of protons in an atom. The number of neutrons and number of electrons are frequently equal to the number of protons, but can vary depending on the atom in question.
- On a test, Helena is defining energy. Which must she include in order to get her answer marked correct?
○making objects more compact
O the ability to do work
O carrying through matter and space
O the bonds of atoms
Answer: Option 2, The ability to do work.
Explanation: Edge
Energy can be defined as:
B. the ability to do work, It can of many forms.
What is Energy?Energy is the capacity of an item to take care of business. It might exist in potential, motor, warm, electrical, substance, atomic, or other different structures. As per the work-energy hypothesis, the work done is put away in the energy of the body.
Thus, option B is correct.
Find more information about Energy here:
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Hydrazine reacts with 2,4-pentanedione to yield 3,5-dimethylpyrazole. Including protonations and deprotonations, the reaction takes 12 steps. Write out the mechanism on a sheet of paper and then draw the structure of the product of step 9.
Answer:
Explanation:
From the given information:
We explained the reaction mechanism of 2,4-pentanedione with hydrazine to yield 3,5-dimethylpyrazole as shown below;
At the initial stage, the carbonyl oxygen gains a proton, increasing the carbonyl carbon's electrophilicity. After that, the carbonyl carbon is being attacked by hydrazine. Then, the process proceeds with the species formed where removal of a proton takes place. Similarly, hydroxyl oxygen gains a proton. After that, the water molecule is being removed, and further rearrangement of an electron occurs at the site of nitrogen in hydrazine.
From species formed, the removal of a proton takes place. Finally, all step is being repeated to yield the final product known as 3,5 - dimethylpyrazole.
g Part A A Hofmann degradation of a primary amine forms an alkene that gives butanal and 2-methylpropanal upon ozonolysis and workup under reducing conditions. Identify the amine.
Answer:
Explanation:
When the primary amine undergoes Hofmann degradation it forms an Alkene
In this case the alkenes have undergone ozonolysis and has formed two products as butanal and 2-methyl propanal
when we revert back from these aldehydes to alkene we observed the alkene formed will be "2-methyl hept-3-ene " this alkene is the Hofmann product of that primary amine
upon addition of this alkene we observe the primary amine formed is
4-amino-2-methylheptane
The atoms of which element will form cations?
A. selenium
B. neon
C. copper
D. iodine
Answer Copper, copper is a type of metal, so it can form cations
The atoms of element will form cations is Copper as to get the stable electronic configuration.
What are cations?
Cations are those species which carries possitive charge on it and produced by any element by lossing of their outermost electrons.
An atom will form cation to get the stable outermost configuration.
Selenium belongs from the oxygen group and in the outermost shell 6 electrons are present, so it shows the negative oxidation state as it accepts the two electron to get the stable configuration and form an anion.Neon belongs from the noble gas group which already have stable configuration, so it does not form any cation or anion.Iodine belongs from the halogen groups, and in the outermost shell 7 electrons are present, so it shows the negative oxidation state as it accepts the one electron to get the stable configuration and form an anion.Copper is a transition metal atom and it has 4s¹3d¹⁰ electronic configuration, so it will loss 1 electron from the outermost shell and will form cation.Hence option (C) is correct i.e. Copper.
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A student filled a graduated cylinder with water to the 15.0 mL mark she placed a metal object with a mass of 33.65g into the cylinder when the object was completely submerged in the water the water level rose to 18.3mL what is the density of the object
Answer:
The answer is 10.2 g/mLExplanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\ [/tex]
From the question
volume = final volume of water - initial volume of water
volume = 18.3 -15 = 3.3 mL
We have
[tex]density = \frac{33.65}{3.3} \\ = 10.19696969...[/tex]
We have the final answer as
10.2 g/mLHope this helps you