We are 99% confident that the true population variance (σ2) is between 93.3058 and infinity.
To construct a 99% confidence interval for σ2 in exercise 9.11 on page 303, we first need to calculate the sample variance, denoted by s2. This exercise doesn't provide us with any data, so let's assume we have a sample of size n = 20 and the following observations:
6, 8, 9, 10, 12, 13, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 30
Using a calculator or software, we can find that the sample variance is s2 = 43.8842.
Next, we need to determine the degrees of freedom for the chi-square distribution. Since we have n = 20 observations, we have (n-1) = 19 degrees of freedom.
The formula for the confidence interval for σ2 is:
[ (n-1) s2 / χ2α/2, (n-1) s2 / χ2(1-α/2) ]
where α is the level of significance (1 - confidence level) and χ2α/2 and χ2(1-α/2) are the values from the chi-square distribution with α/2 and 1-α/2 degrees of freedom, respectively.
For a 99% confidence level, α = 0.01, so α/2 = 0.005. Using a chi-square distribution table or calculator, we can find that χ2α/2 = 8.9076 and χ2(1-α/2) = 32.8523.
Substituting these values into the formula, we get:
[ 19(43.8842) / 8.9076, 19(43.8842) / 32.8523 ]
Simplifying, we get:
[ 93.3058, 12.5245 ]
Since the lower bound of the confidence interval is negative, we need to adjust it to zero, since variances can't be negative. Thus, our final 99% confidence interval for σ2 is:
[ 93.3058, 12.5245 ] --> [ 93.3058, ∞ )
Therefore, we are 99% confident that the true population variance (σ2) is between 93.3058 and infinity.
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To construct a 99% confidence interval for σ2 in exercise 9.11 on page 303, we need to use the chi-square distribution. The population variance is unknown, but we have a random sample of n = 20 measurements and we know that the sample variance is s2 = 16.3.
From the chi-square distribution table with 19 degrees of freedom (n-1), we find the values of chi-square that correspond to the upper and lower 0.5% tail probabilities, which are 36.191 and 8.907, respectively. We then calculate the confidence interval for σ2 using the formula:
((n-1)*s2)/chi-square_upper, ((n-1)*s2)/chi-square_lower
Substituting the values, we get:
((20-1)*16.3)/36.191 = 10.87
((20-1)*16.3)/8.907 = 31.39
Therefore, the 99% confidence interval for σ2 is (10.87, 31.39). This means that we are 99% confident that the population variance falls between these two values.
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Will mark you brainliest and give you 15 points!!
what is the mass of 22.4 l of n2 at stp? (5 points)
a
11.2 grams
b
14.00 grams
c
22.4 grams
d
28.01 grams
Answer:
d
Explanation:
22.4 L is the same as 1 mol.
Diatomic nitrogen has a formula mass of 28.01 g/mol, so the answer is d.
Show the calculations to determine the volume of the 0.1 M buffer from Part A needed to make 100 mL of a 0.01 M buffer.
The volume of the 0.1 M buffer from Part A needed to make 100 mL of a 0.01 M buffer is 10mL.
How to calculate volume?The volume of a substance can be calculated using the following formula;
C1V1 = C2V2
Where;
C1 = initial concentrationC2 = final concentrationV1 = initial volumeV2 = final volume0.1 × V1 = 100 × 0.01
0.1V1 = 1
V1 = 1/0.1
V1 = 10mL
Therefore, the volume of the 0.1 M buffer from Part A needed to make 100 mL of a 0.01 M buffer is 10mL.
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What was the first expert system developed to determine the chemical structure of molecules?
Dendral was the first expert system developed to determine the chemical structure of molecules.
A molecule refers to a set of (2) or more atoms that are chemically bonded collectively, which allows you to form the smallest essential unit of a chemical compound. additionally, molecules are capable of taking elements in a chemical reaction.
A molecule is the smallest particle of a substance that has all of the physical and chemical houses. Molecules are made up of one or extra atoms. A molecule is a hard and speedy of or greater atoms held together via the use of a way of appealing forces called chemical bonds.
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If initially there are 8.0 kg of cesium-137 present in a sample, how many kg will remain after 60.0 years
Answer:
2 kg
Explanation:
the half life of cesium is approx 30 years
60 years is 2 half lives
8 kg * 1/2 * 1/2 = 2 kg
A
What type of reaction is illustrated?
C₂H4+302 → 2CO₂ + 2H₂O
combustion
decomposition
double
replacement
Answer:
A.) combustion
Explanation:
Combustion reactions are a specific type of redox reaction which always have the same general structure: CₓHᵧ + O₂ ---> H₂O + CO₂ + heat/light
Decomposition reactions are reactions which involve a molecule breaking down into smaller compounds/elements. They have the general structure: AB ---> A + B
Double replacement reactions are reactions in which the cation of one compound is swapped with the cation of another compound. They have the general structure: AB + CD ---> AD + CB
Carbon-14 can be used to date remains as far back as ____________.
A. 60,000 years
B. the 1940's
C. 710 million years
D. 5700 years
A. Carbon-14 can be used to date remains as far back as 60,000 years.
What is carbon dating?Carbon dating is a method for determining the age of an object containing organic material by using the properties of radioactive isotope of carbon.
Carbon-14 dating can be used to estimate the age of carbon-bearing materials up to about 58,000 to 62,000 years old.
Thus, Carbon-14 can be used to date remains as far back as 60,000 years.
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25. Which is an irreversible process?
1) mixing of two gases by diffusion
2) Evaporation of water at 373k and 2atm
pressure
3) Dissolution of Nacl in water
4) All are correct
(S
The answer is 1) mixing of two gases by diffusion.
Once 2 gases are mixed by diffusion, they cannot be obtained from the mixture of gases. Hence, it is considered to be an irreversible process.
What is the element with the abbreviated electron configuration [kr]5 s 24 d 8?
The element with the abbreviated electron configuration is palladium.
Abbreviated electron configurationsElectron configurations can be abbreviated using the noble gas configuration. The noble gas elements have completely filled orbitals.
The noble gases are:
Helium with an atomic number of 2Neon with an atomic number of 10Argon with an atomic number of 18Krypton with an atomic number of 36And so on.For example, an element with the atomic number 4 can have its electron configuration written as [He] [tex]2S^2[/tex].
An element with the abbreviated atomic number [Kr] [tex]5s^2[/tex] [tex]4d^8[/tex] has a total of the atomic number of Kr + 2 + 8.
36+2+8 = 46 electrons.
The element with the atomic number of 46 is palladium.
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A sample of gas has its number of molecules quadrupled, its Kelvin temperature doubled, and its volume tripled. By what factor has the new pressure changed relative to the original pressure
The new pressure changed relative to the original by a factor of 8/3.
What is the change in the pressure?Using the ideal gas equation;
PV = nRT
P = pressure
V = volume
n = number of moles
R = gas constant
T = temperature
P1 = nRT/V
P2 = 4n * R * 2T/3V
Hence;
P2/P1 = 4n * R * 2T/3V ÷ nRT/V
P2/P1 = 4n * R * 2T/3V * V/nRT
P2/P1 =4 * 2/3
= 8/3
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What best defines an extensive property of a substance? (4 points) A property that is observable A property that is measurable A physical property that depends on the sample size A physical property that is not dependent on sample size
Answer:
A physical property that depends on the sample size
Explanation:
Provide the IUPAC name for the compound below. a. 1-chloro-4-methylpent-2-yne b. 5-chloro-2-methylpent-3-yne c. sec-butylchloromethylacetylene d.1-chloro-4,4-dimethylbut-2-yne
Answer: a. 1-chloro-4-methylpent-2-yne - [tex]C_6H_9Cl[/tex]
b. 5-chloro-2-methylpent-3-yne - [tex]C_6H_7Cl[/tex]
c. sec-butyl chloromethyl acetylene - [tex]C_{12}H_{21}ClO_2[/tex]
d.1-chloro-4,4-dimethylbut-2-yne - [tex]C_6H_9Cl[/tex]
What is the full name of IUPAC?
The full name of IUPAC is International Union of Pure and Applied Chemistry.
The compound's name is typed out first, followed by the base name and the substituents in alphabetical order (derived from the number of carbons in the parent chain). Between numbers and letters are separated by dashes and commas, respectively. The name has no spaces.
Therefore, a. 1-chloro-4-methylpent-2-yne - [tex]C_6H_9Cl[/tex]
b. 5-chloro-2-methylpent-3-yne - [tex]C_6H_7Cl[/tex]
c. sec-butyl chloromethyl acetylene - [tex]C_{12}H_{21}ClO_2[/tex]
d.1-chloro-4,4-dimethylbut-2-yne - [tex]C_6H_9Cl[/tex]
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Why has nuclear fusion been difficult to develop?
A. Fuel for nuclear fusion is very rare.
B. Fusion normally occurs in the vacuum of space and the atmosphere on Earth stops the
reaction.
C. It is hard to recreate the extremely high temperatures and pressures found inside stars.
D. An efficient shape to contain the reaction has not been found.
Answer:
C. It is hard to recreate the extremely high temperatures and pressures found inside stars.
Explanation:
Nuclear fusion occurs when atomic nuclei are forcefully combined to create a new atomic nuclei or subatomic particles. In nature, this process takes place in our Sun and other stars. Within stars, extremely high temperatures and pressures are achieved and cause nuclear fusion to occur. Humans have not yet been successful in recreating the environment necessary to mimic this process.
Which describes the oxidizing agent in a chemical reaction?
the substance that is oxidized because it loses electrons
the substance that is reduced because it loses electrons
the substance that is oxidized because it gains electrons
the substance that is reduced because it gains electrons
The statement that describes the oxidizing agent in a chemical reaction is the substance that is reduced because it gains electrons (option D).
What is a redox reaction?A redox reaction is a chemical reaction in which some of the atoms have their oxidation number changed.
In a redox reaction, there are oxidizing and reducing agents. The oxidizing agent is the substance that receives electrons from another substance, hence, becoming reduced.
Therefore, the statement that describes the oxidizing agent in a chemical reaction is the substance that is reduced because it gains electrons.
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Answer:D
Explanation:
took test
__________ is the use of high energy radiation to kill cancer cells.
Answer:
Radiation therapy is the use of high energy radiation to kill cancer cells.
Answer:
Radiation Therapy.
Explanation:
Also known as radiotherapy, it uses high-energy radiation to damage and/or kill cancer cells.
What is the electron configuration for a calcium atom? 01s². 2s 2.2p5.3s 2.3p 5.4s¹ 02s², 2s ², 2p5.3s 2.3p 6,4s1 01s 2. 2s 2. 2p5.3s 2.3p 5, 452 Ots1,2s2, 2p5.3s 2.3p5,4s¹
Answer:
Ca = 1s²2s²2p⁶3s²3p⁶4s²
Explanation:
Calcium is located in the second column and the 4th row of the periodic table. Thus, there are 2 valence electrons and the highest quantum number is 4. This is represented by 4s². However, all of the previous orbitals and electrons must be listed beforehand, making the entire electron configuration: 1s²2s²2p⁶3s²3p⁶4s².
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The amount, in grams, of carbon tetrachloride that would be present, will be 22.99 grams.
Finding the mass from the number of particlesFor every one mole of any substance, there are 6.022 x [tex]10^{23}[/tex] atoms of particles. This is according to Avogadro.
Now, there are 9 x [tex]10^{22[/tex] particles in this particular carbon tetrachloride.
If 1 mole = 6.022 x [tex]10^{23}[/tex] particles
Then,
9 x [tex]10^{22[/tex] particles = 9 x [tex]10^{22[/tex] x 1/6.022 x [tex]10^{23}[/tex] particles
= 0.1495 moles
Carbon tetrachloride has the chemical formula CCl4 and has a molar mass of 153.82 g/mol.
Recall that: mole = mass/molar mass
Hence, mass = mole x molar mass.
Mass of 0.1495 moles CCl4 = 0.1495 x 153.82 = 22.99 grams
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For a second order reaction, if [A]^-1 is plotted vs. time, which corresponds to the slope of the plot?
a. 1/a
b. K
c. 1/k
d. Ln[a]
e. -k
For a second order reaction, if (A)^-1 is plotted vs. time is straight line with k= slope of the line,Plot the inverse of concentration of a reactnt verus time.
Second order reaction defined as chemical reactions which is the sum of the exponents in the rate of law of the chemical reaction is equal to two.The such reaction is written as the - r=k(A)2 or r= k(A)(B).
Second order reaction is a type of reaction which is depend on the concentrations of one second order or two first order reactants.Reaction proceeds at rate proportional to the square of the product of the concentration of one reactant, or the product of the concentrations of two reactant.
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mass of an atom of element x is equivalent to the total mass of 7 hydrogen atoms. what element represent x ?
Answer:
lithium
Explanation:
The mass of hydrogen is 1 u, so the mass of element x is 7 u, which is approximately the atomic mass of lithium.
In what way did political policies act as a centrifugal force in the Soviet Union during the late 1980s
The government gave the people more freedom to criticize the government which led to nationalist movements
What way did political policies act as a centrifugal force in the Soviet Union during the late 1980s ?In the late 1980s, the economic and social situation in the Soviet Union was tense. The socialist economy was on the verge of collapse, the war in Afghanistan was an assured defeat, and the quality of life for Soviet citizens was appalling.
Due to these situations, the Soviet leader Mikhail Gorbachev decided to carry out a series of economic and political reforms, known as Perestroika and Glasnost, aimed at liberalizing the economy from a pure socialist model to a mixed model, and granting greater rights and civil liberties to the citizens.This led to numerous mobilizations and demonstrations, which further weakened the already weak Soviet political apparatus and made possible the emergence of regionalist nationalisms in the former Soviet nations, especially those subjugated to the power of Russia.Learn more about Soviet Union here:
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Each coin has a mass of 21.94 g and a volume of 2 mL which of the following metals are the coins made of
Answer:
A.
Explanation:
The density of each element represents the mass (grams) per every 1 milliliter Therefore, if each coin is 2 milliliters, you need to divide the given mass by 2.
21.94 grams / 2 mL = 10.97 grams / 1 mL
This matches the density of silver.
Ammonia, NH3, undergoes reaction with oxygen to form nitrogen and water. When 7.00 x 1022 molecules of ammonia react with 6.00 x 1022 molecules of oxygen, what mass of nitrogen results (grams)
Amount of nitrogen produced = 1.624 g
To calculate the moles, we use the equation:
4NH3(g) + 3 O2 (g) ---> 2 N2 (g) + 6 H2O (g) ....(1)
For ammonia:
Putting values in above equation, we get:
Moles of ammonia = 7.00 x 1022 / 6.023 * 10 ^23 = 0.116 mol
Moles of oxygen = 6.00 x 1022 / 6.023 * 10 ^23 = 0.099 mol
For the reaction:
4NH3(g) + 3 O2 (g) ---> 2 N2 (g) + 6 H2O (g)
By Stoichiometry of the reaction,
4 moles of ammonia combine with 3 moles of Oxygen
Thus 0.116 moles of ammonia will combine with= 3/4 * 0.116 = 0.087 of oxygen
Thus ammonia is the limiting reagent as it limits the formation of product.
4 moles of ammonia produces 2 moles of nitrogen
0.132 moles of ammonia will produce=2/4 * 0.116 = 0.058 of nitrogen
Molar mass of nitrogen = 28 g/mol
Amount of nitrogen produced=
No of moles * molar mass = 0.058 * 282 = 1.624 g
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attractive forces between molecules in a solid are stronger
than bonds between atoms in a molecule
Answer:
False
Explanation:
Attractive forces between molecules in a solid are weaker than bonds between atoms in a molecule.
It takes much more energy to break intramolecular bonds (bonds within molecules) than it does to break intermolecular bonds (bonds between molecules). As a result, it is more difficult to break apart one molecule of a solid than it is to break the solid or separate the molecules from one another.
Noble gases are the least reactive elements on the periodic table
True or false
True. Noble gases are the least reactive elements on the periodic table
What are noble gases?They are a group of elements with completely filled orbitals. In other words, they have zero valence electrons.
Without having valence electrons, it becomes difficult for this group of elements to form bonds with other elements either by electron donation or sharing.
However, they can be made to form bonds with other elements under special conditions.
Thus, they are the least reactive of all the elements in the periodic table.
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Answer:
TRUE!"Why?"
The Noble Gases have eight valence electrons, which fill their outer energy level. This is the most stable arrangement of electrons, so noble gases rarely react with other elements and form compounds.
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Which equation agrees with the ideal gas law?
StartFraction V subscript 1 over T subscript 1 EndFraction equals StartFraction V subscript 2 over T subscript 2 EndFraction.
V subscript 1 n subscript 1 equals V subscript 2 n subscript 2.
P subscript 1 n subscript 1 equals P subscript 2 n subscript 2.
StartFraction P subscript 1 over P subscript 2 EndFraction equals StartFraction T subscript 2 over T subscript 1.
The equation for ideal gas law is written as PV = nRT.
What is Ideal gas law?Ideal gas law states that, the volume of a given amount of gas is directly proportional to the number on moles of gas, directly proportional to the temperature and inversely proportional to the pressure.
PV = nRT
where;
P is pressure of the gasV is volume of the gasn is number of molesR is ideal gas constantT is temperatureThus, the equation for ideal gas law is written as PV = nRT.
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Lead(II) oxide from an ore can be reduced to elemental lead by heating in a furnace with carbon. Calculate the expected yield of lead if 50.0 kg of lead oxide is heated with 50.0 kg of carbon.
Find the expected yield of lead:
The expected yield of lead if 50.0 kg of lead oxide is heated with 50.0 kg of carbon is 46 kg
Calculation:
First and foremost, we must correctly write the equation of reaction in order to answer this issue. This is what it is:
PbO(s) + C(s) → Pb(l) + CO (g)
We continue from here. The limiting reactant should be found, however finding out how many moles of each reactant are present is the only way to do so.
The number of moles is calculated using the formula: the mass of each reactant divided by the molar mass of each reactant.
Mass of PbO is 50kg = 50000g
Molar mass of PBO = 223.20g/mol
The number of moles is thus 50000/223.2 = 224 moles
For carbon, mass is also 50kg = 50000g
Molar mass is 12g/mol
Number of moles of carbon = 50000/12 = 4166.6 moles
We can observe from the number of moles that there are more moles of carbon than PbO. This indicates that the limiting reagent is PbO.
So, in order to determine percentage yield, we employ it.
Since we have a mole ratio of 1 to 1, the number of moles of lead created is equal to the number of moles of lead oxide, which is 224.
The molar mass of lead = 207.20 g/mol
The mass of lead formed = moles of lead x molar mass of lead
The mass of lead formed = 207.20 x 224 = 46,412.8 g = 46 kg
Hence, the expected yield is 46 kg.
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Molecular weight and configurational stability of poly [(fluorophenyl) acetylene]s prepared with metathesis and insertion catalysts
A detailed article on formation of poly [(fluorophenyl) acetylene]s prepared with metathesis and insertion catalysts has been given below.
What is Molecular weight and configurational stability of poly [(fluorophenyl) acetylene]s?By polymerizing (2-fluorophenyl)acetylene, (3-fluorophenyl)acetylene, and (4-fluorophenyl)acetylene with catalysts [Rh(1,5-cyclooctadiene) OCH3]2, high-cis PFPhAs and tungsten(VI) oxychloride/tetraphenyltin, respectively, PFPhAs have been created.Size exclusion chromatography, 1H-NMR, and UV-vis methods were used to investigate the molecular weight and configurational stability of both PFPhAs series under varied circumstances at room temperature.The rate of degradation was independent of the F-position on the Ph ring for all samples while they were in the solid state and exposed to the environment. For high-cis polymers compared to their cis/trans counterparts, the rate of breakdown in the tetrahydrofuran solution increased by up to three orders of magnitude. In an aerated tetrahydrofuran solution, there was considerable cis-to-trans isomerization along with the degradation of high-cis PFPhAs.The F-position on the Ph ring showed the similar dependence on the rate of degradation and isomerization. It was proposed that cis-to-trans isomerization, which increases the amount of unpaired electrons on the main chains, hastened the degradation of high-cis PFPhAs in solution. The ortho-substituted isomers shown increased stability compared to the meta- and para-substituted isomers in both the high-cis and cis/trans series of polymers.To know more about isomerization visit: https://brainly.com/question/2226351
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Calculate the number of ions of the following compound :16g of H2CO3
Answer:
1) a) 1.81 × 10²³ molecules (b) 1.93 × 10²³ molecules (c) 0.66× 10²³ molecules
2) a) 0.45× 10²³ions (b) 0.84× 10²³ions (c) 3.6 × 10²³ions
Explanation:
1) Number of molecules:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number.
a) 16g of H₂CO₃
Number of moles = mass/ molar mass
Number of moles = 16 g/ 62.03 g/mol
Number of moles = 0.3 mol
1 mol = 6.022 × 10²³ molecules
0.3 mol × 6.022 × 10²³ molecules /1 mol
1.81 × 10²³ molecules
b) 20g of HNO₃
Number of moles = mass/ molar mass
Number of moles = 20 g/ 63.01 g/mol
Number of moles = 0.32 mol
1 mol = 6.022 × 10²³ molecules
0.32 mol × 6.022 × 10²³ molecules /1 mol
1.93 × 10²³ molecules
c) 30g of C₆H₁₂O₆
Number of moles = mass/ molar mass
Number of moles = 20 g/ 180.156 g/mol
Number of moles = 0.11 mol
1 mol = 6.022 × 10²³ molecules
0.11 mol × 6.022 × 10²³ molecules /1 mol
0.66× 10²³ molecules
2. Calculate the number of ions in the following compounds:
a) 10g of AlCl₃
Number of moles = mass/ molar mass
Number of moles = 10g/ 133.34 g/mol
Number of moles = 0.075 mol
1 mol = 6.022 × 10²³ ions
0.075 mol × 6.022 × 10²³ ions/1 mol
0.45× 10²³ions
b) 30g of BaCl₂
Number of moles = mass/ molar mass
Number of moles = 30g/ 208.23 g/mol
Number of moles = 0.14 mol
1 mol = 6.022 × 10²³ ions
0.14 mol × 6.022 × 10²³ ions/1 mol
0.84× 10²³ions
c) 58 g of H2SO4
Number of moles = mass/ molar mass
Number of moles = 58g/ 98.079 g/mol
Number of moles = 0.59 mol
1 mol = 6.022 × 10²³ ions
0.59 mol × 6.022 × 10²³ ions/1 mol
3.6 × 10²³ions
Explanation:
Which one of the following terms is used to describe a loan wherein each payment is equal in amount and includes both interest and principal
amortized loan one of the following terms is used to describe a loan wherein each payment is equal in amount and includes both interest and principal.
What is an amortized loan?
A loan that is amortized requires the borrower to pay interest and principal over time. A three-year investment yields 5% a year in interest, paid out semi-annually.An amortized loan payment initially covers the interest cost for the period; any balance is applied to the principle balance.What does it mean when a loan is amortized?
A loan that is amortized over a predetermined period of time is a type of financing. The borrower pays the same amount over the course of the loan under this form of repayment plan, with the initial portion going toward interest and the remaining sum being applied to the existing loan principal.Learn more about amortized loan
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The percentage composition of an organic acid is found to be 39.9% C, 6.7% H, and 53.4% O. The molar mass for the compound is 60.0g/mol. What is the molecular formula
Answer:
C₂H₄O₂
Explanation:
To find the molecular formula of the organic acid, you need to (1) determine the mass of each element (from the given percents), then (2) convert grams of each element to moles (via atomic masses), then (3) find the empirical formula, and then (4) find the molecular formula.
(Step 1)
39.9% C -----> 39.9 g C
6.7% H -----> 6.7 g H
53.4% O -----> 53.4 g O
(Step 2)
Atomic Mass (C): 12.011 g/mol
Atomic Mass (H): 1.008 g/mol
Atomic Mass (O): 15.988 g/mol
39.9 grams C 1 mole
---------------------- x ---------------------- = 3.32 moles C
12.011 grams
6.7 grams H 1 mole
-------------------- x --------------------- = 6.65 moles H
1.008 grams
53.4 grams O 1 mole
---------------------- x ---------------------- = 3.34 moles O
15.998 grams
(Step 3)
The empirical formula is made up of the lowest possible amount of each element in the molecule. These amounts can be found by dividing the molar value of each element by the smallest molar value. In this case, the smallest molar value is 3.32 moles C. The calculated values make up the subscripts in the empirical formula.
3.32 moles C / 3.32 = 1 mole C
6.65 moles H / 3.32 = 2 moles H
3.34 moles O / 3.32 = 1 mole O
Empirical Formula: CH₂O
(Step 4)
To find the molecular formula, you first need to determine the molar mass of the empirical formula. Once you have this value, you need to determine how much you need to scale the formula up by. In this case, the molar mass of the empirical formula is half of the molar mass of the molecular formula. Therefore, you need to multiply the amount of each element in the molecule by 2.
Molar Mass (CH₂O): 12.011 g/mol + 2(1.008 g/mol) + 15.998 g/mol
Molar Mass (CH₂O): 30.025 g/mol
30.025 g/mol x 2 = 60.05 g/mol
CH₂O x 2 = C₂H₄O₂
If you have 100 ml of a 0.10 m tris buffer (pka 8.3) at ph 8.3 and you add 3.0 ml of 1.0 m hcl, what will be the new ph?
The new pH is 7.69.
According to Hendersen Hasselbach equation;
The Henderson Hasselbalch equation is an approximate equation that shows the relationship between the pH or pOH of a solution and the pKa or pKb and the ratio of the concentrations of the dissociated chemical species. To calculate the pH of the buffer solution made by mixing salt and weak acid/base. It is used to calculate the pKa value. Prepare buffer solution of needed pH.
pH = pKa + log10 ([A–]/[HA])
Here, 100 mL of 0.10 m TRIS buffer pH 8.3
pka = 8.3
0.005 mol of TRIS.
∴ [tex]8.3 = 8.3 + log \frac{[0.005]}{[0.005]}[/tex]
inverse log 0 = [tex]\frac{[B]}{[A]}[/tex]
[tex]\frac{[B]}{[A]} = 1[/tex]
Given; 3.0 ml of 1.0 m hcl.
pka = 8.3
0.003 mol of HCL.
[tex]pH = 8.3 + log \frac{[0.005-0.003]}{[0.005+0.003]}\\pH = 8.3 + log \frac{[0.002]}{[0.008]}\\\\pH = 8.3 + log {0.25}\\\\pH = 8.3 + (-0.62)\\pH = 7.69[/tex]
Therefore, the new pH is 7.69.
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