help? please and thank you! very much appreciated

The value of the mole is equal to the number of atoms in exactly 12 grams of pure carbon-12. 12.00 g C-12 = 1 mol C-12 atoms = [tex]6.02*10^{23}[/tex] atoms.

The mole is a common unit of measurement in chemistry for the amounts of reactants and products in chemical processes. Previously, "mole of molecules" and "mole of atoms" were denoted by the terms gram-molecule and gram-atom, respectively. The quantity of dissolved material per unit volume of solution is known as a solution's molar concentration, and the unit generally used to describe this quantity is moles per litre(mol/L).

The ratio of a sample's mass to the substance's total mass is known as the molar mass of a material. The number of moles in the sample serves as a measure of the substance's quantity.

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A solid material physically changing into a liquid is called melting. When brought to room temperature, chocolate can simply solidify because it doesn't undergo any chemical changes.

The average distances between the molecules of the chocolate increase as it melts because they spread out more. This is the reason why, after melting, they appear as liquids. Melting is typically thought of as merely a physical transformation. This is so that the chocolate's chemical composition is unaltered.

The transformation of a solid state into a liquid state is referred to as melting. The species involved or their chemical makeup remain unchanged during melting. Melting is therefore a physical characteristic.

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The mechanism for the reaction of pent-2-one with methoxide. In all three boxes add lone pair electrons and nonzero formal charges for the given species is attached below in image.

Methoxides are organic salts having a CH3O anion in organic chemistry. These alkoxides are the most basic. Although other metal-cation compounds including lithium, rubidium, and caesium methoxide exist, sodium and potassium methoxide are the most commonly used.

In order to create a poly ether with a high molecular weight, it is utilized as an initiator of an anionic addition polymerization with ethylene oxide. Both sodium methoxide and its potassium-prepared equivalent are routinely employed as catalysts in the synthesis of biodiesel on a large scale.

Thus, The mechanism for the reaction of pent-2-one with methoxide. In all three boxes add lone pair electrons and nonzero formal charges for the given species is attached below in image.

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The characteristic must be the only difference between the two samples is B-they have different dimensions.

A metallic is a material that, whilst freshly prepared, polished, or fractured, suggests a lustrous appearance, and conducts energy and warmth exceptionally well. It become explicitly said withinside the query that the each samples are precisely portions of the equal metallic. If this is so, portions of the equal metallic should have the equal density, comprise the equal amount of depend, have the equal boiling factor and feature the equal quantity of depend in keeping with unit volume.

Thus, the correct option is B.

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Complete question:

Two pieces of the same metal or placed on the table with the piece of metal have the same density mass and texture which characteristic must be the only difference between the two samples

A-they contain a different amount of matter per unit volume

B-they have different dimensions

C-they are made up of a different type of matter

D-they have different boiling points

The osmolarity of a 20% NaCl solution is 6.8 osmoles/L.

What is osmolarity?

In contrast to osmolality, which refers to the number of solute particles per kilogram of solvent, osmolarity refers to the number of solute particles per liter of solution.

20 % Sodium chloride:

Convert percent to molarity: 20 gm / 100 ml = 200 gm / L

Sodium is 22.99 g and Chlorine is 35.45 g,

Therefore, the molecular weight of Sodium chloride is 22.99 + 35.45, that is 58.44 grams per mole.

Molarity of Sodium chloride = 200 gm/L / (molecular weight of Sodium chloride) = 200 / 58.44 = 3.4 M

There are 2 osmoles of Sodium chloride per mole, so:

Osmolarity of 20% Sodium chloride = Molarity X 2

osmolarity = 3.4 X 2

osmolarity = 6.8 osmoles/L

Therefore, the osmolarity of a 20% Sodium chloride solution is 6.8 osmoles/L.

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The solute that will lower the freezing point of 1 kg of water to 3.72 C is sodium chloride (NaCl).

A solute is any substance that is dissolved in a liquid to form a solution. It can be either a solid, a liquid, or a gas. Solutes are typically dissolved in a liquid to form a homogenous mixture, and the liquid itself is called the solvent. Examples of solutes include sugar, salt, and other minerals in water, as well as oxygen, nitrogen, and carbon dioxide in air. As solutes are dissolved, the concentration of the solute in the solvent increases, resulting in a decrease in the amount of solvent present.

When a substance such as NaCl is dissolved in water, the freezing point of the water is lowered. This is due to the fact that the solute molecules interfere with the hydrogen bonding of the water molecules, which makes it harder for them to form a crystalline structure as the temperature decreases, thus reducing the freezing point.

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As the volume is expanded, it implies that the liquid's liquid particles have characteristics of having vast intermolecular gaps (water). Liquid water has open spaces between its particles, which are not securely connected.

Traditionally, pictures that connect two scenes together are transitioned between using the dissolve editing technique. A dissolve is a progressive change from one image to the next as opposed to a direct cut from one shot to the next.

Water allows substances to dissolve, including salt, sugar, and coffee. These things dissolve. Warm or hot water typically helps them dissolve more quickly and more effectively. Sand and pepper are soluble in hot water, but not at room temperature.

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The most likely mistake responsible for the error in the measured absorbance is that The student added too little solute to the acetone before measuring its absorbance.

Spectrophotometry is a branch of electromagnetic spectroscopy that deals with quantifying a material's reflection or transmission properties as a function of wavelength. Absorbance (A), also known as optical density, is the quantity of light absorbed by a solution (OD). Transmittance is the quantity of light that passes through a solution.

A spectrophotometer is a device that monitors the number of photons (light intensity) absorbed when a sample solution passes through it. The spectrophotometer may also be used to measure the quantity of a known chemical substance (concentrations) by measuring the intensity of light observed. Absorbance is the quantity of light of a specific wavelength that a given substance prevents from passing through it.

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The amount of 38Sr90 produced from a nuclear reactor accident that will take half  lifetime to dissipate is 99.9778%.

The half-life of a reaction is the length of time required for the reactant concentration to decrease to half its initial value. A first-order reaction's half-life is a constant that is correlated with its rate constant: t1/2 = 0.693/k.

A radioactive element's half-life is the amount of time it takes for it to decay to half of its original value. It can be concluded from this that a source's activity has a half-life if it takes some time before it drops to half its starting value.

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Sub is going to be the prefix. The basic building blocks of atoms will be the right response.

It will be smaller than the bigger object in terms of composition. They will thus be smaller than an atom. Atoms are larger than subatomic particles. They are going to be the atom's building blocks. So the fundamental constituents of atoms will be the right response in this case. Protons, neutrons, and electrons—the particles that we know make up atoms—are also referred to as subatomic, of course. Thus, we refer to them as subatomic particles. They are the subatomic particles that go towards the creation of an atom. Okay, so that would be the proper response. that second response choice.

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Cornstarch and water comes under suspension mixture in which a solid solute  dispersed into a liquid solvent .

When we press the mixture quickly, the starch molecules comes close together. Due to this the water to get trapped between chains of starch and create a semi-rigid structure.

There in reality is no chemical reaction which occurs between them as the cornstarch still remains cornstarch at the end of the reaction.

Just a very light bond is formed between them which can be broken easily.

The viscosity of the fluid is increased leading to addition of  some other interesting properties to the substance.

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A molecule of CO2 is a nonpolar molecule, even though the bonds between the carbon atom and the oxygen atoms are polar. This is due to the fact that the two polar bonds in the molecule cancel each other out.

The oxygen atoms in CO2 have a partial negative charge due to their higher electronegativity, while the carbon atom has a partial positive charge. These two polar bonds create a dipole moment in the molecule, but the two dipoles point in opposite directions and thus cancel each other out.

The fact that the two polar bonds cancel out each other is known as “molecular geometry”. This describes how the atoms of a molecule are arranged in space. In the case of CO2, the molecule has a linear arrangement of atoms, meaning that the two oxygen atoms are arranged on opposite sides of the carbon atom. This arrangement creates a symmetrical molecule, where the two dipoles of the polar bonds are facing each other and canceling each other out.

In addition to the cancellation of the dipole moments, the nonpolarity of CO2 is also due to its low polarity. The polarity of a molecule is determined by the difference in electronegativity between the atoms that make up the molecule. In the case of CO2, the difference between the electronegativities of the carbon and oxygen atoms is relatively low, meaning that the resulting molecule is nonpolar.

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You can safely keep freshly potentially dangerous foods, such as cooked meat and foods that contain meat, milk products, prepared vegetables and fruits cooked pasta and rice and cooked as well as processed foods containing eggs, at temperature changes in the danger zone, or between 5° C and 60° C, for up to 2 hours or 4 hours. This information is provided by the 2 Hour/ 4 Hour Rule.

Strong food safety precautions have been implemented as a result of reduction strategies that have been used to reduce the frequency of salmonella-related foodborne illnesses. These tactics are centered on the Food Standards Code, which also incorporates the alternative temperature control technique known as the "2-hour / 4-hour rule."

Flavor enhancers, food safety, labeling, and foods that require prior approval, such as genetically modified foods, are all covered by the Food Standards Code.

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Conjugate base for each acid of H₃PO₄,HSO  and NH  respectively is H₂PO₄[tex]^-[/tex],SO[tex]^-[/tex],NH₂[tex]^-[/tex].

Acids are defined as substances which on dissociation yield H+ ions , and these substances are sour in taste.Compounds   such as HCl, H₂SO₄ and HNO₃ are acids as they yield H+ ions on dissociation.

According to the number of H+ ions which are generated on dissociation acids are classified as mono-protic , di-protic ,tri-protic and polyprotic  acids  depending on the number of protons which are liberated on dissociation.

Acids are widely used in industries  for  production of fertilizers, detergents batteries and dyes.They are used in chemical industries for production of chemical compounds like salts which are produced by neutralization reactions.

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The Lewis structure of the most stable form of sodium, oxygen, calcium and chlorine.

Diagrams that show the chemical bonds between the atoms of a molecule are known as Lewis dot structures, also known as electron dot structures. Additionally, they show the total number of lone pairs found in each of the atoms that make up the molecule. Lewis structures, also known as electron dot structures or Lewis structures, are quite prevalent. According to Lewis, an acid is an electron pair acceptor and a base is an electron pair giver. One dot is included in a Lewis Electron Dot Formula along with the symbol of the element and each valence electron. The steps to explain the electron dot formula are listed below. Note down a skeletal structure using only the element symbols that shows a realistic bonding pattern.

Hence, Lewis structure depict possibilities of bonding.

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We can determine whether a compound is ionic or covalent by comparing their bonds. If a compound will contain ionic bonds then they are ionic in nature whereas if it contains covalent bond they are covalent in nature.

The compounds formed of ionic bonds are made up of metals so they are metallic in nature as  ionic compounds contain a metal bonded to a nonmetal.

They  form crystals and typically have high melting and boiling point and  are hard and brittle, and form electrolytes in water.

Whereas in case of covalent compounds they  are made up of nonmetals bonded to one another. Covalent compounds have lower melting and boiling points as compared to ionic compounds  they are softer in comparison  and are electrical insulators.

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The increasing energy order of the quantum numbers is  III < II < I.

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The photoelectrons' kinetic energy increased with an increase in light frequency, and the current increased with a rise in light amplitude.

What is demonstrated by the photoelectric effect?

The current increased with a rise in light amplitude, and the kinetic energy of the photoelectrons increased with a rise in light frequency.

What does the photoelectric effect prove?

Light can be categorised as a wave because it demonstrates all three of the essential features of a wave—interference, diffraction, and polarisation.

The photoelectric effect, however, only makes sense if we consider light to be made up of tiny energy packets (particles) known as photons; in other words, the photoelectric effect proves that light is a particle.

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If a container is placed on a hot plate, the kinetic energy of molecules inside the container will increase.

It is a fundamental theory of thermodynamics that energy cannot be produced and neither be destroyed. So obviously from the fundamental theorem of thermodynamics, the first two options in the given question ( some kinetic energy would be produced and some kinetic energy would be destroyed ) are obviously wrong.

Since the container is placed on a hot plate, the heat energy will get transferred from the plate to the container, and hence the molecules inside the container will get heated and excited. Therefore the kinetic energy of molecules inside the container will increase.

So basically, in this case, the heat energy of the plate is converted to the kinetic energy of molecules inside the container.

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A substrate enters the energetic site of the enzyme. This bureaucracy the enzyme-substrate complicated.

The response then occurs, changing the substrate into merchandise and forming an enzyme merchandise complicated. The merchandise then go away the energetic site of the enzyme. The first step of an enzyme catalyzed response is catalytic turnover the binding of substrate via way of means of the enzyme the discharge of product dissociation of the ES complicated ES -> E + P. An enzyme-catalyzed response may be more or less divided into 3 stages: enzyme-substrate binding, "catalysis" and product release.

Thus, the first step of enzyme action is the binding of enzyme and substrate.

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RMS or Root Mean Square value can be calculated by taking the square root of arithmetic mean of squared observations.

It's formula for n values is given by

Xrms = √(x1²+x2²+..... Xn²) /N

RMS is root mean Square can be defined as square root of the mean square. It is the arithmetic mean of the squares of group of values. It can also be called as a quadratic mean and even called as varying function.

So basically by three main steps we can calculate Root mean square

1) To get squares of all the values

2) By calculating average of obtained squares

3) Taking the square root of the average

Thus, RMS or Root Mean Square value can be calculated by taking the square root of arithmetic mean of squared observations.

It's formula for n values is given by

Xrms = √(x1²+x2²+..... Xn²) /N

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The primary distinction between magnesium as well as magnesium oxide is also that magnesium is indeed a chemical element and magnesium oxide is an ionic compound.

Although magnesium as well as magnesium oxide are related, they are not the same. Magnesium is indeed a base element, and magnesium oxide is indeed a magnesium derivative. This latter is also a magnesium compound and salt.

Magnesium is a chemical element with the atomic number (12) as well as symbol Mg. It is classified as just a metal as an element and has all of the features of metallic elements. It is strong and malleable, and it can't be broken down because it is already made up of atoms. Magnesium oxide, in contrast hand, is a compound formed when magnesium reacts with oxygen. It has a unique chemical formula (MgO) that results from an ionic bond. This bond, however, could be broken by chemical decomposition.

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The percentage composition of each isotope, given their various masses is:

The percentage composition of each isotope can be obtained as follow:

Average atomic mass = [(Mass of 1st × 1st%) / 100] + [(Mass of 2nd × 2nd%) / 100]

10.81 = [(10.012 × A) / 100] + [(11.009 × (100 - A) / 100]

10.81 = 0.10012A + 11.009 - 0.11009A

Collect like terms

10.81 - 11.009 = 0.10012A - 0.11009A

-0.199 = -0.00997A

Divide both sides by -0.00997

A = -0.199 / -0.00997

A = 20%

Thus,

B = 100 - A

B = 100 - 20

B = 80%

From the above calculations, we can conclude that the percentage composition of each isotope is:

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Answer:

Explanation:

Caffeine has a structure similar to purine. It is made of eight carbon, ten hydrogen, four nitrogen, and two oxygen atoms. Its chemical formula is C8H10N4O2.

The blood buffer has a pH of 7.4, whereas the blood sample has a carbonic acid content of 0.0013 M.

The chemical compound of hydrogen, carbon, and oxygen is known as carbonic acid (H2CO3).It is produced in minute quantities when water dissolves its anhydride, carbon dioxide (CO2). Two covalent double bonds bind the core carbon atom of carbon dioxide, also referred to as carbonic acid gas, to the two oxygen atoms.

pH = pKₐ + log HCO⁻₃/ H₂CO₃

7.4 = - log(4.3 × 10⁻₇)+ log HCO⁻₃/ 0.0013m

log HCO⁻₃/ 0.0013m = 7.4 - 6.37

log HCO⁻₃/ 0.0013m = 1.03

log HCO⁻₃/ 0.0013m = 10¹°⁰³

HCO⁻₃ = 1.3 ₓ 10⁻².

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Nuclear fusion

Explanation:

To draw a parabola graph, we have to first find the vertex for the given equation.

This can be done by using x=-b/2a and y = f(-b/2a). Plotting the graph, when the quadratic equation is given in the form of f(x) = a(x-h)^2 + k, where (h, k) is the vertex of the parabola, is its vertex form.

parabola

A parabola is a plane curve which is mirror-symmetrical and is approximately U-shaped. It fits several superficially different mathematical descriptions, which can all be proved to define exactly the same curves.

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The oxidation state of an element is calculated by subtracting and the total sum of oxidation states of all the individual atom (excluding the one that has to be calculated) from total charge on the molecule. Therefore, in above given ways we can assign oxidation state.

Oxidation state of an element is a number that is assigned to an element in a molecule that represents the number of electron gained or lost during the formation of that molecule or compound.

a.PO[tex]_4[/tex]³⁻ the oxidation state of P is +5

b. P[tex]_3[/tex]O[tex]_{10}[/tex]⁵⁻the oxidation state of P is +5

c. IO⁻the oxidation state of I is +1

d. NO[tex]_2[/tex]⁻the oxidation state of N is +3

e. N[tex]_2[/tex]O[tex]_2[/tex]²⁻the oxidation state of N is +1

f. PO[tex]_3[/tex]³⁻the oxidation state of P is +3

g. IO[tex]_3[/tex]⁻the oxidation state of I is +5

h. NH[tex]_4[/tex]⁺the oxidation state of N is +3

i. NO⁺the oxidation state of N is +1

j. TeO[tex]_4[/tex]²⁻the oxidation state of Te is +6

k. HPO[tex]_4[/tex]²⁻the oxidation state of P is +5

l. IO[tex]_2[/tex]⁻the oxidation state of I is +3

m. NO[tex]_3[/tex]⁻the oxidation state of N is +5

n. NO[tex]_2[/tex]⁺the oxidation state of N is +5

o. SiO[tex]_3[/tex]²⁻the oxidation state of Si is +4

Therefore, in above given ways we can assign oxidation state.

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The angle of insolation has the effect that the more the angle of insolation, the more the amount of heat absorbed by a material.

The impact of the insolation angle on the heat absorption rate of a substance  can be explained by the following factors that affect how much sunlight is absorbed on Earth's surface:

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Answer: B and E

Explanation: I just did it

Homologous structures are those that don't exactly appear alike or serve the same purpose but are structurally similar, indicating that they have a common ancestor. Examples of such structures are a bird's wing and a whale's flipper.

The arms of primates and bats are two common examples of homologous structures in evolutionary biology. Genetically, these two structures are related even though they do not share the same function or appearance as their most recent common ancestor.

Examples of homologous structures include the human arm, a bird or bat's wing, a dog's leg, a dolphin or whale's flipper, and a bird or a bat's wing. They are distinctive and possess despite having differing goals, they are comparable and possess similar qualities.

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