A controlled experiment _____.Group of answer choicesIs repeated many times to ensure that the results are accurateProceeds at a slow pace to guarantee that the scientist can carefully observe all reactions and process all experimental dataIncludes at least two groups, one of which does not receive the experimental treatmentIncludes at least two groups, one differing from the other by two or more variables

The composition of each compound as the mass percent of its elements is as follows:

Concentration is expressed as mass percent. Additionally, the ingredients in a particular mixture are described. Solution composition can be understood in terms of mass percent. It indicates the mass of solute present in a solution of a given mass. The amount of solute is expressed in mass or moles.

Mass Percent = (Component Mass ÷ Total Mass) x 100% or

(mass of solute ÷ mass of solution) x 100%

a. Sucrose (C₁₂H₂₂O₁₁) with molecular mass of 342.296 u composed of:

Carbon: (12 x 12.01) / 342.296 = 42.18%

Hydrogen: (22 x 1.01) / 342.296 = 6.44%

Oxygen: (11 x 16) / 342.296 = 51.38%

b. Aluminum sulfate (Al₂(SO₄)₃) with molecular mass of 342.14 u is composed of:

Aluminum: (2 x 26.98) / 342.14 = 3.99%

Sulfur: (3 x 32.06) / 342.14 = 4.57%

Oxygen: (18 x 16) / 342.14 = 87.44%

c. Magnetite (Fe₃O₄) with molecular mass of 231.534 u is composed of:

Iron: (3 x 55.85) / 231.534 = 71.83%

Oxygen: (4 x 16) / 231.534 = 28.17%

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The order of Sy2 reactivity for the sets of compounds you provided would be:

Compound B (H2C=CHCH2CI)

Compound C (CI)

Compound A (CI)

This is because Compound B has the greatest electron-donating ability due to the presence of the alkyl group attached to the carbon bearing the halogen, making it the most nucleophilic and therefore the most reactive in an Sy2 reaction. Compound C is less reactive than B because it lacks the electron-donating alkyl group, and Compound A is the least reactive due to the lack of electron-donating groups.The term "Sy2 reactivity" refers to the reactivity of a compound in a nucleophilic substitution reaction where the leaving group is displaced by a nucleophile. The abbreviation "Sy" stands for "substitution" and the subscript "2" indicates that the reaction is bimolecular, meaning that the rate of the reaction is dependent on the concentrations of both the substrate and the nucleophile.

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Density is an intensive property as it does not depend on the quantity of the substances Whereas mass and volume are extensive property. Therefore, the density of a rock with a volume of 6.7 mL and a mass of 12.34 grams is 1.841g/ml.

Density tells about the compactness of the substances, how much dense is the substances in other words. Object that is more denser than water they just sink in the water.

Mathematically,

Density of rock = Mass of the rock ÷volume marked on the graduated cylinder

volume of rock= 6.7 mL

mass of rock= 12.34 grams

Substituting all the values in above formula, we get

Density of rock=  12.34 grams÷6.7 mL

                           =1.841g/ml

Therefore, the density of a rock with a volume of 6.7 mL and a mass of 12.34 grams is 1.841g/ml.

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Because of its simplicity, comparatively low cost, great sensitivity, and rapid separation, TLC is an extensively used analytical method.

Using a thin stationary phase supported by an inert backing, thin layer chromatography (TLC) is a chromatographic technique used to separate the components of a mixture. It can be carried out on an analytical scale to track the development of a reaction or on a preparative scale to purify minute quantities of a chemical. Similar to all chromatography, TLC works on the premise that a chemical will have varying affinities for the mobile and stationary phases, which will influence how quickly it migrates. TLC aims to produce well-defined, well-separated spots.

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The electrons in the 2p sub level have the smallest binding energies, which is the best explanation for how the spectrum is consistent with the electron shell model of the atom. Option D is correct as a result.

Photoemission spectroscopy, often referred to as photoelectron spectroscopy, measures the amount of energy emitted by electrons from solids, gases, or liquids via the photoelectric effect. This procedure involves getting the energy for the electrons from an outside source, such as sunlight.

The photoelectric effect is a process in which electrons receive energy from an external source, such as sunlight, become excited, and transition from the ground state to the excited state. As a result of this process, there is a constant flow of electrons, which in turn causes a flow of energy.

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Decomposition of one mole of magnesium carbonate (84 g) produces one mole of magnesium oxide (40 g). Thus, 1280 g of magnesium carbonate will produce 609 g of MgO.

Magnesium carbonate is an ionic compound formed by donation of two electrons from magnesium metal to the carbonate group.

The decomposition reaction of magnesium carbonate is written below:

[tex]\rm MgCO_{3} \rightarrow MgO + CO_{2}[/tex]

As per this reaction, one mole of magnesium carbonate produces one mole of MgO.

molar mass of MgCO₃ = 84 g/mol

molar mass of MgO = 40 g/mol

84 g of  MgCO₃  gives 40 g of MgO. Then the mass of MgO produced by 1280 g of MgCO₃  is:

mass of MgO = (1280 × 40)/84 = 609 g.

Therefore, the mass of MgO produced is 609 g.

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The kind of molecular motion that mostly relates to temperature of a substance is : A) translational motion.

Motion in which all the points of a moving body moves uniformly in the same direction. If object is undergoing translatory motion, we can see that there is no change in the orientation of object. Translatory motion is also called translational motion.

In kinetic theory of gasses, increasing the temperature of a gas increases the average kinetic energy of the molecules, causing an increased motion. This increased motion increases outward pressure of the gas, which an expected result from the ideal gas equation (PV=NkT).

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The correct answer is option C: Low temperature only, because entropy decreases during freezing.

When a substance changes from a gas to a solid, the entropy (measure of disorder) of the system decreases. This is because the solid has a more ordered structure than the gas. The decrease in entropy is accompanied by a decrease in temperature and an increase in enthalpy (heat content).For a process to be spontaneous, the entropy change must be positive, so the freezing of methane is spontaneous only if the temperature of the surroundings is lower than the temperature of the methane. Thus, the heat released from the exothermic process will be absorbed by the surroundings, the temperature of the methane will decrease, and the entropy of the system increases, driving the process towards completion.

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The complete question is :

Methane freezing is an exothermic process. Which of the following best describes the temperature conditions that are most likely to cause this spontaneous change? Because entropy increases during freezing, any temperature. Because entropy decreases during freezing, any temperature. Only at low temperatures because entropy decreases during freezing. Only at high temperatures, as entropy

In the given question,It will take Caroline 1.2 hours  to travel 45 miles if she is traveling 37 mph (miles per hour).

As we know the velocity formula:

v = d/t

Where

V is velocity, d is distance and t is time.

as given in the question

distance = 45 miles

velocity = 37 mph

To find time t,

put the values in the formula:

t = d/v

t = 45/37

t = 1.2 hours

It will take Caroline 1.2 hours  to travel 45 miles if she is traveling 37 mph (miles per hour).

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Answer:

hi, I haven't done this in a while, but I think this is it!

Explanation:

20

8 Iron Atoms

12 Oxygen Atoms

Elements of group 18 belongs to the family of noble gases with a general electronic configuration ns²np⁶,  where the valence shell is completely filled.

The elements of group 18 are considered to be noble because they have a completely filled valence shell due to which they donot have the tendency to gain, lose or share their valence electrons with other atoms. Thus, they are highly unreactive.

The elements belonging to noble gas family are:  Helium (He), Neon (Ne), Argon(Ar), Krypton(Kr), Xenon(Xe), Radon(Rn).

under conditions of standard pressure and temperature, these elements exists as gases with very low chemical reactivity so they are known as inert gases.

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The simplest formula for a compound is made up of 1.677 grams of iron and 0.640 grams of oxygen would be FeO.

What the question is asking here is the empirical formula of an oxide of iron made up of 1.677 grams of iron and 0.640 grams of oxygen. The empirical formula shows the formula in the simplest whole-number ratio of the atoms.

Iron (Fe) = 1.677 grams

Oxygen (O) = 0.640 grams

Converting the masses to moles:

Fe = 1.677/56 = 0.0299 mol

O = 0.640/16 = 0.0400 mol

Now, let's divide by the smallest mole:

Fe = 0.0299/0.0299 = 1.0

O = 0.0400/0.0299 = 1.3

Thus, the empirical formula of the oxide of iron is FeO.

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The reason behind the acceptance of Darwin's theory is D It is supported by practical evidence and examples.

The theory of evolution proposed by Charles Darwin is a well sustained model that explains how animals change in order to adapt to an ever-changing enviroment, which is supported by scientific evidence and observations.

Therefore, with this data, we can see that the theory of evolution proposed by Charles Darwin is well sustained by evidence obtained from experimentation and also observations of the natural world.

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Orbitals that are described by each of the combinations quantum numbers ; n = 3, ℓ =2 orbitals n = 4, ℓ = 2 is 5. ml=2 here is referring to last(5th) orbital space 4d.

In atomic theory and quantum mechanics, atomic orbital is a function describing the location and wave-like behavior of electron in an atom.

Quantum numbers  (n, l, ml, ms )

n=3, refers to 3rd energy level      

3rd energy level has 3 possible values of l  and d has 5 different orientations.

s=0   p=1    d=2

--> -2,-1,0,1,2

When; n=3 l=2, then number of orbitals is 5.

n=4 refers to 4th energy level ;        

4th level has 4 possible l values;      

s=0 p=1 d=2 f=3        

When, n=4   l=2 and  ml=2  

The number of orbitals is 5 and  ml=2 is referring to last(5th) orbital space 4d.

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0.0450 moles of calcium chloride are contained in this sample

A mole of every substance weighs the same as its molecular mass and contains the same number of particles, according to Avogadro's law.

Utilizing the equation, we can determine the moles.

Number of moles=  Given Mass/ Molar Mass

Number of Moles = [tex]5.00 mg / 110.98 g/mol = 0.0450 moles[/tex]

Thus there are 0.0450 moles of [tex]Cacl2[/tex]

The mole is the volume of a substance that contains exactly as many molecules, atoms, radicals, ions, or electrons as there are in 12 grams of 12C.

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As a result of photosynthesis the level of CO₂ decrease and the the level of o2 increase in the environment.

Photosynthesis is a chemical process that occurs in algae, plants and some types of bacteria, when they are exposed to the sunlight. During photosynthesis, water and carbon dioxide will combine to form carbohydrates and gives off oxygen.

During photosynthesis, plants take carbon dioxide from the air. Within the plant cell carbon dioxide is reduced, meaning it gains electrons. This transforms the carbon dioxide into glucose. The plant then releases the oxygen back into the air, and stores energy within the glucose molecules.

Photosynthesis increases the content of the non-structural carbohydrates in the leaves which can lead to grater starch reserves and increased auxin biosynthesis.

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Lone electron pairs are absent from the Be atom. A negative formal charge would be placed on the Be atom as a result of the double bonds existing between it and the Cl atom.

When compared to an isolated neutral atom, the number of electrons that are attached to an atom in a molecule determines its formal charge.

The octet rule is broken by B e C l 2, as the boron should be in a valence state that enables it to attach to three chlorines. However, in this molecule, the boron is joined by six electrons.

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A fossil that has 6.25% of its carbon atoms is still unstable.

Carbon-14 dating is a method of determining the age of organic material. Measures the amount of carbon-14 (a radioactive isotope of carbon) present in the sample. The half-life of carbon-14 is 5,730 years. This means that after 5,730 years, half of the carbon-14 atoms in the sample have decayed to nitrogen.

If 6.25% of the fossil carbon atoms are unstable, this means that 93.75% of the carbon-14 atoms in the sample have already decayed. To determine the age of a fossil, the following formula can be used:

Age = (half-life x ln(1-(fraction of decayed carbon-14/100))) / ln(2)

Age = ( 5,730 x ln(1 - (93.75/100))) / ln(2)

age = 11,460 years old

c. A fossil in which 75% of the atoms are STABLE.

If 75% of the fossil atoms are STABLE, this means that 25% of the carbon-14 atoms in the sample have decayed. The same formula as above can be used to determine the fossil age. 75 )) / ln(2)

Age = 23,120 years

Please note that these are approximate values, as the actual age of the fossils may be affected by various factors such as contamination, preservation, and measurement error.

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To determine the value of Kp for a reaction, we need to know the concentrations of all the reactants and products at equilibrium.

In this case, we are not given the equilibrium concentrations, so we cannot directly calculate Kp. Instead, we can use the ideal gas law to relate the equilibrium concentrations to the partial pressures of the gases, and use those partial pressures to calculate Kp.The equation for the ideal gas law is PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature. If we assume that the reaction occurs at a constant volume and a constant temperature, we can use the ideal gas law to relate the equilibrium partial pressures of the gases to the concentrations of the gases.Given that we have no information about the equilibrium concentrations or partial pressures, we can not calculate Kp.

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A gas mixture containing oxygen, nitrogen, and He has a total pressure of 189.9 kPa. If PO2 = 104.6 kPa and PN2 = 13.0 kPa, PHe is 72.3 kPa.

Static pressure and velocity pressure are added to create total pressure. There is static pressure in a fluid that is not flowing. The pressure required to accelerate air from a zero velocity to a specific velocity that is proportional to the kinetic energy of the air stream is known as velocity pressure.

Consider the friction that exists between a fluid and the interior surface of a pipe. The fluid's density and velocity are used to compute the dynamic pressure: the total pressure in a mixture of ideal gases is the total of the partial pressures of the individual gases.

Total pressure = PO2  + PN2 + PHe

189.9 kPa = 104.6 kPa + 13.0 kPa + PHe

PHe = 72.3 kPa

Thus, A gas mixture containing oxygen, nitrogen, and He has a total pressure of 189.9 kPa. If PO2 = 104.6 kPa and PN2 = 13.0 kPa,PHe is  72.3 kPa.

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The limiting reactant is O2.

To determine the limiting reactant, we need to compare the number of moles of each reactant present.

First, we convert the given masses of phosphorus and oxygen to moles:

25.0 g of P4 = 25.0 g / (123.8 g/mol) = 0.202 mol

50.0 g of O2 = 50.0 g / (32.00 g/mol) = 1.5625 mol

Next, we use the balanced equation for the reaction to determine the stoichiometry of each reactant:

P4 + 5O2 → P4O10

From the equation, we can see that for every one mole of P4, 5 moles of O2 are required.

We can then compare the number of moles of each reactant present:

0.202 mol P4 / 1 mol P4 = 0.202

1.5625 mol O2 / 5 mol O2 = 0.3125

We can see that the number of moles of O2 is less than the number of moles of P4 required by the reaction, so the limiting reactant is O2.

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Laboratories are used in many different fields, including medicine, chemistry, biology, physics, engineering, and more.

A laboratory is a facility where scientists conduct research and experiments. It is equipped with specialized equipment, tools, and supplies required for the specific purpose of conducting scientific tests, experiments, and analysis.

The next step would be to look for other seminal components, such as white blood cells, red blood cells, epithelial cells, and other organic and inorganic components. If no sperm are present, then a detailed analysis of the sample is necessary to determine the cause of the absence of sperm. Possible causes of azoospermia, or the absence of sperm, include hormonal imbalance, anatomical defects, genetic conditions, and medical treatments.

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According to the given chemical equation and stoichiometry of it , 36 moles of H₃PO₄ are formed from 9 moles of P₄O₁₀.

It is the determination of proportions of elements or compounds in a chemical reaction. The related relations are based on law of conservation of mass and law of combining weights and volumes.

Stoichiometry is used in quantitative analysis for measuring concentrations of substances present in the sample.

As per the reaction, 1 mole of P₄O₁₀ produces 4 moles of  H₃PO₄, thus 9 moles of  P₄O₁₀ will produce 9×4=36 moles of H₃PO₄.

Thus,36 moles of H₃PO₄ are formed from 9 moles of P₄O₁₀.

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Answer:36

Explanation:

taking the class just got it right

The remaining reactant (Aluminum Hydroxide) weighs approximately 11.73 g.

Hence, Option A is correct.

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The space left by the free electron in an atom after it has lost one electron is known as a hole.

The term "free electron" refers to an electron that has broken loose from its "parent" atom and is now free to move about the material at random. A vacancy, also known as a hole, is created in the atom when a bonded electron in a lattice atom breaks free. The number of electrons in an atom's valence shell, or n shell in this example, has a significant impact on the electrical properties of the element that the atom represents. The least force of attraction is felt by the electrons in the valence shell since they are the furthest from their nucleus.

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The number of moles of oxygen a worm absorbs per hour can be calculated using the formula:

A = (LR^2dO2) / (MT)

Where A is the molar flow rate of oxygen, L is the length of the worm, R is the radius of the worm, d is the density of the worm, O2 is the concentration of oxygen in the environment, M is the molar mass of oxygen, and T is the time in hours.

The number of moles of oxygen the worm uses per hour can be calculated using the formula:

B = (k*A)

Where B is the molar flow rate of oxygen used by the worm and k is the rate constant for oxygen consumption.

To determine whether the worm is taking in oxygen at a rate fast enough to survive, we would need to compare the rate of oxygen absorption (A) to the rate of oxygen consumption (B). If A > B, then the worm is absorbing oxygen at a rate that is greater than or equal to the rate at which it is consuming oxygen, and it should be able to survive. If A < B, then the worm is not absorbing oxygen fast enough to sustain its metabolism and it may not survive.

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Answer:275.4 g Al2O3

Explanation: The mass of Al2O3 formed is 2.7 mol * 102 g/mol = 275.4 g. This is because the molar mass of Al2O3 is 102 g/mol. This means that when 1 mol of Al2O3 is formed, it has a mass of 102 g. Therefore, when 2.7 mol of Al2O3 is formed, it has a mass of 2.7 mol * 102 g/mol = 275.4 g.

1 mole of any substance contains 6.023 × 10²³ particles. Therefore, 48.184 particles represents 8.0 moles.

The term mole is defined as the amount of substance in a system which include as many elementary entities as there are atoms present in it. It is denoted by the symbol “mol”. The word mole is coming from the Latin word moles, which means “a mass”.

The mole is also defined as it contain exactly 6.023 × 10²³ elementary entities present in it. 1 mole is exactly equal to the 6.023 × 10²³ elementary entities.

1 mole =  6.023 × 10²³

8 mole = 8 × 6.023 × 10²³

= 48.184 particles

Thus, 1 mole of any substance contains 6.023 × 10²³ particles. Therefore, 48.184 particles represents 8.0 moles.

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The estimated time of death is approximately 10:30 pm the night before.

Estimating the time of death (TOD) can be a complex process, and the methods used will depend on the specific circumstances of the case. Some of the factors that may be taken into consideration include:

It is important to note that estimating the TOD is not an exact science and there are often significant margins of error. A professional forensic examination is typically needed to determine the TOD.

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Hello there!

Answer:

A. <

Explanation:

You should remember that all negative numbers are smaller then positive numbers. For example, -10 < 7 or -9479 < 1

-4 is a negative integer

0.598 is a positive number

So -4 < 0.598 (negative < positive)