Answer:
100ml x 0.774
divide by 4
x by 8
Which process is not reversible?Dissolving sugar in water Burning butane in a candle lighterMelting waxExtracting iron metal from iron (III) oxide
Answer
The process that is NOT reversible is Burning butane in a candle lighter
Explanation
All other processes can be reversed
What is neutralization reaction? Use an example to describe the components of neutralization reaction
1) Neutralization reaction.
In this type of reaction an acid and a base react to form a salt and water. In the course of the reaction H+ and OH- are produced. Afterward, they combine to produce water.
2) Example.
Acid: HCl
Base: NaOH
Salt: NaCl
[tex]\text{HCl}+\text{NaOH}\rightarrow NaCl+H_2O[/tex]In a lab experiment, 7.97 g of phosphorus reacts with bromine to form 69.65 g of phosphorus tribromide. How much phosphorus tribromide would be formed if 12.05 g of phosphorus reacted with 61.68 g of bromine? answer:______gi put what i got in the image and it is wrong sorry
1) List the known and unknown quantities.
First experiment:
Reactants
Phosphorus: 7.97 g.
Bromine: excess.
Product
Phosphorus tribromide: 69.65 g.
Second experiment
Reactants
Phosphorus: 12.05 g.
Bromine: 61.68 g.
Product
Phosphorus tribromide: unknown.
2) Write and balance the chemical equation.
[tex]2P+3Br_2\rightarrow2PBr_3[/tex]3) Convert the masses.
3.1-Convert the mass of P to moles of P.
The molar mass of P is 30.97 g/mol.
[tex]mol\text{ }P=12.05\text{ }g\text{ }P*\frac{1\text{ }mol\text{ }P}{30.97\text{ }g\text{ }P}=0.38909\text{ }mol\text{ }P[/tex]3.2-Convert the mass of Br to moles of Br.
The molar mass of Br2 is 159.8080 g/mol.
[tex]mol\text{ }Br_2=61.68\text{ }g\text{ }Br_2*\frac{1\text{ }mol\text{ }Br_2}{159.8080\text{ }g\text{ }Br_2}=0.38596\text{ }mol\text{ }Br_2[/tex]4) Which is the limiting reactant?
4.1-How many moles of Br2 do we need to use all of the P?
The molar ratio between Br2 and P is 3 mol Br2: 2 mol P.
[tex]mol\text{ }Br_2=0.38909\text{ }mol\text{ }P*\frac{3\text{ }mol\text{ }Br_2}{2\text{ }mol\text{ }P}=0.583635\text{ }mol\text{ }Br_2[/tex]We need 0.583635 mol Br2 and we have 0.38596 mol Br2. We do not have enough Br2. This is the limiting reactant.
4.2-How many moles of P do we need to use all of the Br2?
The molar ratio between Br2 and P is 3 mol Br2: 2 mol P.
[tex]mol\text{ }P=0.38596\text{ }mol\text{ }Br_2*\frac{2\text{ }mol\text{ }P}{3\text{ }mol\text{ }Br_2}=0.25731\text{ }mol\text{ }P[/tex]We need 0.25731 mol P and we have 0.38909 mol P. We have enough P. This is the excess reactant.
5) Moles of phosphorus tribromide produced from the limiting reactant.
Limiting reactant: 0.38596 mol Br2.
The molar ratio between Br2 and PBr3 is 3 mol Br2: 2 mol PBr2.
[tex]mol\text{ }PBr_2=0.38596\text{ }mol\text{ }Br_2*\frac{2\text{ }mol\text{ }PBr_3}{3\text{ }mol\text{ }Br_2}=0.25731\text{ }mol\text{ }PBr_3[/tex]6) Conver the moles of Pbr3 to mass of PBr3.
The molar mass of PBr3 is 270.6858 g/mol.
[tex]g\text{ }PBr_3=0.25731\text{ }PBr_3*\frac{270.6858\text{ }g\text{ }PBr_3}{1\text{ }mol\text{ }PBr_3}=69.6502\text{ }g\text{ }PBr_3[/tex]The mass of PBr3 produced in the reaction is 69.65 g PBr3.
.
How many molecules of carbon dioxide, CO2, comprise 1.22 moles?
How many molecules of carbon dioxide, CO₂, comprise 1.22 moles?
According to Avogadro's Number we have 6.02 * 10^23 molecules in one mol of molecules. So:
1 mol of CO₂ = 6.02 * 10^23 molecules of CO₂
Then:
1.22 moles of CO₂ * 6.02 * 10^23 molecules of CO₂ / 1 mol of CO₂ = 7.34 * 10^23 molecules of CO₂
There are 7.34 * 10^23 molecules of CO₂ in 1.22 moles of it
The phenolic indicator (ln-OH) has approximately the same pKa as a carboxylic acid. Which H is the most acidic proton in ln-OH? Circle or otherwise indicate the most acidic proton. Explain why that H is the most acidic proton in ln-OH (i.e. what makes its conjugate base well stabilized)?
The most acidic hydrogen atom is the hydrogen atom that have been bonded to the oxygen atom.
What is an acidic proton?
We say that a proton is an acidic proton if the proton is able to leave very easily from the rest of the compound. We know that there are several factors that could make a proton that is found in a molecule to become a labile or an acidic proton. The acidity of a proton largely stem from the fact that electron density between the hydrogen atom and the atom to which it is bonded is weak. As such, the bond is weakened by the lengthening of the bond and a consequent lability of the attached hydrogen atom as discussed here.
In the compounds as shown, the most acidic proton is the proton that is attached to the oxygen atom. This is because, the extensive conjugation in the molecule withdraws electrons from the 0-H bond and this makes the hydrogen atom to become labile or acidic.
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How much water needs to be added to a 8.6317 M NaCl solution to obtain a 1.0421 M solution, if you start with 4.7869 liters of solution?
The amount of water needed to be added to a 8.6317 M NaCl solution to obtain a 1.0421 M solution starting with 4.7869 liters of solution would be 34.8629 L.
DilutionThe problem here has to do with dilution. The dilution principle states that the number of moles of solute in a solution is constant before and after dilution.
In other words, the dilution principle can be mathematically expressed as:
[tex]m_1v_1[/tex] = [tex]m_2v_2[/tex].
Where [tex]m_1[/tex] and [tex]m_2[/tex] are molarities before and after dilution; [tex]v_1[/tex] and [tex]v_2[/tex] are volumes before and after dilution.
In this case: [tex]m_1[/tex] = 8.6317 M, [tex]m_2[/tex]= 1.0421 M, [tex]v_1[/tex]= 4.7869 L. We are to determine v2.
[tex]v_2[/tex] = [tex]m_1v_1[/tex]/ [tex]m_2[/tex]
= 8.6317x4.7869/1.0421
= 39.6498 L
If the final volume of the solution is 39.6498 L and the starting volume is 4.7869, then the amount of water needed can be calculated as:
39.6498 - 4.7869 = 34.8629 L
Thus, the amount of water that will be added to the original solution in order to arrive at the diluted solution is 34.8629 L.
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Consider the reaction: 2H2₂0 +
energy --> 2H2 + O₂
exothermic because absorbing
energy
endothermic because absorbing
energy
endothermic because releasing
energy
exothermic because releasing
energy
Explanation:
endothermic because absorbing
energy
H2O is absorbing heat to release hydrogen and oxygen gas. any reaction that requires energy from outside is endothermic.
Why does an atom want to form an octet or duet?And yes I know these rules and I know that it “wants” a stable electronic configuration and a filled shell.
Answer
An atom wants to form an octet or duet because an atom always wants to be in the most stable form. For any atom, stability is achieved by following the octet rule or duet rule, which is to say all atoms (with a few exceptions) want 8 electrons (octet) or 2 electrons (duet) in their outermost electron shell just like noble gases.
In a different titration, a solid sample containing some Fe2+ ion weighs 1.705g. It requires 36.44 mL, 0.0244 M KMnO4 to titrate the Fe2+ in the dissolved sample to a pink end point.
a. How many moles MnO4 ion are required?
b. How many moles Fe2+ are there in the sample
c. How many grams of Fe are there in the sample?
d. What is the percent Fe in the sample?
The accurate responses are;
a) Number of moles of permanganate ion = 8.89 * 10^-4 moles
b) Number of moles of iron = 4.4 * 10^-3 moles
c) Mass of iron in the sample = 0.25 g
d) Percentage of iron in the sample = 14.7 %
What is titration?The term titration refers to the kind of reaction in which the amount of substance can be obtained by the accurate determination of the volumes of the substances that have reacted in the process.
a) The number of moles of the permanganate ion that are involved is obtained from;
36.44 /1000 L * 0.0244 M = 8.89 * 10^-4 moles
b) Given that the reaction is 1:5 in the mole ratio of the permanganate ion and the iron III ion
1 mole of permanganate reacts with 5 moles of iron II
8.89 * 10^-4 moles reacts with 8.89 * 10^-4 moles* 5 moles/ 1 mole
= 4.4 * 10^-3 moles
c) Mass of the iron II ion in the sample = 4.4 * 10^-3 moles * 56 g/mol = 0.25 g
d) Percent of the iron in the sample = 0.25 g/1.705g * 100/1
= 14.7 %
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9) How many ATOMS of fluorine are there in 3.71 moles of nitrogen trifluoride (NF3)? (Hint: this requires two conversions)
The number of atoms of fluorine present in 3.71 moles of nitrogen trifluoride, NF₃ is 6.7×10²⁴ atoms
How to determine the number of atomsWe'll begin by obtaining the number of moles of fluorine in 3.71 moles of nitrogen trifluoride NF₃. This can be obtained as follow:
1 mole of nitrogen trifluoride, NF₃ contains 3 moles of F
Therefore,
3.71 moles of nitrogen trifluoride, NF₃ will contain = 3.71 × 3 = 11.13 moles of F
Finall, we shall determine the number of atoms of fluorine pressnt in the compound as follow:
From Avogadro's hypothesis,
1 mole of fluorine = 6.02×10²³ atoms
Therefore,
11.13 moles of fluorine = (11.13 moles × 6.02×10²³ atoms) / 1 mole
11.13 moles of fluorine = 6.7×10²⁴ atoms
Thus, from the calculations made above, we can conclude that the number of atoms of fluorine present is 6.7×10²⁴ atoms
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Help I am not sure how to do this number 8
Answer: The temperature of the gas sample under the conditions given is 30.313 K
Explanation:
The question requires us to determine the temperature, in Kelvins, of a C2H6 gas sample with the following mass, volume and pressure:
mass of C2H6 = m = 561.51g
volume of gas = V = 47.048L
pressure of gas = P = 100.03 kPa
To solve this problem, we can apply the equation of ideal gases rearranged to calculate the temperature, as shown below:
[tex]PV=nRT\rightarrow T=\frac{PV}{nR}[/tex]where T is the temperature we want to calculate, P corresponds to the pressure of the gas, V is its volume, n is its number of moles and R is the constant of gases (8.314 kPa.L/mol.K).
Note that the only valye that was not provided by the question was the number of moles. We can determine the number of moles n considering the mass of the sample given (561.51g) and the molar mass of the gas C2H6, which we can determine from the atomic masses of C and H.
The atomic masses of C and H are 12.011 and 1.0078 amu, thus we can calculate the molar mass of C2H6 as:
[tex]molar\text{ mass \lparen C}_2H_6)=2\times12.011+6\times1.0078=30.069g/mol[/tex]Now that we know the mass of the gas sample (561.51 g) and the molar mas of the gas (30.069 g/mol), we can determine the number of moles of gas as it follows:
[tex]\begin{gathered} number\text{ of moles = }\frac{mass\text{ \lparen g\rparen}}{molar\text{ mass \lparen g/mol\rparen}}\rightarrow n=\frac{m}{M} \\ \\ n=\frac{561.51g}{30.069g/mol}=18.674mol \end{gathered}[/tex]Therefore, the number of moles of C2H6 gas that we need to consider is 18.674 moles.
Next, we can apply the equation of ideal gases to calculate the temperature of the gas:
[tex]\begin{gathered} T=\frac{PV}{nR} \\ \\ T=\frac{(100.03kPa)\times(47.048L)}{(18.674mol)\times(8.314kPa.L/mol.K)}=30.313K \end{gathered}[/tex]Therefore, the temperature of the gas sample under the conditions given is 30.313 K.
April investigated a crime scene where a gunshot sent blood through the air and it splattered on the wall. How would a forensic scientist BEST categorize this blood stain?
A.
transfer
B.
impact
C.
circular
D.
passive
The forensic scientist best categorize this blood stain by impact. Thus option B is correct.
What is forensic science?Forensic science is defined as the application of science to criminal and civil laws, with a focus on the criminal side during a criminal investigation as defined by the legal requirements of admissible evidence and criminal procedure.
There are various laws and principles of forensic science.
The laws of individuality and progressive change.Lockard's Exchange PrinciplePrinciple of Comparison: This law is crucial for laboratory investigations.Analytical Principle.The law of probabilityCircumstantial facts lawThus, the forensic scientist best categorize this blood stain by impact. Thus option B is correct.
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2- The vapor pressure of water at 80°C is 355 torr, Calculate the vapor
pressure of an aqueous solution made by dissolving 50 gm of ethylene
glycol (C₂H5O₂) in 50 gm of water. What is the vapor pressure lowering of
water in this solution?
The vapor pressure lowering of water in this solution is 1165 torr.
What is vapor pressure?
The pressure that a vapour exerts on its condensed phases in a closed system at a specific temperature is known as the vapour pressure or equilibrium vapour pressure. An indicator of a liquid's evaporation rate is the equilibrium vapour pressure. It has to do with how easily liquid-borne particles tend to elude detection (or solid). Volatile is a term used to describe a chemical that, at room temperature, has a high vapour pressure. Vapor pressure is the force that a vapour cloud exerts over a liquid surface. The kinetic energy of a liquid's molecules increases along with the temperature. The number of molecules vaporising also rises as a function of the molecules' rising kinetic energy, which raises the vapour pressure.
the vapor pressure of water and the mixture is 355 torr and 760 torrs. Therefore, the value of vapor pressure of oxygen would be,
Ptotal=PO2+PH2O
760=PO2+355
760−355=PO2
405=PO2
So, at the temperature, the vapor pressure of Ethylene is 405 torr.
When volume reduces to 50ml, the pressure of the oxygen would be,
P1V1=P2V2
where P1 and P2 are the pressure and V1 and V2 are the volumes.
P1V1=P2V2
P1V1/V2=P2
405×100 / 50=P2
810=P2
So, when the volume is 50ml the vapor pressure of the oxygen is 810 torr.
Now the total pressure of water-saturated oxygen at 50 ml volume is,
Ptotal=PO2+PH2O
Ptotal=810+355
Ptotal=1165
So, the total vapor pressure is 1165 torr.
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This question is to the Brainly employees: Can you please make it to where it doesn't cover the answer because you have to pay for it. Please and thank you sir or mam.
Answer:
right
Explanation:
What is TRUE about expert witnesses?
A.
They offer personal and professional knowledge.
B.
They are not allowed to practice their testimony.
C.
They are required to link all evidence to the crime.
D.
They have all written a book about their area of expertise.
The true statement about is expert witnesses that they are required to link all evidence to the crime.
So, option C is correct.
Who are expert witnesses?An expert witness is described particularly in common law countries such as the United Kingdom, Australia, and the United States, is a person whose opinion by virtue of education, training, certification, skills or experience, is accepted by the judge as an expert.
Expert witnesses are required or expected to to link all evidence to the crime.
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Which diagram shows the correct way to represent an ionic compound of magnesium oxide?
Answer:
C.
Explanation:
The correct way to write the diagram of an ionic compound is:
- Use brackets by writing inside them, the symbol of each element separately.
- Draw the symbol and the number o the charge of each one, negative (-) add positive +()., in this case it is +1 for Mg (because Mg lost an electron) and -1 for O (because O won an elec).
Calcium like to lose how many electron/s to form an ion?Group of answer choices123cannot determine
Answer: the best option to answer the question is the second one (or letter B), "2"
Explanation:
The question requires us to identify how many electrons a calcium (Ca) atom would lose to form an ion.
We can analyze the electron configuration of Ca to understand how many electrons it would lose.
The atomic number of Ca is 20, thus its electron configuration is as it follows:
[tex]1s^2\text{ 2}s^2\text{ 2}p^6\text{ 3}s^2\text{ 3}p^6\text{ 4}s^2[/tex]From the electron configuration, we can see that Ca presents 2 electrons in its valence shell (4s2). To achieve stability, it is easier for Ca to lose these two electrons and form a Ca2+ ion.
Therefore, the best option to answer the question is the second one (or letter B), "2".
10. What is the Arrhenious definition for acids and bases? Why do we use thisdefinition?
ANSWER
Definition of an acid; is a substance that produced hydrogen ions (H+) as the only positive ion when dissolved in water or in an aqueous solution. it increases the concentration of hydrogen ions in an aqueous solution.
Definition of the base; are hydroxide compounds that give hydroxide ion (OH-) on dissociation in water. it increases the concentration of hydroxide ions in an aqueous solution.
Why do we use the definition: it helps us to understand the acid-base properties of substances in an aqueous medium. neutralization, hydrolysis, and strength of acids and bases
EXPLANATION:
Arrhenius defined acid and base in the following way
According to Arrhenius, he defined an acid as a substance that produced hydrogen ions (H+) as the only positive ion when dissolved in water or in an aqueous solution. it increases the concentration of hydrogen ions in an aqueous solution.
[tex]\begin{gathered} \text{According to Arrhenius} \\ HA_{(aq)}\rightleftarrows H^{+_{}}_{(aq)}+A^-_{(aq)} \end{gathered}[/tex]Bases are hydroxide compounds that give hydroxide ion (OH-) on dissociation in water. it increases the concentration of hydroxide ions in an aqueous solution.
[tex]\text{BOH}_{(aq)}\rightleftarrows B^+_{(aq)}+OH^-_{(aq)}[/tex]Arrhenius's definition of acid and base is still in use because it helps us to understand the acid-base properties of substances in an aqueous medium. neutralization, hydrolysis, and strength of acids and bases
Sulfur burns in oxygen to form sulfur dioxide. Write a skeleton equation for this chemical reaction.
A skeletal chemical equation is a representation of a chemical reaction using chemical formulae of reactants and products.
Sulfur = S
Oxygen = O
Sulfur dioxide = SO2
The skeleton equation is:
[tex]S+O_2\text{ }\Rightarrow SO_2[/tex]Here the skeleton equation = balanced equation.
What is 4.8829g + 121.3 g + 9.384 g . ensure your answer confiding to rules regarding significant figures
Answer:
[tex]135.6g[/tex]Explanation:
Here, we want to sum the given values, then give an answer to the correct significant figures
The correct significant figure for addition operation is the significant figure of the number that has the lowest count of values after the decimal places
Looking at the values, the number with the lowest significant figure after the decimal value is 121.3
Thus, our answer will have a value with 1 significant figure after the decimal place
We have it that:
[tex]\begin{gathered} \text{ 4.8829 + 121.3 + 9.384 = 135.5669g} \\ which\text{ finally is:} \\ 135.6g \end{gathered}[/tex]
What is TRUE about expert witnesses?
A.
They offer personal and professional knowledge.
B.
They are not allowed to practice their testimony.
C.
They are required to link all evidence to the crime.
D.
They have all written a book about their area of expertise.
The statement they offer personal and professional knowledge is TRUE about expert witnesses (Option A).
What is the role performed by witnesses?The specific role performed by witnesses in a given case is to answer questions associated with a subject matter, which are associated with evidence to confirm or reject a given hypothesis.
Therefore, with this data, we can see that the work performed by witnesses is to provide answers in a given subject matter, which is information that may be used as empirical evidence to confirm or reject a given process.
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What mass of oxygen can be obtained from heating 163.27G of potassium chlorate?
Step 1
The reaction involved:
2 KClO3 => 2 KCl + 3 O2 (completed and balanced)
------------
Step 2
Data provided:
Mass of KClO3 = 163.27 g
---
Data needed:
The molar mass of:
KClO3) 122.6 g/mol
O2) 32.00 g/mol
-------------
Step 3
Procedure:
By stoichiometry,
2 KClO3 => 2 KCl + 3 O2
2 x 122.6 g KClO3 ------ 3 x 32.00 g O2
163.27 g KClO3 ------ X
X = 163.27 g KClO3 x 3 x 32.00 g O2/2 x 122.6 g KClO3
X = 63.92 g
Answer: 63.95 g (the nearest value)
Jade throws a horseshoe toward a stake from the same starting point three different times. She tries to throw the horseshoe with the same amount of force each time. Jade measures the distance each horseshoe lands from the stake. Which distances did Jade likely measure?
Responses
100 in., 200 in., 300 in.
5 in., 25 in., 50 in.
2 in., 100 in., 120 in.
11 in., 12 in., 13 in
Since Jade tried to throw the horseshoe with the same amount of force, the likely distances that Jade measured would be 11 in., 12 in., 13 in. The last option.
Force and distanceThe distance that the horseshoe thrown by Jade travels is a measure of the amount of force that she applies. The more the force, the longer the distance.
However, Jade tried to ensure that the same amount of force is used the 3 times she threw the horseshoe. The consequence is that the distance of the horseshoe from the stake will not vary much in all the 3 throws.
If the distances vary significantly, it means the amount of force used by Jade also differs significantly.
Thus, the only distances that could be a reflection of the relatively constant force used by Jade to throw the horseshoe are 11 in., 12 in., 13 in.
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strategies for controlling carbon monoxide are in conflict with strategies for controlling oxides of nitrogen .
Answer:
I do not know how to answer this question. Is it even a question?
Explanation:
Which hydrogen below will have the greatest partial positive charge?Group of answer choicesHIHClHBrHFcannot determine
The hydrogen bonded to the most electronegative element will have the greatest partial positive charge. This is because electronegativity corresponds to the ability of the nucleus of an atom to attract the electrons involved in a chemical bond.
So the more electronegative, the more partial negative charge the atom will have.
Linus Pauling created a scale of the most electronegative elements, which can be of help in determining the intensity of polarization of different bonds:
F > O > N > C > Br > I > S > C > P > H
In this case, F is the most electronegative element.
So hydrogen will have the greatest partial positive charge bonded to F.
Answer: HF
what is the molar mass of anhydrous solid, mol
what is the molar mass of anhydrous solid, mol?
The half-life of phosphorus−33 is 25.0 days. How much of a 2.7−oz sample of phosphorus−33 will remain after 150 days?
If phosphorus-33 have an half-life of 25 days the amount of phosphorus-33 that will remain after 150 days is 0.042 oz.
What is half-life?Half-life is the time taken for half the sample of a radioactive substance to decay.
To calculate the amount of phosphorus-33 that will remain after 150 days, we use the formula below.
Formula:
R' = R/[tex]2^{T/t}[/tex]........ Equation 1Where:
R = Original amount of phosphorus-33R' = Amount of phosphorus-33 that will remain after 150 daysT = Total timet = half-lifeFrom the question,
Given:
R = 2.7 ozT = 150 dayst = 25 daysSubstitute these values into equation 1
R' = 2.7/([tex]2^{150/25[/tex])R' = 2.7/[tex]2^{6}[/tex]R' = 2.7/64R' = 0.042 ozHence the amount of phosphorus-33 that will remain after 150 days is 0.042 oz.
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can someone please help me with 28 A!
Answer: The answer for 28 A is [tex][He]2s^2 2p^2[/tex]
28 B is [tex]1s^2 2s^2 2p^1[/tex]
What is the balanced, net ionic equation for the reaction described below?Aqueous sodium phosphate and aqueous iron (III) chloride react to produce aqueous sodium chloride and solid iron (III) phosphate.
A net ionic equation is the one that only includes the ions that are involved in the formation of the solid.
According to the information the solid formed is iron (III) phosphate, and the ions involved are Fe3+ and PO43-.
It means that the net ionic equation is:
[tex]Fe_{(aq)}^{3+}+PO_{4(aq)}^{3-}\rightarrow FePO_{4(s)}[/tex]The correct answer is the second choice.
How many moles of solute are present in 250 mL of 4.00 M HCI?
Answer:
Answer. There are 0.1 moles of solute in 250 mL of 0.4 M solution.