The pH after 8.7 mL of 0.191 M NaOH is added to a 25.0 mL sample of 0.150 M hydrazoic acid, HN₃, is 4.415.
To calculate this, follow these steps:
1. Calculate moles of HN3 and NaOH: moles_HN₃ = 0.150 M * 0.025 L = 0.00375 mol; moles_NaOH = 0.191 M * 0.0087 L = 0.00166 mol
2. Determine the reaction: HN₃ + NaOH → NaN₃ + H2O
3. Find moles of HN3 and NaN₃ after reaction: moles_HN₃_remaining = 0.00375 - 0.00166 = 0.00209 mol; moles_NaN3_formed = 0.00166 mol
4. Calculate new concentrations: [HN₃] = 0.00209 mol / (0.025 L + 0.0087 L) = 0.0621 M; [NaN₃] = 0.00166 mol / (0.025 L + 0.0087 L) = 0.0493 M
5. Use Ka expression: Ka = [H+][N3-] / [HN₃] => 1.8 x 10-5 = [H+][0.0493] / [0.0621]
6. Solve for [H+]: [H+] = 2.300 x 10-5 M
7. Calculate pH: pH = -log10([H+]) = -log10(2.300 x 10-5) = 4.415
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A Grignard synthesis begins with 6.00 g of bromobenzene and ends with 3.94 g benzoic acid. What is the percent yield of the benzoic acid
The percentage yield of the benzoic acid is mathematically given as
P= 84.56 %
Question Parameters:
A Grignard synthesis begins with 6.00 g
and ends with 3.94 g benzoic acid.
Generally, if 157 g of bromobenzene produced = 122 g of benzoic acid
Hence,6 g of bromobenzene will produce
X== (122 / 157 ) * 6
X= 4.66 g
Since the experimental yield of benzoic acid = 3.94 g
Therefore the Percentage yield
P = 3.94 / 4.66 * 100
P= 84.56 %
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(e) (i) What are the number average (Mn) and weight average (Mw) molecular weights of a polymer with equal number of chains with molecular weights of 2100, 6600 and 12000 mixed together? (ii) What is the answer if "equal number of chains" is replaced by "equal weights of chains"? (iii) What is the degree of polymerization (DP) of the polymer in the first question, if the repeating units of the three different chains have molecular weights of 126, 324 and 300?
(e) (i) Number average (Mn) = 6,900g/mol
(ii) Mn will remain the same in this case as it does not depend on weight.= 6,900g/mol
(iii) The degree of polymerization (DP) is 4492.
(i) Number average (Mn)
The number average molecular weight (Mn) is the sum of the molecular weights of all polymer chains divided by the total number of polymer chains.
Weight average (Mw)
The weight average molecular weight (Mw) is the sum of the product of the molecular weight and the fraction of the total polymer chains that have that molecular weight.
Using the given formula, let's first calculate the Mn:
(2100 + 6600 + 12000) / 3 = 6,900g/mol
Let's now calculate the Mw:
[(2100 x 2100) + (6600 x 6600) + (12000 x 12000)] / (2100 + 6600 + 12000)= 9966.67g/mol
(ii) Equal weights of chains
Mn will remain the same in this case as it does not depend on weight.
Mw, on the other hand, will change.
The following formula will be used:
2100 x (1/3) + 6600 x (1/3) + 12000 x (1/3) = 6,900g/mol
(iii) The degree of polymerization (DP)
DP refers to the number of repeating units in the polymer chain.
We can calculate the DP using the following formula:
DP = (Mn / M) * NA where M is the molar mass of the repeating unit, and NA is Avogadro's number.
Using the Mn value from part (i) and the given molecular weights for the repeating units, we can calculate the DP:
DP = (6,900 / ((126 + 324 + 300) / 3)) * 6.02 × 1023= 4492.45 (approximately 4492)
Therefore, the degree of polymerization is 4492.
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The weight average molecular weight (Mw) of the polymer will be \($$M_w=\frac{1\times2100^2+1\times6600^2+1\times12000^2{1\times2100+1\times6600+1\times12000}=8,580\;g/mol$$\).
Weight average molecular weight (Mw) of the polymer will be \($$M_w=\frac{1.0587\times2100^2+1.0587\times6600^2+1.0587\times12000^2{1.0587\times2100+1.0587\times6600+1.0587\times12000}=8,825\;g/mol$$\).
The degree of polymerization of the polymer in the first question is 25.01.
Number average (Mn) and weight average (Mw) molecular weights of a polymer are calculated using the following formula:
\($$M_n = \frac{\sum N_iM_i}{\sum N_i}$$\)
and
\($$M_w = \frac{\sum N_iM_i^2}{\sum N_iM_i}$$\)
where Ni is the number of chains with molecular weight Mi.
(i) When the number of chains with molecular weights of 2100, 6600, and 12000 are mixed together:
Molecular weight (M) Number of chains (N) 2100 1 6600 1 12000 1
Total 3
The number average molecular weight (Mn) of the polymer will be:
\($$M_n=\frac{1\times2100+1\times6600+1\times12000}{1+1+1}= 6,900\;g/mol$$\)
The weight average molecular weight (Mw) of the polymer will be:
\($$M_w=\frac{1\times2100^2+1\times6600^2+1\times12000^2}{1\times2100+1\times6600+1\times12000}=8,580\;g/mol$$\)
(ii) When the equal weights of chains are mixed together:
The total weight of the chains is:
2100 + 6600 + 12000 = 20,700 g
Number of chains with molecular weight 2100 = 2100 x n1
Number of chains with molecular weight 6600 = 6600 x n2
Number of chains with molecular weight 12000 = 12000 x n3
So, the total weight of each group of chains will be
n1M1 + n2M2 + n3M3.
Now, we can calculate the values of n1, n2, and n3 as follows:
n1 = 6600 x n2n2 = 12000 x n3M1 + M2 + M3 = 2100 + 6600 + 12000 = 20700n1M1 + n2M2 + n3M3 = 20700
Equating the value of n1 in terms of n2 and n3 and substituting it in the equation above:
n1 = 6600 x n2
\($$\frac{6600}{n1}=n2$$\)
\($$\frac{12000}{n2}=n3$$\)
\($$n1=\frac{20700}{2100+6600+12000}=0.1739$$\)
n2 = 0.0208, n3 = 0.0052
Therefore, the number of chains with molecular weight 2100 = 0.1739 x 2100 / 6600 x 0.1739 x 6600 = 0.0208 x 12000 / 6600 x 0.0208 x 6600 = 0.0052 x 2100 / 6600 x 0.0052 x 12000 ≈ 1.0587
Number average molecular weight (Mn) will be:
\($$M_n=\frac{1.0587\times2100+1.0587\times6600+1.0587\times12000}{1.0587+1.0587+1.0587}= 7,170\;g/mol$$\)
Weight average molecular weight (Mw) of the polymer will be:
\($$M_w=\frac{1.0587\times2100^2+1.0587\times6600^2+1.0587\times12000^2}{1.0587\times2100+1.0587\times6600+1.0587\times12000}=8,825\;g/mol$$\)
(iii) The degree of polymerization (DP) of the polymer in the first question will be:
Number of chains with molecular weight 2100 = 1
Number of chains with molecular weight 6600 = 1
Number of chains with molecular weight 12000 = 1
The molecular weight of the repeating units of the three different chains have molecular weights of 126, 324, and 300 respectively.
Therefore, the degree of polymerization (DP) of the polymer in the first question will be:For 2100 chain,
\($$n_1=\frac{2100}{126}=16.67$$\)
For 6600 chain,
\($$n_2=\frac{6600}{324}=20.37$$\)
For 12000 chain,
\($$n_3=\frac{12000}{300}=40.00$$\)
So, the average degree of polymerization (DP) is:
\($$DP=\frac{1\times16.67+1\times20.37+1\times40.00}{1+1+1}=25.01$$\)
Therefore, the degree of polymerization of the polymer in the first question is 25.01.
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When is International Day of Forests?
Answer:
21 March
Explanation:
hope its helpful
review the terms and their definition in the mini glossary. write a sentence that shows your understanding of one of the properties of metals.
Metals are ductile and malleable. Metals are efficient heat and wires. Metals could be treated but are lustrous (sparkly). Iron are solids when room temperature (except arsenic, which is fluid). Metals are resilient and powerful.
What does the term "metals " mean?Metal is a solid substance that is hard, lustrous, ductile, fusible, and ductile and carries heat and electricity. Materials that have a propensity to give electrons include metals. They have an electropositive makeup.
Why are metals so valuable?Metals are excellent building materials. Strength, hardness, and rigidity are just a few of the qualities that metals possess. Metals may be cooked and formed into anything, from a little paperclip to an enormous aircraft. They are important for generators in cooking utensils due to their outstanding thermal and electrical conductors.
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When writing the formulas for a compound that contains a polyatomic ion, ... ?
Answer:
The cation is written first in the name; the anion is written second in the name. Rule 2. When the formula unit contains two or more of the same polyatomic ion, that ion is written in parentheses with the subscript written outside the parentheses.
When writing the formula of a compound that contains polyatomic ion, the metal is written first followed by the central atom in the ion and then other atoms that surround the central atom.
A poly atomic ion refers to an ion that comprises of more than one atom. Such ions are common in chemistry. Examples of polyatomic ions include; PO4^3-, BH4^- etc.
When writing the formula of a compound that contains a polyatomic ion, the metal is written first then the central atom in the ion follows before other atoms that surround the central atom in the ion.
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which of the following is not one of the properties of water? group of answer choices it is a universal solvent. it stabilizes temperature. it is cohesive. density increases when frozen.
"Density increases when frozen" is not the property of water. The correct option is (d).
Water is an essential element of life on earth, and it has various unique properties that make it an extraordinary compound. However, some properties are not applicable to water, and one of them is the density increases when frozen.
Other properties of water and how they affect life on earth are as follows.
1. It is a universal solvent: Water is known as a universal solvent because it can dissolve many substances like salt, sugar, and other chemicals. It has a high dielectric constant, making it an excellent solvent for many ionic compounds. Water molecules have polarity, and they attract other charged ions and dissolve them.
2. Stabilizes temperature: Water has a high specific heat capacity, which means it can absorb heat without changing its temperature. This property helps to stabilize the temperature of the oceans and other water bodies. Water can also release heat and cool the environment when it evaporates. This property helps to regulate the temperature of the earth's surface.
3. Cohesive: Water molecules have hydrogen bonds between them, making them cohesive. Cohesion is a property that makes the water molecules stick together. This property is responsible for capillary action in plants and water transportation in animals. The cohesive force of water is also responsible for the surface tension of water, which allows insects to walk on the water's surface.
4. Density increases when frozen: Water is an exception to the typical behavior of most compounds that contract when cooled. Water expands when cooled below its freezing point and becomes less dense. This behavior is a unique property of water and is responsible for the survival of aquatic life during winter.
Therefore, the property of water that is not applicable to water is the density increases when frozen.
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you are asked to prepare 100ml of a 1.5m kbr solution. what mass of kbr do you need? show your calculation in the space provided.
To prepare 100ml of a 1.5m kbr solution. To find mass of kbr we need
we can use the formula:
mass = molarity x volume x molar mass
where molar mass of KBr is 119.00 g/mol.
So,
mass = 1.5 M x 100 ml x (119.00 g/mol) / 1000 ml/L
mass = 1.785 g
Therefore, 1.785 g of KBr is required to prepare 100 ml of a 1.5 M solution.
Potassium Bromide, sometimes known as KBr, is a salt that is commonly used as an anticonvulsant and sedative.
Other names for potassium bromide include Kalii bromidum, tripotassium tribromide, and bromide salt of potassium.
The odourless potassium bromide salt has a sharp, bitter salty flavour and is available as white crystals, colourless crystals, or white granular solids. Aqueous KBr solutions have a pH of 7.
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Choose all of the following that are FALSE.
A. Paper makes up the largest proportion of MW in the United States.
B. If you wash your plastic bottles with warm water that was heated via coal-generated electricity before recycling them, then recycling your plastic bottles could release more carbon into the atmosphere than throwing them
away.
C. Total waste generation in the United States has been steadily increasing since about 1950. Globally. D. solid waste management costs are expected to begin decreasing as waste management
technology gets cheaper.
A. Paper makes up the largest proportion of MW in the United States. (False) C. Total waste generation in the United States has been steadily increasing since about 1950. Globally. (False)
D. Solid waste management costs are expected to begin decreasing as waste management technology gets cheaper. (False)
The false statements are A, C, and D.
A. Paper does not make up the largest proportion of municipal waste (MW) in the United States. While paper waste is significant, it is not the largest component. Other materials like food waste, plastics, and metals also contribute to MW.
C. Total waste generation in the United States has not been steadily increasing since about 1950. In fact, waste generation rates have fluctuated over the years due to various factors such as population growth, consumption patterns, and waste management practices.
D. Solid waste management costs are not expected to decrease as waste management technology gets cheaper. While advancements in technology can lead to more efficient waste management processes, they often come with their own costs, such as implementation, maintenance, and regulatory compliance. These factors can offset any potential cost savings and may even lead to an increase in waste management costs over time.
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Help needed ASAP, I will mark your answer as brainliest.
What does the charge tell you about an atom?
Brainliest!!!!!!
Answer:
The charge will tell you if the atom is neutral, positive, or negative. "The charge of an atom is the number of protons minus the number of electrons."
What do chemists study?
A. Chemists study living organisms and the energy required to
sustain life.
B. Chemists study the relationships between hypotheses and
theories.
C. Chemists study planets.
D. Chemists study atoms and how they behave in the physical world.
Answer:
D
Explanation:
What is the ratio of hydrogen nuclei to helium nuclei in the solar wind sample that you have gathered
We can see here that in order to find the the ratio of hydrogen nuclei to helium nuclei in the solar wind sample that you have gathered, here is guide:
Determine the number of hydrogen nucleiDetermine the number of helium nucleiCalculate the ratio: Divide the number of hydrogen nuclei by the number of helium nuclei to obtain the ratio.What is ratio?A ratio is a mathematical comparison between two or more quantities or numbers. It expresses the relationship or proportion between the quantities being compared. Ratios are often written in the form of a fraction or using a colon (:).
Ratios can be simplified or expressed in different forms, such as as a decimal or percentage.
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An isotope contains 47 protons, 47 electrons, and 60 neutrons. What is the identity of the isotope?
Answer:
To find the identity of the isotope we must first calculate the mass number
Mass number (M) = A + Z
Where
A is the atomic number
Z is the neutron number
A = 47
Z = 60
M = 60 + 47 = 107
From the options above
The answer is option A
Hope this helps you
According to the periodic table, which statement
correctly describes the change from a neutral atom
of an element to its ion?
A. A fluorine atom forms a F-' ion by losing
one electron.
B. A sodium atom forms a Nation by losing
two electrons.
C. A magnesium atom forms a Mg+2 ion by
gaining two electrons.
D. A phosphorus atom forms a p- ion by
gaining three electrons
The ____number can vary among atoms of the same element.
Answer:
Mass number
Explanation:
All atoms of the same element have the same number of protons, but some may have different numbers of neutrons, which would cause a different mass number
Answer:
The answer is mass number
10. When a substance is analyzed using an electron microscope, it is found
to contain only one type of atom.
This substance is
A an element
B. a mixture
C. neither of the other three
D. a compound
Fluorine, chlorine, and iodine are examples of
Answer:
Halogens
Explanation:
The halogens are a series of non-metal elements from group 17 of the periodic table (formerly VII). The halogens include fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At).
Answer:
halogens
Explanation:
just did the test on edg!
what is the molarity of a solution in which 10.0 g of AgNO3 is dissolved in 5 L of a solution
Answer:
no of moles = given mass/molar mass
no of moles = 10/169.87 =0.058moles
molarity = number of moles of solute/volume of solution in litre
molarity = 0.058/5
molarity = 0.0116
4. Plant cells have large, round vacuoles they primarily use for-
Plant cells have large, round vacuoles they primarily use for water storage so that will be option A.
A vacuole is a membrane-bound organelle found in plant, fungus, and animal cells, as well as certain protist, animal, and bacterial cells. Vacuoles are simply confined compartments filled with water holding inorganic and organic molecules in solution, including enzymes, while in certain situations they may also include solids that have been absorbed.
Vacuoles are generated by the fusing of several membrane vesicles and are just bigger versions of these. The organelle has no fixed form or size; its structure changes depending on the needs of the cell.
The role and relevance of vacuoles vary substantially depending on the kind of cell in which they are found, with plants, fungi, and some protists having far more prominence than animals and bacteria. In general, the vacuole performs the following functions:
Isolating materials that might be toxic or pose a risk to the cellstoring waste productsWater storage in plant cellsLearn more about Vacuoles:
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Complete question:
Plant cells have large, round vacuoles they primarily use for -
A) water storage
B) energy production.
C) protein synthesis.
D) waster removal
Based on the formula given in the chapter 7 nutrition moodle outline, how much protein should a person consume daily if he/she weighs 100 pounds?
If he/she weighs 100 pounds, 36 gm of protein should be consumed by a person if he/she weighs 100 pounds.
It is very important to maintain a balanced diet.
There are two ways to find the amount of protein consumed per day by a person.
1. Weight in pounds, multiplied by 7, divided by 20
2. And the second way is to simply multiply the weight in pounds by 0.36.
As we all know, it is very important to consume all the nutrients in order to maintain a healthy body. Protein is one of the seven essential nutrients in a well-balanced diet.
It is used to repair cells and also helps with growth in children.
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Which are examples of science rather than pseudoscience? Check all that apply.
Answer:
The second choice and the fourth choice are both based on science fact. The others are examples of pseudoscience.
How many electrons are in the element
Answer:
Number of electrons differ from one elements to other elements .means that each elements have different numbers of electrons
for ex Hydrogen has only one electron whereas helium has 2 electrons
Number of electrons = Atomic number
Atomic number of an element tells the no. of electrons in it.
For ex
Hydrogen ( atomic no. 1 ) ---- 1 electron
helium ( atomic no 2 ) ---- 2 electron
Lithium (atomic no.3 ) ---- 3 electron
A gas sample has a volume of 0.329 L with an unknown temperature. The same gas has a volume of 0.219 L when the temperature is 30. °C, with no change in the pressure or amount of gas. Part A What was the initial temperature, in degrees Celsius, of the gas? Express your answer as an integer and include the appropriate units. μ μA Ω % O Å SSS ?
The initial temperature in degrees Celsius, of the gas, given that the gas has volume of 0.219 L when the temperature is 30 °C is 182.19 °C
How do i determine the initial temperature of the gas?From the question given above, the following data were obtained:
Initial volume (V₁) = 0.329 LFinal pressure (P₂) = 0.219 LFinal temperature (T₂) = 30 °C = 30 + 273 = 303 KInitial temperature (T₁) =?Now, we can obtain the initial temperature of the gas by using the Charles' law equation as shown below:
V₁ / = V₂ / T₂
0.329 / T₁ = 0.219 / 303
Cross multiply
T₁ × 0.219 = 0.329 × 303
Divide both side by 130
T₁ = (0.329 × 303) / 0.219
= 455.19 K
Subtract 273 to obtain answer in °C
= 455.19 - 273 K
= 182.19 °C
Thus, from the above calculation, we can conclude that the initial temperature is 182.19 °C
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Egyptian papyrus with 63% of its original carbon-14 atoms what is the age year
Answer:
help me
Explanation:
plz
Hydrogen atoms are excited by a laser to the =4 state and then allowed to emit.
What is the maximum number of distinct emission spectral lines (lines of different wavelengths) that can be observed from this system? Calculate the wavelength of the 4⟶3 transition.
Answer:
1875 nm
Explanation:
Given the Rydberg formula for hydrogen: 1/λ = R(1/n₁² - 1/n₂²)
where R ≈ 1.097* 10^7 /m
Hence;
1/λ = 1.097* 107/m * (1/3² - 1/4²) = 5.3 * 10^5/m
λ = 1.875 * 10-6 m = 1875 nm
HELP PLEASE || TEN PTS WILL MARK BRAINLEST ||Reaction B could produce a substance with a pH of...
Group of answer choices
4.
14.
10.
7.
Answer:
the answer is 4
Explanation:
i took the test and got it right and i would recommend using quizlet it has these flash cards and the answers are there you just click on the one that says your question and it will say your answer on the back. It helps with most of my test! Hope this helps (:
If there are 8.59 x 10^22 molecules of NaCl in a salt shaker, what is the mass of NaCl?
If there are 8.59 × 10²² molecules of NaCl in a salt shaker, the mass of the substance is 8.37grams.
How to calculate mass?The mass of a substance can be calculated by multiplying the number of moles of the substance by its molar mass as follows:
mass = no of moles × molar mass
However, the number of moles must be calculated from the number of molecules as follows:
no of moles = 8.59 × 10²² ÷ 6.02 × 10²³
no of moles = 1.43 × 10-¹moles
molar mass of NaCl = 58.5g/mol
mass of NaCl = 58.5 × 0.143 = 8.37g
Therefore, 8.37grams is the mass of the salt in the shaker.
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What is the purpose of an experiment as a part of the scientific method
Answer:
To test the hypothesis
Explanation:
a graduated cylinder with a mass of 105.56 g has 45.4 ml of a certain liquid added to it. the mass of the cylinder and the liquid is 136.15 g. what is the density of this liquid?
The density of the liquid is 0.794 g/mL.
To calculate the density of the liquid, we can use the formula:
Density = Mass / Volume
Given information:
Mass of the graduated cylinder = 105.56 g
Volume of the liquid = 45.4 mL
Total mass of cylinder and liquid = 136.15 g
To find the mass of the liquid, we subtract the mass of the cylinder from the total mass:
Mass of the liquid = Total mass - Mass of the cylinder
Mass of the liquid = 136.15 g - 105.56 g
Mass of the liquid = 30.59 g
Now we can calculate the density:
Density = Mass of the liquid / Volume of the liquid
Density = 30.59 g / 45.4 mL
Converting mL to cm³ (since 1 mL = 1 cm³):
Density = 30.59 g / 45.4 cm³
Density = 0.674 g/cm³
Rounding to three decimal places, the density of the liquid is approximately 0.794 g/mL.
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Calculate the volume of a liquid with a density of 5.45/mL and a mass of 65 g
Answer:
11.93 mLExplanation:
The volume of a substance when given the density and mass can be found by using the formula
\(volume = \frac{mass}{density} \\\)
From the question we have
\(volume = \frac{65}{5.45} \\ = 11.926605\)
We have the final answer as
11.93 mLHope this helps you