Answer:
C
Explanation:
Identify the possible issues if a sample in a spectrophotometer gives no reading. Select one or more: The wrong wavelength may be set. There may be an issue with the spectrophotometer. The sample may be placed impro
The question is incomplete; the complete question is;
Identify the possible issues if a sample in a spectrophotometer gives no reading. Select one or more:
The wrong wavelength may be set.
The sample may be placed improperly in the cuvette holder.
There may be an issue with the composition of the sample.
There may be an issue with the spectrophotometer
Answer:
The wrong wavelength may be set.
There may be an issue with the spectrophotometer
Explanation:
Substances do not absorb radiation at all wavelengths. The proper wavelength at which a substance absorbs must be used for a reading to be obtained from the spectrophotometer. If this is not done, no reading is obtained from the spectrophotometer.
Generally, if the spectrophotometer has an issue, it may display no reading until the machine is fixed.
The possible issues if a sample in a spectrophotometer gives no reading are:
The sample may be placed improperly in the cuvette holder. The wrong wavelength may be set.According to the given question, we are asked to identify the possible reasons why a spectrophotometer would give no reading when a sample is used on it.
As a result of this, it is important to note that it is possible that the sample may not have been placed correctly on the cuvette holder or the wrong wavelength may be set which would cause the no reading error to show.
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4) 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
help pls this is timed
Answer:
Explanation:
abything that is both mass and volume
Answer:
anything that has both mass and volume
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.
Why should you used distilled or deionized water instead of tap water when using AgNO3 as a test for anions?
Answer:
Why you use deonized water rather than tap water in this experiment? Because deonized water is pure and without contaminants that can affect the result of the experiment.
Explanation:
When using AgNO3 as the test anion, we used distilled or deionized water instead of tap water because deionized water is purer and free of contaminants that could affect the result of the experiment.
What is Distillation?Distillation is the process which involves the conversion of a liquid into water vapour and it condensed back to liquid form. It is the process in which separation of components of a mixture is based on different boiling points.
It is used to separate liquids from nonvolatile solids and also involve in the separation of alcoholic liquors from fermented materials or in the separation of two or more liquids having different boiling points, as in the separation of gasoline, kerosene, and lubricating oil from crude oil.
A plant that performs distillation is called a distillery while the apparatus used to perform distillation is called a still.
Thus, when using AgNO3 as the test anion, we used distilled or deionized water instead of tap water because deionized water is purer and free of contaminants that could affect the result of the experiment.
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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
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
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:
How many atoms are in 0.000045 grams of carbon?
Answer:
2.25E18
Explanation:
0.000045 g of Carbon x (1 mol C/ 12.01 g C) x (6.02 x 10E23 atoms / 1 mol C)
Start with the mass, then multiply it by the molar mass but put moles on the top and grams on the bottom to cancel out the grams. Then multiply it by Avogadros Constant to get atoms
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.
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
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
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.
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
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.
The concentration of H3O+ in human sweat can be as low as 2.5 × 10-6. The concentration of OH- in the sweat is ________, and this solution is ________ (acidic, basic, neutral).
Answer:
[OH⁻] = 4.0 × 10⁻⁹ M
Acidic
Explanation:
Step 1: Given data
Concentration of H₃O⁺: 2.5 × 10⁻⁶ MStep 2: Calculate the concentration of OH⁻
We will use the following expression.
[H₃O⁺].[OH⁻] = Kw = 1.0 × 10⁻¹⁴
[OH⁻] = 1.0 × 10⁻¹⁴/[H₃O⁺] = 1.0 × 10⁻¹⁴/2.5 × 10⁻⁶ = 4.0 × 10⁻⁹ M
Step 3: Calculate the pH
We will use the following expression.
pH = -log [H₃O⁺] = -log 2.5 × 10⁻⁶ = 5.6
Since the pH < 7, the solution is acidic.
Phosphorus-32 has a half life of 14 days. If we begin with 40 mg how much is left after 42 days?
Answer:
0 mg
Explanation:
after 24 days all of it would be gone.
Phosphorus only has a 24 day life span.
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 H₃PO₄A 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
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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
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:
2. Foliated rocks are characterized by
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
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%.
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.
2AgNO3The following chemical reaction takes place in aqueous solution: (aq)(aq)(s)(aq) Write the net ionic equation for this reaction.
Answer:
[tex]2Ag^+(aq)+CO_3^{2-}(aq)\rightarrow Ag_2CO_3(s)[/tex]
Explanation:
Hello.
In this case, since the reaction is not given but a typical precipitation of silver from silver nitrate could be represented by its reaction with a soluble metallic sulfide or carbonate since silver carbonate and silver sulfide are insoluble, we can use for instance sodium carbonate to obtain:
[tex]2AgNO_3(aq)+Na_2CO_3(aq)\rightarrow Ag_2CO_3(s)+2NaNO_3(aq)[/tex]
Thus, since, silver nitrate, sodium carbonate and sodium nitrate are fully ionized by silver carbonate remains solid, the complete ionic equation is:
[tex]2Ag^+(aq)+2NO_3^-(aq)+2Na^+(aq)+CO_3^{2-}(aq)\rightarrow Ag_2CO_3(s)+2Na^+(aq)+2NO_3^-(aq)[/tex]
Then, since nitrate and sodium ions are the spectator ions since they are at both reactants and products, the net ionic equation turns out:
[tex]2Ag^+(aq)+CO_3^{2-}(aq)\rightarrow Ag_2CO_3(s)[/tex]
Best regards!
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
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!
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]
