The given question is not complete, the complete question is:
A chemistry student needs 5.00 g of thiophene for an experiment. She has available 0.50 kg of a 28.7% w/w solution of thiophene in benzene, Calculate the mass of solution the student should use. If there's not enough solution, press the "No solution" button Be sure your answer has the correct number of significant digits. X
Answer:
The correct answer is 17.4 grams.
Explanation:
As mentioned in the given question, 28.7 percent w/w solution thiophene in benzene shows that,
(wt. of thiophene / wt. of thiopene + benzene) * 100 = 28.7
0.50 kg of the solution indicates that it is 500 grams of the solution.
Therefore, the amount of thiophene found in the 500 grams of the solution is,
500 g * 28.7 / 100 = 143.5 gm
Thus, 143.5 grams of thiophene is found 500 grams of the solution.
Now, 1 gram of thiophene will be in 500/143.5 of solution.
Therefore, 5 grams of thiophene will be in 500/143.5 * 5 g of the solution = 17.42 grams of the solution.
Hence, the mass of the solution to be used by the student in the given case will be 17.4 grams.
What are 3 stages of the water cycle are
The change in entropy, ΔS∘rxn , is related to the the change in the number of moles of gas molecules, Δngas . Determine the change in the moles of gas for each of the reactions and decide if the entropy increases, decreases, or has little or no change. A. 2H2(g)+O2(g) ⟶ 2H2O(l) Δngas= mol The entropy, ΔS∘rxn , increases. decreases. has little or no change.
Explanation:
Entropy of a reaction ΔS∘rxn is the degree of disoderliness in a system. Gases generally have a higher degree of disorder compared to liquids. Hence for the reaction 2H2(g)+O2(g) ⟶ 2H2O(l), the entropy decreases sice the reactants are in the gaseous state and the products is in the liquid state of matter
Which of the following 0.5 M aqueous salt solutions will have a pH of 7.0 at
LiF RbBr NaClO4 NH4Cl
A) LiF only B) NaClO4 only C) LiF and RbBr D) RbBr and NaClO4
Answer:
LiF and RbBr
Explanation:
Salt is an ionic compound that is made from the reaction of an acid and a base solution. Salts dissolve in water to give solutions that are acidic, basic, or neutral.
Salt formed from a strong acid and a weak base will make an acidic solution when added to water. The reason this occurs is because when the salt dissociates, the conjugate acid of the weak base will donate a proton, or one hydrogen ion, to water and form hydronium ion.
If a salt is formed from a weak acid and a strong base, it dissolves in water and the conjugate base of the weak acid will accept a proton from water and yield the hydroxide ion. Hence the solution of the salt will be basic.
If the salt is formed from a strong acid and a strong base, the salt is neutral when dissolved in water. Both LiF and RbBr are formed from strong acids and strong bases hence they will have a pH of 7.0 in solution.
LiF RbBr NaClO4 NH4Cl is = LiF and RbBr The correction is 'C'.
What are the Salt solutions?
Salt is an ionic mixture that is made from the reaction of an acid and a base resolution. Salts liquefy in water to give solutions that are acidic, basic, or neutral.
Salt constructed from a strong acid and a breakable base will make an acidic solution when added to water. The reason this occurs is that when the salt dissociates, the conjugate acid of the weak base will donate a proton, or one hydrogen ion, to water and form a hydronium ion.
If a grain of salt is formed from a weak acid and a powerful ground, it liquefies in water and the conjugate bottom of the weak acid will accept a proton from water and yield the hydroxide ion. Therefore, the solution of the salt will be basic.
If the salt is formed from a strong acid and a strong bottom, the salt is neutral when liquefied in water. Both LiF and also RbBr are formed from strong acids and powerful bases hence they will have a pH of 7.0 in resolution.
Therefore, the Correct option is 'C'
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A. An element with the valence electron configuration 5s1 would form a monatomic ion with a charge of ________. In order to form this ion, the element will _______ electron(s) from/into the _______ subshell(s).
B. An element with the valence electron configuration 2s22p4 would form a monatomic ion with a charge of ______. In order to form this ion, the element will ______ electron(s) from/into the _______ subshell(s)
Answer:
A) An element with the valence electron configuration 5s¹ would form a monatomic ion with a charge of +1. In order to form this ion, the element will lose electron(s) from/into the 5s subshell(s).
B) An element with the valence electron configuration 2s²2p⁴ would form a monatomic ion with a charge of +1. In order to form this ion, the element will lose electron(s) from/into the 2p (2pₓ specifically) subshell(s).
Explanation:
The secret to this task is to follow those rules for the stability of electronic structures of elements. The rules include
- Electrons are filled firstly into shells or subshells of lower energies first.
- While filling electronic structure or writing electronic structures for elements/ions, electrons are fed singly to the suborbital before pairing occurs, this is because the totally paired up electrons of a suborbital are more stable than the totally unpaired electrons of the same suborbital which is now in turn more stable than the combination of paired and unpaired electrons in the suborbitals.
A) For an element with its valence electron on 5s¹, this means that there is one valence electron on this atom's outermost shell and outermost suborbitals. So, to form a monoatomic ion, it would take between losing and gaining an electron. Gaining an electron leads to a 5s², which indicates empty 5p orbitals too and is therefore less stable than losing an electron which would lead to the loss of the shell 5 and focus on a completely filled 4-shell.
So, losing the electron from the 5s suborbital to become a monotonic ion makes it acquire a charge of +1.
B) Just like the explanation in (A), to form a monoatomic ion would require a loss or gain of an electron. With valence electrons 2s²2p⁴, gaining an electron would have led to a 2s²2p⁵ and a further breakdown as 2s²2pₓ²2pᵧ²2pz¹ which has unpaired and paired electrons in the 2p suborbital. This is evidently less stable than if an electron was lost, the valence electrons are 2s²2p³ and they are positioned in a totally unpaired fashion in the 2p suborbital as 2s²2pₓ¹2pᵧ¹2pz¹.
Hence, the more stable alternative is more likely to occur and the electron is lost from the 2pₓ suborbital to make the monoatomic ion of the element acquire a +1 charge status too because of lost electron too.
Hope this Helps!!!
The octet rule states that the atoms of the elements bond to each other in an attempt to complete their valence shell with eight electrons. In other words, the atoms will tend to give up or share electrons to complete eight electrons in the valence shell through an ionic, covalent or metallic bond.
In other words, the goal is to have the closest noble gas electron configuration, thus having the last complete electron shell and acquiring stability.
So, in this case, to comply with the octet rule:
A. An element with the valence electron configuration 5s¹ would form a monatomic ion with a charge of +1. In order to form this ion, the element will lose one electron from the 5s subshell.
For an element with its valence electron at 5s¹, this means that there is one valence electron in the outermost shell of this atom and in the outermost suborbitals. To form a monatomic ion, it would be necessary between losing or gaining an electron and that ion is stable. It takes less energy to lose the electron of the suborbital 5s and acquire a charge of of +1, than to acquire an electron, because it forms the 5s² suborbital, which indicates empty 5p orbitals too and is therefore less stable.
Also, in this way, the octet rule is fulfilled.
B. An element with the valence electron configuration 2s²2p⁴ would form a monatomic ion with a charge of -2. In order to form this ion, the element will gain two electron into the 2p subshell(s).
After gain two electron the atom has eight electrons in its valence shell, giving it the same electronic configuration as a noble gas (2s²2p⁶). In this way, the octet rule is fulfilled and the ion is stable.
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Which of the following describes the change in atomic mass and atomic number during this reaction?
the rule of eight chemistry
Answer:
octet rule
Explanation:
It refers to the tendency of atoms to prefer to have eight electrons in the valence shell.
What is the mass defect of a mole of nuclei with 1.8 x 10^15 J/mol binding
energy?
Answer:
2.0 x 10^-2 kg/mol
Explanation:
What is the molarity of a solution in
which 3.8 moles of sodium chloride
(NaCl) is dissolved in water to a final
volume of 2.5 L?
Answer:
1.52M in NaCl
Explanation:
Molarity = moles solute / volume solution in Liters
=> molarity (M) = 3.8 moles / 2.5 Liters solution = 1.52 molar solution in NaCl
Answer: 1.52
Explanation:
H2O(g) + Cl2O(g) ↔ 2 HOCl(g) (a) Initially, 0.0555 mol H2O and 0.0230 mol Cl2O are mixed in a 1.00 L flask. At equilibrium, there is found to be 0.0200 mol of HOCl(g). Calculate the concentrations of H2O(g) and Cl2O(g) at equilibrium. (b) Using your results from part (a), calculate the equilibrium constant, Kc. (c) 1.0 mol pure HOCl is placed in a 2.0 L flask. Use your Kc from part (b) to calculate the equilibrium concentrations of H2O(g) and Cl2O(g).
Answer:
a)
[H₂O] = 0.0455M
[Cl₂O] = 0.0130M
[HOCl] = 0.0200M
b) Kc = 0.676
c) [H₂O] = [Cl₂O] = 0.177M
Explanation:
Based on the reaction:
H₂O(g) + Cl₂O(g) ⇄ 2HOCl(g)
Kc is defined as:
Kc = [HOCl]² / [H₂O][Cl₂O] For molar concentrations in equilibrium
As volume of the flask is 1.00L, the initial molar concentrations of H₂O and Cl₂O is 0.0555M and 0.0230M, respectively.
In equilibrium, the concentrations are:
[H₂O] = 0.0555M - X
[Cl₂O] = 0.0230M - X
[HOCl] = 2x = 0.0200M → X = 0.0100M
Where X is reaction coordinate
a) Concentrations in equilibrium are:
[H₂O] = 0.0455M
[Cl₂O] = 0.0130M
[HOCl] = 0.0200M
b) Replacing in Kc:
Kc = [0.0200]² / [0.0455][0.0130] = 0.676
c) Initial concentration of HOCl is 1.0mol / 2.0L = 0.50M. In equilibrium concentrations are:
[H₂O] = X
[Cl₂O] = X
[HOCl] = 0.50M - 2X
Replacing in Kc formula:
0.676 = [0.50-2X]² / [X][X]
0.676X² = 4X² - 2X + 0.25
0 = 3.324X² - 2X + 0.25
Solving for X:
X = 0.177M
X = 0.425M → False answer, produce negative concentrations.
As X = [H₂O] = [Cl₂O]; equilibrium concentrations of both compounds is 0.177M
At what temperature will a gas be, if you allow it to expand from its original volume of 756 mL at 65.0 °C to 1.40 L? (hint volume needs to be the same)
Answer:
120.4 gradius Celcius
Explanation:
Please see the step-by-step solution in the picture attached below.
Hope this answer can help you. Have a nice day!
HELP PLEASE ILL GIVE 25 pointsWhich of the following practices could help reduce erosion of water banks? a. buffer strips b. natural fertilizers and pesticides c. decrease in fossil fuel emissions d. all of the above Please select the best answer from the choices provided A B C D
Answer:
A. Buffer strips
Explanation:
The practice that could help reduce erosion of water banks is buffer strips.
What is erosion?Erosion is the action of surface processes that removes soil, rock or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited.
One of the practices that could be used to reduce the effect of erosion is buffer strips.
What buffer strips do is slow and filter storm runoff while helping to hold soil in place.
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What parts of the body are tested for rigor Mortis
PLEASE help! BRAINLIEST to correct answer!
Answer:
C
Explanation:
Answer:
I think its q
Explanation:
h is the Planck constant, c the speed of light
If a 1.45 M solution has 2.43 g HCl dissolved, what is the volume of solution? (Change g HCl into mol using molar mass)
Answer: The volume of solution is 0.0459 L
Explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution
[tex]Molarity=\frac{n}{V_s}[/tex]
where,
n = moles of solute
[tex]V_s[/tex] = volume of solution in L
moles of HCl (solute) = [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{2.43g}{36.5g/mol}=0.0666[/tex]
Now put all the given values in the formula of molality, we get
[tex]1.45M=\frac{0.0666}{V_s}[/tex]
[tex]V_s=\frac{0.0666}{1.45}=0.0459[/tex]
Therefore, the volume of solution is 0.0459 L
5 Which state of matter takes both the shape and volume of its container?
liquid
solid
gas
Answer:
gas
Explanation:
If you put gas in anything, it will occupy shape and volume.
Liquid only occupies shape of the container, whereas, solid doesn't occupy shape or volume because it maintains a fixed volume and shape.
A solution of KOH has a [OH-] concentration of 0.045 M. What is the pOH of the solution? *
1 point
-1.3
1.3
1.1
0.90
what is the answer?
Answer:
[tex]pOH=1.3[/tex]
Explanation:
Hello,
In this case, since pH is computed by knowing the concentration of hydrogen ions, one could compute the pOH by knowing the concentration of the hydroxyl ions as in this case which is 0.045M as shown below:
[tex]pOH=-log([OH^-])=-log([0.045])\\\\pOH=1.3[/tex]
Best regards.
Answer:
The pOH of the 0.045 M solution is 1.3
The second option (1.3) is correct
Explanation:
Step 1: Data given
Concentration [OH-] of KOH is 0.045 M
Step 2: Calculate pOH
pOH = -log[OH-]
pOH = -log (0.045)
pOH = 1.3
The answer:
The pOH of the 0.045 M solution is 1.3
The second option (1.3) is correct
I'll give you the brainiest please help.
Answer:
c
Explanation:
Which characteristic of a substance is considered a chemical property
Answer:
c
Explanation:
What is the correct IUPAC name for Ag₂S?
Answer:
Acanthite. MFCD00003406
Explanation:
What did the periodic table help scientists discover?
A. Elements that are radioactive
O B. Elements that are harmful
C. Elements not yet known to exist
D. Elements that no longer exist
There are various kind of elements that are present in periodic table. Some elements are harmful, some are radioactive, some are noble gases. Option C is correct option.
What is periodic table?
Periodic table is a table in which we find elements with properties like metals, non metals, metalloids and radioactive element arranges in increasing atomic number.
Periodic table help a scientist to know what are the different types of elements are present in periodic table so that they can discover the new elements that are not being discovered yet.
Periodic table is the best platform to have a look to all elements at once that are arranged in columns and groups mentioning their valencies, electronegativity and Ionisation energy symbols. Thus the option c is correct option.
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A sample of helium gas at room temperature is compressed from 100 cm3 to 20 cm3. Its new pressure is now 30 cm Hg. What was the original pressure of the gas?
Answer:
6 cm Hg
Explanation:
Boyles Law: P1V1=P2V2
(100 mL)(x)=(20 mL)(30 cm Hg)
x = 6 cm Hg
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[HCN]=0.09974 M
Kp=7.52
Calculate the partial pressure of HCN ?
Answer:
i don't understand
Explanation:
The largest contributed to water pollution is
Answer:
this si from google hope it helps
Explanation:
The Main Causes of Water Pollution in the U.S.
Runoff from Agricultural Operations. Agriculture represents one of the biggest sources of water pollution in the country. ...
Runoff and Nonpoint Source Pollution. ...
Industrial Activities. ...
Leakage from Underground Storage and Piping. ...
Leaking Sewers. ...
Vehicle Emissions. ...
Landfill Leakage. ...
Hazardous Waste.
Answer:
Runoff and Non-point Source Pollution.
Explanation:
it's caused by rainfall or snow-melt moving over and through the ground. As the runoff moves, it picks up and carries away natural and human-made pollutants, finally depositing them into lakes, rivers, wetlands, coastal waters and ground and NPS is it's abbreviation.
5) Low iron concentration (as low as 0.02 nM) in the open ocean limits phytoplankton growth. Preconcentration is required to determine such low concentrations. Trace Fe3 from a large volume of seawater is concentrated onto a 1.2 mL chelating resin column, the column is then rinsed with 30 mL of high purity water and eluted with 10 mL of 1.5 M high purity HNO3. a.) For each sample, seawater is passed through the column of 17 h at 10 mL./min. How much is the concentration of Fe3 in the 10 mL of HNO3 eluate increased by this preconcentration procedure
Answer:
Check the explanation
Explanation:
Sample volume V= 10 mL/min x 17 h x 60 min/h / 1000 mL/L = 10.2 L
The concentration is increased
10200 mL (sample volum) / 10 mL (eluted sample) = 1020 times.
57x10-9 M / 1020 = 5.6x10-12 M
1.5 M HNO3 will contain ≤ 2ppm x (1.5M/15.7M ) ≤ 0.190 ppm ≤ 190 ppb
Ignoring this is reagent impurity and calculating for sea water
≤ 190 ppb /1020 = 0.186 ppb = 0.186 x 10-9g/mL = 0.186 x 10-6g/L =
0.186 x 10-6g/L / 56 g/mol = 0.003 x10-6 M = 3 nM
Two identical light bulbs are connected to a battery in a series circuit.
An ammeter is wired into the circuit at measures a current of the
battery to be 0.5 Amps. The two light bulbs are then wired in parallel.
The ammeter shows that the current:
Answer:
0.10 amps
Explanation:
What is the molar mass of ethanol (C2H60)?
Answer:
46.07 g/mol is the molar mass of ethonal
If a solution has a pOH=12, what is its pH?
Answer:
2
Explanation:
pH+pOH=14
- Hope that helps! Please let me know if you need further explanation.
Answer:
2
Explanation:
Ph+PoH=14
Sometimes in lab we collect the gas formed by a chemical reaction over water (see sketch at right). This makes it easy to isolate and measure the amount of gas produced.
Suppose the CO gas evolved by a certain chemical reaction taking place at 55 degree C is collected over water, using an apparatus something like that in the sketch, and the final volume of gas in the collection tube is measured to be 117 ml.
Calculate the mass of CO that is in the collection tube. Round your answer to 2 significant digits. You can make any normal and reasonable assumption about the reaction conditions and the nature of the gases.
Answer:
The correct answer is 0.12 grams.
Explanation:
The mass of carbon monoxide or CO collected in the tube can be determined by using the ideal gas equation, that is, PV = nRT.
Based on the given question, P or the pressure of the gas is given as 1 atm, volume of the gas collected in the tube is 117 ml or 0.117 L.
The number of moles or n can be determined by using the equation, mass/molar mass.
R is the universal gas constant, whose value is 0.0821 L atmK^-1mol^-1, and temperature is 55 degree C or 328 K (55+273).
On putting the values we get:
n = PV/RT
= (1 atm*0.117 L) / (0.0821 L atmK^-1mol^-1 * 328 K)
= 0.0043447 mol
Therefore, mass of CO will be moles * molar mass of CO
= 0.0043447 mol * 28 g/mol
= 0.12 g
18.35 mL of an HCN solution were titrated with 35.4mL of a 0.268M NaOH solution to reach the equivalence point. What is the molarity of the HCN solution
Answer:
0.517
Explanation:
HCN + NaOH → NaCN + H2O [balanced as written]
(35.4 mL) x (0.268 M NaOH) x (1 mol HCN / 1 mol NaOH) / (18.35 mL HCN) = 0.517 M HCN
Answer: 0.517
Explanation:
which would dissolve faster individual salt crystals a big block of salt
Answer:
Table salt (the iodine isn't important) consists of much smaller particles than rock salt and therefore has a much higher ratio of surface area to mass. Since chemical reactions occur at surfaces,the smaller table salt particles will dissolve far more quickly than the larger rock salt.
Explanation:
Answer:
Individual salt crystals
Explanation:
A given quantity of solute dissolves faster when it is ground into small particles than if it is in the form of a large chunk because more surface area is exposed.
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