The color change exhibited by phenolphthalein during a titration of aqueous acetic acid with aqueous sodium hydroxide is pink to colorless.
An indicator is an organic dye which changes color in acidic, basic and neutral medium.
Phenolphthalein is an example of an indicator. When aqueous acetic acid is titrated against aqueous sodium hydroxide, the indicator may be added to the basic solution.
Phenolphthalein has a pink color in a basic medium. As the acid is added gradually, the solution turns colorless at end point.
Hence, the color change exhibited by phenolphthalein during a titration of aqueous acetic acid with aqueous sodium hydroxide is pink to colorless.
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Calculate the percentage difference in the fundamental vibrational wavenumbers of 23Na35Cl and 23Na37Cl on the assumption that their force constants are the same. The mass of 23Na is 22.9898mu.
Answer:
1.089%
Explanation:
From;
ν =1/2πc(k/meff)^1/2
Where;
ν = wave number
meff = reduced mass or effective mass
k = force constant
c= speed of light
Let
ν =1/2πc (k/meff)^1/2 vibrational wave number for 23Na35 Cl
ν' =1/2πc(k'/m'eff)^1/2 vibrational wave number for 23Na37 Cl
The between the two is obtained from;
ν' - ν /ν = (k'/m'eff)^1/2 - (k/meff)^1/2 / (k/meff)^1/2
Therefore;
ν' - ν /ν = [meff/m'eff]^1/2 - 1
Substituting values, we have;
ν' - ν /ν = [(22.9898 * 34.9688/22.9898 + 34.9688) * (22.9898 + 36.9651/22.9898 * 36.9651)]^1/2 -1
ν' - ν /ν = -0.01089
percentage difference in the fundamental vibrational wavenumbers of 23Na35Cl and 23Na37Cl;
ν' - ν /ν * 100
|(-0.01089)| × 100 = 1.089%
Answer:
1.089%
Explanation:
From;
ν =1/2πc(k/meff)^1/2
Where;
ν = wave number
meff = reduced mass or effective mass
k = force constant
c= speed of light
Let
ν =1/2πc (k/meff)^1/2 vibrational wave number for 23Na35 Cl
ν' =1/2πc(k'/m'eff)^1/2 vibrational wave number for 23Na37 Cl
The between the two is obtained from;
ν' - ν /ν = (k'/m'eff)^1/2 - (k/meff)^1/2 / (k/meff)^1/2
Therefore;
ν' - ν /ν = [meff/m'eff]^1/2 - 1
Substituting values, we have;
ν' - ν /ν = [(22.9898 * 34.9688/22.9898 + 34.9688) * (22.9898 + 36.9651/22.9898 * 36.9651)]^1/2 -1
ν' - ν /ν = -0.01089
percentage difference in the fundamental vibrational wavenumbers of 23Na35Cl and 23Na37Cl;
ν' - ν /ν * 100
|(-0.01089)| × 100 = 1.089%
How many molecules are present in 4.21 moles of HBr?
Answer:
The answer is
2.53 × 10²⁴ moleculesExplanation:
The number of molecules present can be found by using the formula
N = n × Lwhere n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
N = 4.21 × 6.02 × 10²³
We have the final answer as
2.53 × 10²⁴ moleculesHope this helps you
PLease help me I am giving a lot of points for this please help me
Answer:
Under balanced its motion under motion its s = d/t under s - d/t is time d = distance s= speed
Explanation:
During the formation of water from hydrogen atoms and one oxygen
Answer:
B
Explanation:
hydrogen only has one electron/molecule in it's only shell so it can get together and make a bond
Given the reaction _K(s) +_ Cl2(g) → _KCl(s) what is the amount of K, in grams, needed to completely react with 2 moles of Cl2(g)?
Answer:
156.4g K
Explanation:
I'm not sure if it is correct but I think it should be this
What do we know so far?: 2K + 1Cl2 -> 2KCl, 2 mol of Cl2
What are we looking for?: #g of K
What is the ratio of K to Cl2?: 2:1
Set up equation: 2molCl2 x [tex]\frac{2mol K}{1 mol Cl2}[/tex]
Cancel unwanted units: 2 x [tex]\frac{2mol K}{1}[/tex]
Answer we got: 2 x 2mol K = 4mol K
Converting moles to grams: 4 x 39.1 (molar mass of K) = 156.4g K
is the center of an atom is called the nucleus?
Answer:
The center of the atom contains the nucleus so yes
Explanation:
For the following reaction at equilibrium SO3(g) + NO(g) = SO2(g) + NO2(g)It is found that [SO2] = 0.70 M and [NO] = 1.20 M. Calculate the equilibrium constant for the readction knowing that the initial concentration were [SO3] = 2.55 M and [NO] = 1.90 M.
Answer:
[tex]K=0.14[/tex]
Explanation:
Hello!
In this case, for the undergoing chemical reaction, we can write the equilibrium expression via:
[tex]K=\frac{[SO_2][NO_2]}{[SO_3][NO]}[/tex]
Whereas the equilibrium concentration of both SO3 and NO are 2.55 M and 1.90 M respectively, it means that the extent of reaction [tex]x[/tex] is:
[tex]x=1.90M-1.20M=0.7M[/tex]
Because the equilibrium expression in terms of the reaction extent is:
[tex]K=\frac{x*x}{([SO_3]_0-x)([NO]_0-x)}[/tex]
It means that the concentration of SO3, NO, SO2 and NO2 at equilibrium are:
[tex][SO_3]=2.55M-0.70M=1.85M[/tex]
[tex][NO]=1.20M[/tex]
[tex][SO_2]=0.70M[/tex]
[tex][NO_2]=0.70M[/tex]
Thus, the equilibrium constant for such reaction is:
[tex]K=\frac{0.70*0.70}{1.85*1.90}\\\\K=0.14[/tex]
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A gram sample of a KCl and KClO3 mixture was found to contain 0.00875 mol of KClO3. What is the percent by mass of KClO3 in the original mixture?
Answer:
53.5%
Explanation:
Step 1: Given data
Mass of the sample: we will suppose it is 2.00 g to show the procedureMoles of KClO₃: 0.00875 molStep 2: Calculate the mass corresponding to 0.00875 moles of KClO₃
The molar mass of KClO₃ is 122.55 g/mol.
0.00875 mol × 122.55 g/mol. = 1.07 g
Step 3: Calculate the percent by mass of KClO₃ in the mixture
We will use the following expression.
%m/m = mass of KClO₃/mass of the sample × 100%
%m/m = 1.07 g/2.00 g × 100%
%m/m = 53.5%
The percent by mass of KClO3 in the original mixture is 53.5%.
Calculation of the percentage:Since
The mass of the sample should be 2.00 g
Moles of KClO₃: 0.00875 mol
The molar mass of KClO₃ is 122.55 g/mol.
Now the mass is
= 0.00875 mol × 122.55 g/mol.
= 1.07 g
Now the percentage should be
= mass of KClO₃/mass of the sample × 100%
= 1.07 g/2.00 g × 100%
= 53.5%
hence, The percent by mass of KClO3 in the original mixture is 53.5%.
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Calculate the Molarity when a 6.11 mL solution of 0.1 H2SO4 is diluted with 105.12 mL of water
Molarity after dilution : 0.0058 M
Further explanationThe number of moles before and after dilution is the same
The dilution formula
M₁V₁=M₂V₂
M₁ = Molarity of the solution before dilution
V₁ = volume of the solution before dilution
M₂ = Molarity of the solution after dilution
V₂ = Molarity volume of the solution after dilution
M₁=0.1 M
V₁=6.11
V₂=105.12
[tex]\tt M_2=\dfrac{M_1.V_1}{V_2}=\dfrac{0.1\times 6.11}{105.12}=0.0058~M[/tex]
An example of a suspension is a ____
A)chemical b)heterogenous
c)homogenous d)salad
Answer:
b
Explanation:
suspension is the heterogenos solution
Which of the following are fair conductors and are always solid at room temperature?
1.Metals
2.Nonmetals
3.Metalloids
4.Ions
Answer:
Metalloids and ions
Explanation:
Mercury is not solid at room temperature. (Metals)
Many nonmetals aren't good at conducting electricity. Oxygen for example. (Nonmetals)
Metalloids are always solid at room temp and are fair conductors. (Metalloids)
Ions are same as metalloids. (Ions)
PLS GIVE BRAINLIEST
Which one is NOT true about chemical changes? *
Answer:
The second answer
Explanation:
Phase changes is an example of physical change because it only changes the substance's appearance.
Answer: 1 and 4 are the answers
Explanation: because when you mix a sub since and it will have a chemical change
Calculate the volume in milliliters of 1.57 M potassium hydroxide that contains 10.3 g of solute.
Answer:
[tex]V = 0.117 \ L[/tex]
General Formulas and Concepts:
Chem
Reading a Periodic TableWriting compounds and polyatomic ionsMolarity = moles of solute / liters of solutionExplanation:
Step 1: Define
1.57 M KOH (potassium hydroxide)
10.3 g KOH
Step 2: Define conversions
Molar Mass of K - 39.10 g/mol
Molar Mass of O - 16.00 g/mol
Molar Mass of H - 1.01 g/mol
Molar Mass of KOH - 39.10 + 16.00 + 1.01 = 56.11 g/mol
Step 3: Convert
[tex]10.3 \ g \ KOH(\frac{1 \ mol \ KOH}{56.11 \ g \ KOH} )[/tex] = 0.183568 mol KOH
Step 4: Solve for Volume
Substitute: [tex]1.57 \ M=\frac{0.183568 \ mol}{x \ L}[/tex]Move x: [tex]x1.57 \ M=0.183568 \ mol[/tex]Isolate x: [tex]x=\frac{0.183568 \ mol}{1.57 \ M}[/tex]Evaluate: [tex]x=0.116922 \ L[/tex]Step 5: Check
We are given 3 sig figs. Follow sig fig rules.
[tex]0.116922 \ L \approx 0.117 \ L[/tex]
Whats the answer 50 points and brainliest if its right
Answer:
D
Explanation:
Which element would most likely have a chemical reactivity similar to bromine?
Answer:
Bromine is a very reactive element. While it is less reactive than fluorine or chlorine, it is more reactive than iodine. It reacts with many metals, sometimes very vigorously. For instance, with potassium, it reacts explosively.
Explanation:
Answer: Bromine is a high reactive element. While it is not as reactive as fluorine or chlorine, it is still more reactive than iodine. It reacts with many metals, and even sometimes very aggressively. For example, when mixed with potassium, it will explode.
Explanation:
The ingredients of a soup include
1,500 grams of water, 350 grams of vegetables, and 210 grams of meat. What is the total mass of the soup?
Answer:
sopas
Explanation:
lagyan mo ng condense
There is a golden role of solubility, polar solute dissolve in polar solvent and non polar solute dissolve in non polar solvent. Therefore, the total mass of the soup is 2,060gram.
What is solution?Solutions are a homogeneous mixture of two or more substances. A solution is a homogeneous mixture of solvent and solute molecules. Solvent is a substance that is in large amount in solution. solute is the substance which is in small amount in a solution. There are two types of mixture that is homogeneous and heterogeneous. Solution is a homogeneous solution.
mass of soup= mass of water+ mass of vegetables + mass of meat
mass of water=1,500 grams
mass of vegetables= 350 grams
mass of meat=210 grams
substituting all the values in the above equation, we get
mass of soup= 1,500 grams+ 350 grams + 210 grams
= 2,060gram
Therefore, the total mass of the soup is 2,060gram.
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Choose ALL the answers that apply.
Sound _____.
travels in transverse waves
requires a medium to travel through
travels most slowly through solids
speeds up when temperature is increased
is changed into electrical impulses by the cochlea
Answer:
Speeds up when temperature is increased and can travel through a solid
Explanation:
1Water molecules can be ligands especially when they are bonded to
..........
A. alkaline earth metals
B. alkali metals
C. transition metals
D. group VII elements
Answer:c
Explanation:
why did Aristotle disagree with Democritus
Answer: He theorized that all material bodies are made up of indivisibly small “atoms.” Aristotle famously rejected atomism in On Generation and Corruption. Aristotle refused to believe that the whole of reality is reducible to a system of atoms.
Explanation:
Aristotle disagreed with Democritus primarily on the nature of matter and the concept of atomism.
Democritus proposed the theory of atomism, suggesting that all matter is composed of indivisible and indestructible particles called atoms. He believed that atoms combine and interact to form different substances.
On the other hand, Aristotle rejected the notion of atomism and instead proposed a different theory of matter. According to Aristotle, matter is continuous and infinitely divisible. He believed that substances are composed of four primary elements - earth, air, fire, and water - which have different inherent properties and undergo transformations through the combination and separation of these elements.
Aristotle's disagreement with Democritus stemmed from their differing views on the fundamental nature of matter. While Democritus emphasized the discrete and fundamental nature of atoms, Aristotle emphasized the continuous and composite nature of matter. Their contrasting viewpoints reflected a broader philosophical divide between atomism and holism in ancient Greek philosophy.
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Draw conclusion: The density of water is 1.0 g/mL, or 1.0 g/cm². Look at the data in your table. How can you use the density of an object to predict whether it will sink or float?
(Data is above)
PLEASE HELP
Answer:
work out if it's either going to sink or float
Explanation:
this can be carried out by calculating the numbers
A buffer is prepared by mixing 204.0 mL of 0.452 M HCl and 0.500 L of 0.400 M sodium acetate (NaC2H3O2):
Calculate the pH of the buffer.
How many grams of KOH must be added to 0.500 L of the buffer to change the pH by 0.15 units?
Answer:
pH = 4.89
0.6171g of KOH must be added
Explanation:
Sodium acetate reacts with HCl producing acetic acid as follows:
NaC2H3O2 + HCl → HC2H3O2 + NaCl
That means the moles added of HCl are moles of acetic acid produced and moles of acetate are initial moles - moles of HCl
Moles HCl = Moles acetic acid:
0.204L * (0.452mol / L) = 0.0822 moles acetic acid.
Initial moles sodium acetate:
0.500L * (0.400mol / L) = 0.200 moles
Moles sodium acetate:
0.200 moles - 0.0822 moles = 0.1172 moles sodium acetate
The pH of this buffer (Mixture of a weak acid and its conjugate base) is obtained using H-H equation:
pH = pKa + log [A-] / [HA]
Where pH is pH of the buffer,
pKa is pKa of the buffer (4.74 for acetic acid)
[A-] Moles of sodium acetate -Conjugate base-
And HA moles of acetic acid -Weak acid-
pH = 4.74 + log [0.1172 moles] [0.0822 moles]
pH = 4.89In 0.500L the moles of the buffer are:
0.500L * (0.200moles / 0.704L) = 0.142 moles of buffer
For a pH of 0.15 units more (4.89 + 0.15 = 5.04):
5.04 = 4.74 + log [Acetate] / [Acetic acid]
0.3 = log [Acetate] / [Acetic acid]
1.9953 = [Acetate] / [Acetic acid] (1)
And as:
0.142 = [Acetate] + [Acetic acid] (2)
Replacing (2) in (1):
1.9953 = 0.142 - [Acetic acid] / [Acetic acid]
1.9953 [Acetic acid] = 0.142 - [Acetic acid]
2.9953 [Acetic acid] = 0.142 moles
[Acetic acid] = 0.0474 moles of acetic acid must remain after the addition of KOH.
In the beginning, moles of acetic acid are:
0.0822 moles * (0.500L / 0.704L) = 0.0584 moles.
That means moles added of KOH (Equal to moles of acetic acid that react) are:
0.0584 moles - 0.0474 moles = 0.0110 moles of KOH
In grams (Molar mass KOH = 56.1g/mol):
0.0110 moles KOH * (56.1g/mol) =
0.6171g of KOH must be addedA microwave operates at 7.42 mm wavelength. How much energy is produced in Joules from 359 photons?
answer numerically using scientific notation with e and significant figures.
Answer:
[tex]E=9.62\times 10^{-21}\ J[/tex]
Explanation:
Given that,
The wavelength of a microwave is 7.42 mm or 0.00742 m
No. of photons, n = 359
We need to find the energy produced by this no of photons. It can be given by the formula as follows :
[tex]E=\dfrac{nhc}{\lambda}\\\\E=\dfrac{359\times 6.63\times 10^{-34}\times 3\times 10^8}{0.00742}\\\\=9.62\times 10^{-21}\ J[/tex]
or
[tex]E=9.62e^{-21}\ J[/tex]
So, the required energy is [tex]9.62\times 10^{-21}\ J[/tex].
Answer:
⬆️That guy deserves brainliest
Explanation:
PLZ HELP ASAP
Which would increase the reaction rate?
Check all that apply.
A. Stirring the reaction
B. Raising the activation energy
O C. Adding a catalyst
D. Raising the temperature
Answer:
adding a catalyst will increase the reaction rate.
Explanation:
im like 95% sure thats right.
Answer:
A. C. D
Explanation:
ap ex
find examples for each polysaccharides type.
Answer:
Glycogen: It is made up of a large chain of molecules. ...
Cellulose: The cell wall of the plants is made up of cellulose. ...
Starch: It is formed by the condensation of amylose and amylopectin. ...
Insulin: It is made up of a number of fructofuranose molecules linked together in chains.
Explanation:
In ethane, C2H6, ethene (ethylene), C2H4, and ethine (acetylene), C2H2, there are direct carbon-carbon bonds. Which one is the shortest?
a. The carbon-carbon bond in ethane's the longest!)
b. The carbon-carbon bond in ethene is the longest
c. The carbon-carbon bond in ethyne is the longest.
d. All of the carbon-carbon bonds have the same length.
Answer:
a. The carbon-carbon bond in ethane's the longest!)
Explanation:
Ethane is a chemical compound that is organic in nature. Its chemical formula is [tex]$C_2H_6$[/tex]. It has two carbon atoms and six of hydrogen atoms that is connected to the carbon atoms.
Ethane is odorless and colorless at the standard temperature and standard pressure.
The carbon to carbon atoms in ethane is connected by a single bond.
The length of single carbon-carbon bond is greater than carbon-carbon double bond and triple bond.
Thus, carbon-carbon bond length in ethane is the longest.
What is the hybridization state on the central N atom in the azide ion, N3−?
The noble gases can be found in group/period ____
Answer:
group 18
Explanation:
The noble gases (Group 18) are located in the far right of the periodic table and were previously referred to as the "inert gases" due to the fact that their filled valence shells (octets) make them extremely nonreactive
Answer:group 18
Explanation
Arrange in order of decreasing atomic radii: Kr, K, Ge, Ca
Answer:
K > Ca > Ge > Kr
Explanation:
The elements given are all in the 4th period on the periodic table.
Kr, k, Ge, Ca;
Arranging their order from left to right;
K, Ca, Ge, Kr
Atomic radius is taken as half the of the inter-nuclear distance (d) between two covalently bonded atoms of non-metallic elements or half the distance between two nuclei in the solid state of metals.
Across the periodic table atomic radii decreases progressively from left to right. This is due to progressive increase in the nuclear charge (number of protons in the nucleus) without an attendant increase in the number of electronic shells.
From the left to right; decreasing radii;
K > Ca > Ge > Kr
What creates a weather front?
A weather front is a transition zone between two different air masses at the Earth's surface. Each air mass has unique temperature and humidity characteristics. Often there is turbulence at a front, which is the borderline where two different air masses come together. The turbulence can cause clouds and storms.
Molarity to percent by mass. Convert 1.672 mol/L MgCl2(aq) solution to percent by mass of MgCl2 in the solution. The solution density at this concentration is 1.137 g/mL. Answer to 4 significant figures with appropriate units.
Answer:
[tex]\%m/m=14\%[/tex]
Explanation:
Hello!
In this case, since the molarity of magnesium chloride (molar mass = 95.211 g/mol) is 1.672 mol/L and we know the density of the solution, we can first compute the concentration in g/L as shown below:
[tex][MgCl_2]=1.672\frac{molMgCl_2}{L}*\frac{95.211gMgCl_2}{1molMgCl_2}=159.2\frac{gMgCl_2}{L}[/tex]
Next, since the density of the solution is 1.137 g/mL, we can compute the concentration in g/g as shown below:
[tex][MgCl_2]=159.2\frac{gMgCl_2}{L}*\frac{1L}{1000mL}*\frac{1mL}{1.137g}=0.14[/tex]
Which is also the by-mass fraction and in percent it turns out:
[tex]\%m/m=0.14*100\%\\\\\%m/m=14\%[/tex]
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