Answer:
19000 torr
Explanation:
From the question given above, the following data were obtained:
Initial volume (V₁) = 0.150 L
Initial pressure (P₁) = 1520 torr
Final volume (V₂) = 0.012 L
Temperature = constant
Final pressure (P₂) =?
The final pressure of the gas can be obtained by using the Boyle's law equation as illustrated below:
P₁V₁ = P₂V₂
1520 × 0.150 = P₂ × 0.012
228 = P₂ × 0.012
Divide both side by 0.012
P₂ = 228 / 0.012
P₂ = 19000 torr
Thus, the final pressure of the gas is 19000 torr
6ooo kg into quintal
Answer:
60 q
Explanation:
The conversion factor is 100; so 1 quintal = 100 kilograms. In other words, the value in q multiply by 100 to get a value in kg.
You used a variety of media with a NaCl concentration ranging from 0.5% to 15%. Which of these media would have the lowest water activity?
a. 0.5% NaCl
b. 15% NaCl
c. 10% NaCl
d. 5% NaCl
Answer:
Explanation:
B
A piece of solid tin is submerged in silver nitrate solution a reaction occurs producing tin(IV) nitrate solution and solid silver
Write a word equation write a skeleton equation write a balanced chemical equation
Answer:
Tin + silver trioxonitrate V -------->Tin IV nitrate + silver
Explanation:
The term word equation refers to an equation in which the reactants and products are written in words rather than chemical symbols.
Note than tin is above silver in the electrochemical series hence silver will be displaced by tin as follows;
Tin + silver trioxonitrate V -------->Tin IV nitrate + silver
To what volume (in mL) would you need to dilute 20.0 mL of a 1.40 M solution of LiCN to make a 0.0880 M solution of LiCN?
Answer:
To 318.18 mL would you need to dilute 20.0 mL of a 1.40 M solution of LiCN to make a 0.0880 M solution of LiCN
Explanation:
Dilution is the reduction of the concentration of a chemical in a solution and consists simply of adding more solvent.
In a dilution the amount of solute does not vary. But as more solvent is added, the concentration of the solute decreases, as the volume (and weight) of the solution increases.
In a solution it is fulfilled:
Ci* Vi = Cf* Vf
where:
Ci: initial concentration Vi: initial volume Cf: final concentration Vf: final volumeIn this case:
Ci= 1.40 MVi= 20 mLCf= 0.088 MVf= ?Replacing:
1.40 M* 20 mL= 0.088 M* Vf
Solving:
[tex]Vf=\frac{1.40 M* 20 mL}{0.088 M}[/tex]
Vf= 318.18 mL
To 318.18 mL would you need to dilute 20.0 mL of a 1.40 M solution of LiCN to make a 0.0880 M solution of LiCN
what is the mass of insoluble calcium phosphate produced from .555 grams of calcium chloride
Answer:
0.518 g
Explanation:
Step 1: Write the balanced equation
3 CaCl₂ + 2 H₃PO₄ ⇒ Ca₃(PO₄)₂ + 6 HCl
Step 2: Calculate the moles corresponding to 0.555 g of CaCl₂
The molar mass of CaCl₂ is 110.98 g/mol.
0.555 g × 1 mol/110.98 g = 5.00 × 10⁻³ mol
Step 3: Calculate the moles of Ca₃(PO₄)₂ produced
5.00 × 10⁻³ mol CaCl₂ × 1 mol Ca₃(PO₄)₂/3 mol CaCl₂ = 1.67 × 10⁻³ mol Ca₃(PO₄)₂
Step 4: Calculate the mass corresponding to 1.67 × 10⁻³ moles of Ca₃(PO₄)₂
The molar mass of Ca₃(PO₄)₂ is 310.18 g/mol.
1.67 × 10⁻³ mol × 310.18 g/mol = 0.518 g
define a molecular mass and mole
Answer:
A molecular mass is mass on the substance and mole is a unit of substance such as atoms and electrons.
Explanation:
A molecular mass is the mass of a molecule of the substance and is called as molecular weight. Molar mass is measured in moles. Mass of one mole is 6.022x10²³ particles and is expressed in grams. The molar mass is said to be the mass of the given substance that is divided by the amount of the substance and s expressed in g/ml.Molecular mass: A molecule's molecular mass is equal to the sum of all of the atoms' individual atomic masses. It establishes the molecular mass of a single unit.
Example:
Molecular mass of O2 = 32 atomic mass units
Mole: A mole is [tex]6.02214076 x 10^2^3[/tex]of any chemical unit, including atoms, molecules, ions, and others. Due to the large number of atoms, molecules, or other components that make up any material, the mole is a useful measure to utilize. The initial definition of the mole was the number of atoms in 12 grams of carbon-12.
Learn more about mole here:https://brainly.com/question/22540912
Compound X has the same molecular formula as butane but has a different boiling point and melting point. What can be concluded about Compound X?
A It is a four-carbon alkene or alkyne.
B It is an optical isomer of butane.
C It is a geometric isomer of butane.
D It is a structural isomer of butane.
need this for gradpoint:)
Answer:
d
Explanation:
A hypnotist's watch hanging from a chain swings back and forth every 0.98 s. What is the frequency (in Hz) of its oscillation?
Answer:
1.02 Hz
Explanation:
frequency= (1/t) = (1/0.98) = 1.02 hz
How to calculate the actual volume (ml) of water removed from the burette with water
density 1 g/ml:
i. 5mL of water removed
Answer:
Explanation:
The density of pure water is 1 gram per 1 milliliter or one cubic cm. By knowing the density of water we can use it in dilution equations or to calculate the specific gravity of other solutions.
It can also help us determine what other substances are made of using the water displacement experiment. This is done by observing how much water is displaced when an object is submerged in the water. As long as you know the density of the water, the mass of the object being submerged and the volume of increase you can calculate the density of the object.
This was done by the great Archimedes in discovering what composed the kings crown.
What happens in a flame test?
A. Electrons are excited to higher energy levels and their emissions
are observed.
B. Impurities in a sample are burned off in the flame until a pure
sample remains
C. Electrons are ejected from atoms when a sample is burned in the
flame.
D. A sample is melted in a flame to determine how much energy was
In a flame test electrons are excited to higher energy levels and their emissions are observed. Therefore, option A is correct.
What is flame test ?The flame test is used to visually identify the identity of an unknown metal or metalloid ion based on the properties color the salt turns in the flame of a bunsen burner.
The color of light emitted depends on the energy emitted by an electron returning to its original state.
The flame's heat converts metal ions into atoms, which become excited and emit visible light. In a flame test electrons are excited to higher energy levels and their emissions are observed.
Thus, option A is correct.
To learn more about the flame test, follow the link;
https://brainly.com/question/6357832
#SPJ1
Write an equilibrium expression for each chemical equation involving one or more solid or liquid reactants or products.
Answer:
a.
[tex]Keq=\frac{[HCO_3^-][OH^-]}{[CO_3^{2-}]}[/tex]
b.
[tex]Keq=[O_2]^3[/tex]
c.
[tex]Keq=\frac{[H_3O^+][F^-]}{[HF]}[/tex]
d.
[tex]Keq=\frac{[NH_4^+][OH^-]}{[NH_3]}[/tex]
Explanation:
Hello there!
In this case, for the attached reactions, it turns out possible for us to write the equilibrium expressions by knowing any liquid or solid would be not-included in the equilibrium expression as shown below, with the general form products/reactants:
a.
[tex]Keq=\frac{[HCO_3^-][OH^-]}{[CO_3^{2-}]}[/tex]
b.
[tex]Keq=[O_2]^3[/tex]
c.
[tex]Keq=\frac{[H_3O^+][F^-]}{[HF]}[/tex]
d.
[tex]Keq=\frac{[NH_4^+][OH^-]}{[NH_3]}[/tex]
Regards!
Me please answer as follows
Answer:
no reaction occurs .that is no product
Is the following sets of quantum numbers valid? Give suitable reason. n=3,l=2,m=3,s=+1/2
Answer:
The set of quantum numbers is not valid
Explanation:
There are four sets of quantum numbers;
1) Principal quantum number (n) which takes on integer values from n = 1,2,3 .......
2) Azimuthal quantum number (l) which takes on values 1, 2, ....(n - 1)
3) Magnetic quantum numbers (ml) which takes on values from (-l) to (+l)
4) spin quantum number (ms) which takes on values of ±1/2.
From the above, we can see that m can not have a value of 3 when l =2 because m has values between (-l) to (+l). Thus, the sets of quantum numbers is not valid.
An oxygen atom with three missing electrons is released near the Van de Graaff generator. What is its energy in MeV at this distance
Answer:
(a) The potential near its surface is 45 * 10^6 V.
(b) The distance from which its center is the potential 1.00 MV is 45 m.
(c) Its energy in MeV when the atom is at the distance found in part b is 132 MeV.
Explanation:
Note: This question is not complete. The complete question is therefore provided before answering the question.
A research Van de Graaff generator has a 2.00-m diameter metal sphere with a charge of 5.00 mC on it. (a) What is the potential near its surface?
(b) At what distance from its center is the potential 1.00 MV?
(c) An oxygen atom with three missing electrons is released near the Van de Graaff generator. What is its energy in MeV when the atom is at the distance found in part b?
The explanation of the answer is now provided as follows:
(a) What is the potential near its surface?
Q = Charge on the generator = 5 mC = 5 * 10^(-3)C
r = Sphere radius = 2 / 2 = 1 m
k = Constant of the electric force = 9 * 10^(9) N . m^2 / C^2
Therefore, the electric potential of a point charge can be calculated as follows:
V = kQ / r
V = (9 * 10^9 * 5 * 10^(-3)) / 1 = 45 * 10^6 V
Therefore, the potential near its surface is 45 * 10^6 V.
(b) At what distance from its center is the potential 1.00 MV?
This implies the distance where the potential is 1 MV.
Since the electric potential of a point charge is as follows:
V = kQ / r
Therefore, we can solve for r and estimate it as follows:
R = kQ / V = (9 * 10^9 * 5 * 10^(-3)) / 1 * 10^6 = 45 m
Therefore, the distance from which its center is the potential 1.00 MV is 45 m.
(c) An oxygen atom with three missing electrons is released near the Van de Graaff generator. What is its energy in MeV when the atom is at the distance found in part b?
The link between the potential difference and electrical potential energy can be stated as follows:
ΔV = ΔU / q
Therefore, we have:
ΔU = qΔV = q(Va - Vb) = 3 * (45 – 1) = 132 MeV
Therefore, its energy in MeV when the atom is at the distance found in part b is 132 MeV.
What salt will be produced by the neutralization reaction between hydrochloric acid (HCI) and
the base calcium hydroxide (Ca(OH)2)? Which part of the salt produced will be the conjugate
base of the acid, and which will be the conjugate acid of the base? Write the balanced
equation.
Please help due todayyyy!?!
Answer:
The produced salt is calcium chloride, CaCl₂, whose cation, Ca²⁺, is the conjugate acid of the base and the anion, Cl⁻ the conjugate base of the acid.
Explanation:
Hello there!
In this case, according to the given information, it turns out firstly necessary for us to set up the chemical equation between calcium hydroxide and hydrochloric acid:
[tex]2HCl+Ca(OH)_2\rightarrow CaCl_2+2H_2O[/tex]
It means that the produced salt is calcium chloride, CaCl₂, whose cation, Ca²⁺, is the conjugate acid of the base and the anion, Cl⁻ the conjugate base of the acid.
Regard"
For an ideal gas, classify the pairs of properties as directly or inversely proportional. You are currently in a sorting module. a. P and n b. V and n c. P and T d. T and V e. P and V1. directly proportional2. inversely proportional
Answer:
the result for the following are (a) P is directly proportional to n
(b) V is directly proportional to T (c) P is directly proportional to T (d) T is inversly proportional to V (e) P is inversely proportional to V
Senario: 2 years ago, a fruit was smuggled into California on a plane from an exotic, far away land. The homeowner saw that the fruit had maggots and tossed it into the backyard, hoping the seed would grow. The larvae hatched out and moved throughout the area. This fictitious insect will destroy fruit and has the possibility of spreading disease killing the trees. The insect consumes plants in the Prunus species of stone fruits? Look up the plant genus Prunus.
Discussion: The insect has spread over a large area of Southern California, discovered at UC Riverside. What steps would you do to control or eradicate the destructive exotic insect?
PLZ HELP THX WITH COLLEGE LEVEL EXPERICENCE
Answer:
The best existing methods of control—artemisinin-based drug treatment and insect control with chemical sprays and treated bednets—can reduce the burden of disease substantially, and can even eliminate the disease in some regions,
hope this will help you more
13. A mixture of MgCO3 and MgCO3.3H2O has a mass of 3.883 g. After heating to drive off all the water the mass is 2.927 g. What is the mass percent of
Answer:
63.05% of MgCO3.3H2O by mass
Explanation:
of MgCO3.3H2O in the mixture?
The difference in masses after heating the mixture = Mass of water. With the mass of water we can find its moles and the moles and mass of MgCO3.3H2O to find the mass percent as follows:
Mass water:
3.883g - 2.927g = 0.956g water
Moles water -18.01g/mol-
0.956g water * (1mol/18.01g) = 0.05308 moles H2O.
Moles MgCO3.3H2O:
0.05308 moles H2O * (1mol MgCO3.3H2O / 3mol H2O) =
0.01769 moles MgCO3.3H2O
Mass MgCO3.3H2O -Molar mass: 138.3597g/mol-
0.01769 moles MgCO3.3H2O * (138.3597g/mol) = 2.448g MgCO3.3H2O
Mass percent:
2.448g MgCO3.3H2O / 3.883g Mixture * 100 =
63.05% of MgCO3.3H2O by massWhat is the percent yield of the reaction below if 84.0 grams of Al2O3(s) is recovered from a reaction whose theoretical yield of Al2O3(s) is 104 grams?
4 Al(s) + 3 O2(g) → 2 Al2O3(s)
Answer:
80.8%
Explanation:
Let's consider the following balanced equation.
4 Al(s) + 3 O₂(g) → 2 Al₂O₃(s)
The mass obtained of Al₂O₃ (experimental yield) is 84.0 g. The theoretical yield of Al₂O₃ is 104 g. We can calculate the percent yield of Al₂O₃ using the following expression.
%yield = (experimental yield / theoretical yield) × 100%
%yield = (84.0 g / 104 g) × 100% = 80.8%
Answer:
Percent Yield = 80.8%
Explanation:
We can find the percent yield of a reaction using the equation:
Percent yield = Actual yield (g) / Theoretical Yield (g) * 100
Where Actual yield is the amount of product produced (84.0g)
And theoretical yield is the mass produced assuming a 100% of product (104.0g)
Replacing the computed values:
Percent yield = 84.0g / 104.0g * 100
Percent Yield = 80.8%
Match the description with the type of precipitation being described.
1. Its formation requires very strong updrafts
2. Its formation requires falling through a layer of above freezing air
3. Precipitation from cumuliform clouds is typically of this nature
4. Precipitation from stratus clouds is typically of this nature
Options:
a. Hail
b. Drizzle
c. Shower
d. Freezing Rain
Answer:
1. Its formation requires very strong updrafts = a. Hail
2. Its formation requires falling through a layer of above-freezing air = d. Freezing Rain
3. Precipitation from cumuliform clouds is typically of this nature = c. Shower
4. Precipitation from stratus clouds is typically of this nature = Drizzle
Explanation:
Hail formation requires very strong updrafts, these updrafts are the upward moving air created in a thunderstorm. This period of noticeable thunderstorms creates hails.
Freezing rain requires the presence of warm air, it requires falling through a layer of above-freezing air to the colder air below to produce an ice coating on anything it drops on.
Showers are produced by cumuliform clouds which look like cotton balls. Since cumuliform clouds precipitate too, these clouds can have fluctuating rain in a day in the form of showers.
Drizzle which raises low visibility is considered a type of liquid precipitation since it also falls from a cloud. Drizzle which is obviously smaller in diameter when compared to that of raindrops, however, is common with stratus clouds.
Aqueous hydrobromic acid (HBr) will react with solid sodium hydroxide (NaOH) to produce aqueous sodium bromide (NaBr) and liquid water (H2O). Suppose 5.7 g of hydrobromic acid is mixed with 0.980 g of sodium hydroxide. Calculate the maximum mass of water that could be produced by the chemical reaction. Round your answer to significant digits.
Answer:
The maximum mass of water that could be produced by the chemical reaction=0.441g
Explanation:
We are given that
Given mass of HBr=5.7 g
Given mass of sodium hydroxide=0.980 g
Molar mass of HBr=80.9 g/ Mole
Molar mass of NaOH=40 g/mole
Molar mass of H2O=18 g/mole
Reaction
[tex]HBr+NaOH\rightarrow H_2O+NaBr[/tex]
Number of moles=[tex]\frac{given\;mass}{molar\;mass}[/tex]
Using the formula
Number of moles of HBr=[tex]\frac{5.7}{80.9}=0.0705 moles[/tex]
Number of moles of NaOH=[tex]\frac{0.980}{40}=0.0245moles[/tex]
Hydrogen bromide is in a great excess and the amount of water produced.
Therefore,
Number of moles of water, n(H2O)=Number of moles of NaOH=0.0245moles
Now,
Mass of water=[tex]n(H_2O)\times Molar\;mass\;of\;water[/tex]
Mass of water=[tex]0.0245moles\times 18=0.441g[/tex]
Hence, the maximum mass of water that could be produced by the chemical reaction=0.441g
A chemist measures the amount of iodine solid produced during an experiment. He finds that of iodine solid is produced. Calculate the number of moles of iodine solid produced. Round your answer to significant digits.
The question is incomplete, the complete question is:
A chemist measures the amount of iodine solid produced during an experiment. He finds that 8.31 g of iodine solid is produced. Calculate the number of moles of iodine solid produced. Round your answer to the correct number of significant digits.
Answer: The number of moles of solid iodine produced is 0.0327 moles
Explanation:
The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)
Given mass of solid iodine = 8.31 g
Molar mass of solid iodine = 253.8089 g/mol
Plugging values in equation 1:
[tex]\text{Moles of solid iodine}=\frac{8.31g}{253.8089g/mol}=0.0327mol[/tex]
Hence, the number of moles of solid iodine produced is 0.0327 moles
Which of the following was NOT explained by Dalton's atomic theory?
ANSWER:
A. the Law of Multiple Proportions
B. the difference between elements and compounds
C.?the difference between isotopes of an element
D. the Law of Conservation of Mass
Answer:
A. the Law of Multiple Properties
Answer:
A. the law of multiple proportions
If a hydrogen atom and a helium atom have the same kinetic energy:________
a. the wavelength of the hydrogen atom will be about 4 times longer than the wavelength of the helium atom.
b. the wavelength of the hydrogen atom will be about 2 times longer than the wavelength of the helium.
c. the wavelength of the hydrogen atom will be roughly equal to the wavelength of the helium atom.
d. the wavelength of the helium atom will be about 2 times longer than the wavelength of the hydrogen atom.
e. the wavelength of the helium atom will be about 4 times longer than the wavelength of the hydrogen atom.
Answer: If a hydrogen atom and a helium atom have the same kinetic energy then the wavelength of the hydrogen atom will be roughly equal to the wavelength of the helium atom.
Explanation:
The relation between energy and wavelength is as follows.
[tex]E = \frac{hc}{\lambda}\\[/tex]
This means that energy is inversely proportional to wavelength.
As it is given that energy of a hydrogen atom and a helium atom is same.
Let us assume that [tex]E_{hydrogen} = E_{helium} = E'[/tex]. Hence, relation between their wavelengths will be calculated as follows.
[tex]E_{hydrogen} = \frac{hc}{\lambda_{hydrogen}}[/tex] ... (1)
[tex]E_{helium} = \frac{hc}{\lambda_{helium}}[/tex] ... (2)
Equating the equations (1) and (2) as follows.
[tex]E_{hydrogen} = E_{helium} = E'\\\frac{hc}{\lambda_{hydrogen}} = \frac{hc}{\lambda_{helium}} = E'\\\lambda_{helium} = \lambda_{hydrogen} = E'[/tex]
Thus, we can conclude that if a hydrogen atom and a helium atom have the same kinetic energy then the wavelength of the hydrogen atom will be roughly equal to the wavelength of the helium atom.
explain why the melting point of a solid is equal to the freezing point of it's liquid.
Explanation:
Because melting point and freezing point describe the same transition of matter, in this case from liquid to solid (freezing) or equivalently, from solid to liquid (melting). It is stuck on 0 ∘C during the entire melting or freezing process. None except melting is when you heat up and freezing when you cool down.hope it helps.stay safe healthy and happy.Calculate the solubility (in mol/L) of Fe(OH)3 (Ksp = 4.0 x 10^-38) in each of the following situations:
(A) Pure water (assume that the pH is 7.0 and remains constant).
(B) A solution buffered at pH = 5.0.
(C) A solution buffered at pH = 11.0.
Answer:
(A) 1.962x10^-10 M solubility in pure water
(B) 4.0 x 10^-33 M solubility
(C) 4.0 x 10^-27 M solubility
Explanation:
(A) Fe(OH)3 would give (Fe3+) and (3OH-)
Ksp = [Fe^3+][OH-]^3 = 4.0 x 10^-38
Let y = [Fe^3+]
Let 3y = [OH-]
4x10^-38 = (y)(3y)^3
4x10^-38 = 27y^4
y^4 = 4x10^-38 ÷ 27
y^4 = 1.481 x 10^-39
y = 1.962x10^-10 M solubility in pure water
(B) pH = 5.0
5.0 = - log [OH-]
-5.0 = log [OH-]
[OH-] = 10^-5.0 = 1.0 x 10^-5 M
So, Ksp = [Fe^3+][OH-]^3 = 4.0 x 10^-38
[Fe^3+][1.0 x 10^-5] = 4.0 x 10^-38
[Fe^3+] = 4.0 x 10^-38 ÷ 1.0 x 10^-5
= 4.0 x 10^-33 M solubility
(C) pH = 11.0
11.0 = - log [OH-]
-11.0 = log [OH-]
[OH-] = 10^-11.0 = 1.0 x 10^-11 M
So, Ksp = [Fe^3+][OH-]^3 = 4.0 x 10^-38
[Fe^3+][1.0 x 10^-11] = 4.0 x 10^-38
[Fe^3+] = 4.0 x 10^-38 ÷ 1.0 x 10^-11
= 4.0 x 10^-27 M solubility
define saturated and unsaturated fats
Answer:
unsaturated fats, which are liquid at room temperature,are different from saturated fat because they contain one or more double bonds and fewer hydrogen atoms on their carbon chain.
An ice freezer behind a restaurant has a freon leak, releasing 47.97 g of C2H2F3Cl into the air every week. If the leak is not fixed, how many kilograms of fluorine will be released into the air over 6 months
Answer:
0.554 kg
Explanation:
We want to find the amount of kilograms of fluorine that will be released into the air over 6 months.
Let's convert to weeks to get;
6 × 4 = 24 weeks
Let's find Mass leak rate of fluorine from the formula;
Mass leak rate = (fluorine mass in freon/molar mass of freon) × leak rate
Molar mass of freon = ((12 × 2) + (1 × 2) + (19 × 3) + (35.5)) = 118.5 g/mol
Thus;
Mass leak rate = ((19 × 3)/(118.5)) × 47.97 = 23.074 g/week
Total fluorine leaked in 6 months = 24 × 23.074 = 553.776 g = 0.554 kg
A. Consider the following neutral electron configurations in which n has a constant value. Which configuration would belong to the element with the most negative electron affinity, Eea?
1. 2s2
2. 2s2 2p2
3. 2s2 2p5
4. 2s2 2p6
B. Arrange the following elements from greatest to least tendency to accept an electron.
Rank from greatest to least tendency to accept an electron. To rank items as equivalent, overlap them.
1. Sr
2. Sn
3. Rb
4. Te
5. I
Answer:
2s2 2p5
Rb < Sr< Sn< Te<I
Explanation:
Electron affinity is the ability of an atom to accept electrons to form negative ions.
Electron affinity is a periodic trend that decreases down the group but increases across the period.
This accounts for the trends observed in the answer. The atom having the electronic configuration, 2s2 2p5 must be a halogen and it exhibits the highest value of electron affinity.
Also, since electron affinity increases across the period, the electron affinities of the elements increases. Therefore, the arrangement of atoms as shown in the answer depends on increasing electron affinity.
For each of the following circumstances, indicate whether the calculated molarity of NaOH would be lower, higher or unaffected. Explain your answer in each case. a. The inside of the pipet used to transfer the standard HCl solution was wet with water.b. you added 40 mL of water to the titration flask rather than 25ml. c. The buret, wet with water, was not rinsed with NaOH solution before filling the buret with NaOH solution. d. Five (5) drops of phenolphthalein were added to the solution to be titrated rather than three (3) drops.
Answer:
a)calculated molarity of NaOH would be lower
b) calculated molarity of NaOH would be lower
c) calculated molarity of NaOH would be lower
d) calculated molarity of NaOH would be unaffected
Explanation:
Let us recall that the reaction of NaOH and HCl is as follows;
NaOH(aq) + HCl(aq) ----> NaCl(aq) + H2O(l)
Since the reaction is 1:1, when the number of moles of HCl reacting with NaOH is low due to dilution, the calculated molarity of NaOH also becomes less than it's accurate value.
When 40mL of water is added to the titration flask rather than 25ml of water, the acid is more dilute hence less number of moles of acid than necessary reacts with the base thereby yielding a less than accurate value of the molarity of NaOH.
If the burette wet with water is not rinsed with NaOH solution, the concentration of the NaOH in the burette decreases due to dilution with water and a less than accuracy value is calculated for the molarity of NaOH.
If five drops of phenolphthalein is used instead of one or two drops, there is no qualms since enough phenolphthalein may be added to ensure that a sharp end point is obtained.
