If the same test, given at different points in time to the same test takers, yields different scores, then the method typically used to assess this source of error is_________.

The mole fraction of LiBr is 0.8946

We are aware that the mole fraction or molar fraction is defined as the amount of a constituent (expressed in moles), ni, divided by the total amount of all the elements in the mixture (also indicated in moles, ntotal).

mole fraction = n/n overall

first we should calculate hw many gram the solution from the density

assume the volume is 1 L

so.

density = mass solution/ volume solvent

0.826 g/ml = mass/ 100mL

mass= 82.6 g

so the mole of the solution is

mole = mass/ mass molar

mole solution = 82.6 g / 41.05g/ mole = 2.012 mole

Then we can find the mole of LiBr from the concentration

molar= moles x volume

1.8 M = moles x 1 L

moles LiBr = 1.8 moles

thus,

mole fraction = n/ n total

mole fraction = 1.8/  2.012 =  0.8946

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Isopentane, commonly known as methyl butane or 2-methylbutane, is an alkane with a branched chain and five carbon atoms. Its chemical formula is C 5H 12 or CH(CH).

At normal temperature and pressure, isopentane is a highly flammable and volatile liquid. Additionally, under normal circumstances, it is the least dense liquid. [Reference needed] Isopentane has a standard boiling point that is only a few degrees above room temperature, therefore on a warm day, it will easily boil and evaporate. To achieve a liquid bath temperature of 160 °C, isopentane and liquid nitrogen are frequently utilized. Isopentane is a substantial component of natural gasoline, however, it normally only makes up 1% or less of natural gas.

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The frequency of radiation with a wavelength of 492 nm is

6.09 x 10^14 Hz.

What is the meaning of frequency of radiation of wavelength?

Frequency of radiation of wavelength is a measure of how often a particular wavelength of radiation occurs. It is measured in Hertz (Hz) and is equal to the number of wave cycles per second. Wavelength is the distance from one wave crest to the next, so frequency is related to the speed of the wave. A higher frequency corresponds to a shorter wavelength, and a lower frequency corresponds to a longer wavelength.

λ= 480nm =480×10−9m       [∵1nm=10−9m]

c=3×108m/sec

Frequency, v=λ/c

       =[tex]\frac{3*10^{8}ms^{-1} }{480*10^{-9}m }[/tex]

      = [tex]6.09*10^{14}s^{-1}[/tex]

       =[tex]6.09*10^{14} Hz.[/tex]

Therefore, 6.09 x 10^14 Hz is the answer.

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Answer:

C. T shaped

Explanation:

had this last year

The shape of XeF3+ is T-shaped. Therefore, option C is correct.

The three-dimensional configuration of the atoms that make up a molecule is known as molecular geometry. It provides data on the molecule's overall shape as well as bond lengths, bond angles, torsional angles, and any other geometrical aspects that affect each atom's location.

The structure that results has a Y-shaped geometry and an electrical structure of b22 a10. The T-shaped and Y-shaped structures of XeF3- are therefore a Jahn-Teller pair of states deriving from the identical D3h ion, as can be shown by this molecular orbital image.

The geometry of XeF3+ is T-shaped because the centre atom, Xe, is surrounded by 3 bond pairs and 2 lone pairs.

Thus, option C is correct.

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By changing gear and according to the brakes applied to the car.

Acceleration is the rate of change of the velocity of an object with respect to time.

There are three types of accelerated motions such as :

Therefore, In a car you could accelerate by hitting the gas or the brakes either of which would cause a change in speed. But you could also use the steering wheel to turn which would change your direction of motion. The car moves faster and faster, speed is the rate of change of position while acceleration is the rate of change of velocity.

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Answer:

Explanation:

Structure of 3-ethyl-5-isobutylnonane

It is given in the following attachment:

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The organic compound 3-ethyl- 5-isobutylnonane contains 9 carbon atoms in the long chain and one ethyl branch at the third carbon atom and one isobutyl group in the 5th carbon atom as in the image.

Hydrocarbons are organic compounds with carbon -hydrogen bonds. The organic compounds are named based on the rules of IUPAC. The compound gets its basic name from the number of carbon atoms in the longest chain.

If the number of carbons atoms is one, the chain is given its suffix meth, eth for two prop for three and so on. The chain with 9 carbon atoms are named with nonane in the end.

Here, the given compound contains an ethyl group as a branch in third carbon in the chain and an isobutyl group in the 5th position as shown in the image given below:

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The molarity when 24 grams of LiOH is added to 200 ml of water is 4.2M.

The moles of solute per liter of solution is measured as molarity. For instance, when table salt is dissolved in water, water serves as both the solution and the solute. Sodium chloride weights 58.44 grammes per mole. One molar solution, or 1M, is created by dissolving 58.44 grammes of sodium chloride in one liter of water.

The term "total moles of a solute contained in a kilogram of a solvent" is used to describe molality. Molal concentration is another name for molality. It is a measurement of a solution's solute concentration.

The molarity of the given LiOH solution is found to be 1.99 mol/L or 1.99M.

Given weight = 20g

molar mass of lithium hydroxide = 7+16+1=24g

volume = 200ml = 0.2l

Number of mole (n) = given weight /molar mass of lithium hydroxide

n = 20/24 =0.84

Molality = Number of mole (n) /volume of solvent

molality = 0.84/0.2

= 4.2M

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Yes, it is the right response. Although the elements are imaginary, they resemble actual elements .Nomenclature is an organism name system used in biological classification.

The Latin words nomen (name) and calare (to call) are the source of the word nomenclature. Both the Latin word nomenclatura and the English word nomenclator, which also denotes a source or broadcaster of names, relate to a list of names.

Nomenclature is an organism name system used in biological classification. Genus & species names, two Latinized nouns drawn from numerous sources, serve as indicators of the species whereby the creature belongs.

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B. Br-

Ionic radius is a way of measuring the size of an element or compound.

Ionic Radius

Ionic radius is defined as the distance between the nucleus of an atom and the outermost electron. In terms of the periodic table, ionic radius grows to the left and down. The largest element on the periodic table is Francium since it is the lowest element on the left side.

Effective Nuclear Charge

The ionic radius of cations (positive ions) is always smaller than the regular element. Also, the ionic radius of anions (negative ions) is always larger. This is due to effective nuclear charge. Effective nuclear charge is how attracted electrons are to the nucleus. As electrons are added, effective nuclear charge decreases as the shielding effect becomes larger. Additionally, as the negative charge increases, the positive charge has less pull. The opposite is true for cations.

Since the electrons are less attracted to the nucleus in anions, they spread out more. This causes the radius to increase. For this reason, Br- has the largest ionic radius out of the listed options.

As nac2h3o2(s) is stirred into water and dissolves, the electrical conductivity of the solution remains the same.

The ability of an aqueous solution to convey an electrical current is gauged by its conductivity. Since ions are responsible for carrying the current, the conductivity rises as ion concentration, mobility, and water temperature rise in a solution. Ionic strength is connected to conductivity measurements. But this isn't a qualitative experiment (that is, it is not known which ions are present). The electrical calculation for resistance, which is stated in, is the opposite of conductivity

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Materials such as concrete, bricks and tiles absorbs and store more heat as compared to materials such as timber and cloth which have low thermal masses.

Thermal mass in floors is most effective. In most of the climate conditions a concrete slab which is insulated underneath and around the edge and where it is in direct contact with the ground absorbs more energy and thus it is the most effective way to increase thermal mass.

Thermal mass refer to the property of construction materials to absorb, store, and release heat energy.

Water also have high thermal mass.

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As an animal grows, its mass increases. The matter that makes up this new mass comes mostly from the food  that the animal consumes.

Matter in chemistry, is defined as any kind of substance that has mass and occupies space that means it has volume .Matter is composed up of atoms which may or not be of same type.

Atoms are further made up of sub atomic particles which are the protons ,neutrons and the electrons .The matter can exist in various states such as solids, liquids and gases depending on the conditions of temperature and pressure.

The states of matter are inter convertible into each other by changing the parameters of temperature and pressure.

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Because it is structured in a repeating pattern, the crystal of strontium chloride (SrCl2) is referred to as having an extended structure.

A group of atoms or molecules that are present in a repeating pattern and are arranged in a specific ratio are said to produce extended structures in crystals. Crystals are composed of clustered together atoms of a single element or, in some cases, molecules.

We can infer that the strontium chloride (SrCl2) crystal is regarded as an extended structure because of its organization in a repeating pattern because of its repeating pattern and constant ratio of strontium chloride (SrCl2).

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Doses of gamma rays, X-rays of electromagnetic radiation and beta particles are measured with simple piece of equipment.

The electromagnetic radiation consists of waves made up of electromagnetic field which are capable of propogating through space and carry the radiant electromagnetic energy.

The radiation are composed of electromagnetic waves which are synchronized oscillations of electric and magnetic fields . They are created due to change which is periodic in electric as well as magnetic fields.

In vacuum ,all the electromagnetic waves travel at the same speed that is with the speed of air.The position of an electromagnetic wave in an electromagnetic spectrum is characterized by it's frequency or wavelength.They are emitted by electrically charged particles which undergo acceleration and subsequently interact with other charged particles.

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There are 4 valence electrons in an atom of C and 6 valence electrons in an atom of S. So, there is a total of 10 valence electrons in the CS molecule (6+4=10).

So, the carbon and sulfur form a triple bond in this compound so as to complete the octet of both C and S in the CS molecule. Also, there is an electron pair on both C and S.

Formal charge = valence electrons - (number of bond pairs + number of electrons present as lone pair)

The formal charge on C = 4 - (3 + 2) = 4 - 5 = -1

The formal charge on S = 6 - (3 + 2) = 6 - 5 = +1

The Lewis structure of the CS molecule is shown below:

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Since there are 6.022 1023 molecules in 1 mole of oxygen (O2), it has a mass of 32 grams.

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The amount of negative charge in one mole of oxygen gas, [tex]O_{2}[/tex] is 9.647 x [tex]10^{14}[/tex] coulomb.

One mole of oxygen gas, with the formula O2, weighs 32 g and includes 6.02 x [tex]10^{23}[/tex] molecules of oxygen, but also contains 12.04 x [tex]10^{23}[/tex] (2 x 6.02 x [tex]10^{23}[/tex]) atoms of oxygen, since each molecule of oxygen contains two oxygen atoms.

Since there are 6.022 1023 molecules in 1 mole of oxygen ([tex]O_{2}[/tex]), it has a mass of 32 grams. One mole of oxygen weighs 15.998 grams, whereas one mole of hydrogen weighs 1.008 grams. Since there are 6.022 1023 molecules in 1 mole of oxygen ([tex]O_{2}[/tex]), it has a mass of 32 grams.      

Mass of 1 mole of electrons:

9.10 x [tex]10^{13}[/tex] × 6.023× [tex]10^{23}[/tex] 5.486× [tex]10^{-7}[/tex] kg

Charge of 1 mole of electrons:

1.602× [tex]10^{-19}[/tex] × 6.023× [tex]10^{23}[/tex] = 9.647× [tex]10^{4}[/tex] coulomb

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Fossil fuels may cause water pollution because they release toxicants into the atmosphere, which is formed by air and water.

The relationship between fossil fuels and water pollution is based on the fact that fossil fuels are burned to release energy which may generate contamination that affects water into the atmosphere.

Therefore, with this data, we can see that the relationship between fossil fuels and water pollution is based on the release of toxic substances and greenhouse gases during this process that affects water in the atmosphere.

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Answer: F

Explanation:

When 445 kilograms of water are reacted, 102.94 or 103 grams of MnO2 mass are formed.

A bodily lump is referred to in medicine. It could be brought on by an immunological response, a cyst, hormonal abnormalities, or aberrant cell growth. A mass could either be benign (not cancerous) or malignant (cancer).

Simply said, mass is a method of determining that however much material seems to be present in something like a body. Matter is anything with both weight and volume.

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Answer: 4,300 g

Explanation:

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The compounds can be distinguished via UV spectroscopy by measuring their value.1,3-pentadiene is a type of conjugated compound while 1,4-pentadiene is not conjugated.

This causes the of 1,3-pentadiene to be higher than 1,4-pentadiene allowing us to distinguish between both. Using UV spectroscopy we measure the quantity or amount of light being absorbed by the sample and compare the obtained values. Thus, 1,3-pentadiene and 1,4-pentadiene can be distinguished by comparing their values obtained by UV spectroscopy.

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This transition has a lower energy for conjugated systems like 1,3-cyclohexadiene. Since this transition has a greater energy for unconjugated systems like 1,4-cyclohexadiene, the wavelength is typically too short to be visible.

cyclohexadiene diols are excellent starting materials for the synthesis of complex natural compounds due to their inherent benefits. For the synthesis of polyhydroxylated targets such inositols, cyclitols, and carbohydrates, the diol moiety is the ideal place to start. The chemical compound cyclohexa-1,3-diene has the formula (C2H4)(CH)4. It is a flammable, colourless liquid. It has a 20 °C, D, refractive index of 1.475. Terpinene, a substance found in pine oil, is a 1,3-cyclohexadiene derivative that occurs naturally. Cyclohexane, which has the chemical formula C6H12 and is planar and cyclic, lacks delocalized pi electrons (since there are no pi bonds), and it also does not abide by Huckel's rule. As a result, it lacks fragrance.

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Answer:

A

Explanation:

That one doesn't fall in the category of carbon cycle. It has nothing to do with natural causes since it is a man made thing. Industrial activities is not a natural cause.

Answer:

This answer makes an assumption noted in the Explanation.

1.772 moles of NO2

Explanation:

The balanced equation tells us that NO2 does not react with N2O5.  As written, the answer to the question is zero.

If the question is how many moles of NO2 are produced by 0.8861 moles of N2O5, then we can note that the equation promises us 4 moles NO2 per 2 moles N2O5.  That's a molar ratio of 4:2 (moles NO2/moles N2O5).

(0.8861 moles N2O5)*(4:2 (moles NO2/moles N2O5)) = 1.772 moles of NO2

Answer:

To determine the limiting reactant, you need to compare the amount of each reactant with the amount required to react completely with the other reactant. The reactant that runs out first is the limiting reactant.

In this case, the balanced equation for the reaction between MgSO4 and NH3 is:

MgSO4 + 2 NH3 → Mg(NH2)2SO4

From the balanced equation, we can see that 1 mole of MgSO4 reacts with 2 moles of NH3. Therefore, 3.7 moles of MgSO4 will react with (3.7 moles)(2 moles NH3/1 mole MgSO4) = 7.4 moles of NH3.

4.8 moles of NH3 is less than 7.4 moles, so NH3 is the limiting reactant.

Uday Tahlan

Answer:

Yes

Explanation:

Yes, I do think they mean the same thing. Explanation: 150 grams and 150 grams are the same thing and adding 0 to the end of a decimal

Matter are anything that is made up of atoms. The quantity of matter can be observed only on the basis of mass and volume calculation. Therefore, 150grams and 150.0 grams are the same measurement.

Matter is a substance that has some mass and can occupy some volume. The matter is mainly used in science. Matter can be solid, liquid or gas.

Matter is anything that is made up of atoms. Anything around us that can be physically seen and touched are matter. Ice, water and water vapors are example of matter.

Mass can also be represented as number of molecules. We also saw that matter occupy some volume and that volume is measured only in liter. 150 grams and 150.0 grams are the same measurement as both have same measurement.

Therefore, 50 grams and 150.0 grams are the same measurement.

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Answer:

14.5 moles of CH4

Explanation:

There is 14.5 moles of carbon in the product CO2....there has to be 14.5 moles of carbon in the reactant CH4

   14.5 moles

This is possible because the volume of water displaced by an object is determined by the volume of the object, not its weight or mass.

The cube of metal I and the cube of another metal both have the same volume, so they would displace the same volume of water. The principle of buoyancy states that the buoyant force on an object is equal to the weight of the fluid that is displaced by the object can be applied in here. Therefore, if two objects have the same volume, they will displace the same amount of fluid and experience the same buoyant force.

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Water is absorbed by CaCl2 molecules, resulting in bigger molecules. In order for the solute to dissolve in the solvent, the solute-solute interactions between the solute particles must be disrupted.

An inorganic material is calcium chloride, a salt with the chemical formula CaCl2. It is a white, crystalline substance that is highly water soluble at ambient temperature. It may be created by neutralizing calcium hydroxide with hydrochloric acid. By reducing the freezing point of water, calcium chloride is used to both prevent the production of ice and to remove it. This application makes the maximum use of calcium chloride.

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The correct answer is option d. The common name for (CH3)2CHCH2Cl is Iso-butyl chloride.

Iso-butyl chloride is a chlorinated derivative of isobutane. It is organochlorine compounds.  Isobutyl chloride is made up of compounds of chlorine, carbon, and hydrogen.

Other important details about Iso-butyl chloride is as following-

Formula: C4H9Cl

Boiling point: 69 °C

Molar mass: 92.57 g/mol

Density: 877 mg mL−1

Melting point: −131 °C (−204 °F; 142 K)

Heat capacity (C): 158.6 J K−1 mol−1

Refractive index (nD): 1.398

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The correct answer is 107.9 g of Ag is produced from a reaction of 31. 75 gram of Copper.

Molar mass of a substance is the mass in grams of one mole of the compound. A mole is the measurement of the number of things, such as atoms, molecules, and ions, that are present in a substance. Any material has 6.022 x 1023 molecules in a mole, it is known as Avogadro's number . The mole is used to determine the size of the tiniest entities quantitatively, just as we use a standard value to quantify many things, such as 1 dozen = 12 items.

Formula - Molar mass = mass in grams/mole = g/mol

Molar mass of a substance can be calculated as:

Given,

n = W/M, where

W = required mass

M= molar mas

Given chemical reaction is:

Cu + 2AgNO₃ → Cu(NO₃)₂ + 2Ag

From the stoichiometry of the reaction,

1 mole of Cu = produce 2 moles of Ag

Given mass of Cu = 31.75g

Molar mass of Cu = 63.5g/mol

Moles of Cu = 31.75g / 63.5g/mol = 0.5 moles

0.5 moles of Cu = produce 2×0.5 = 1 mole of Ag

Molar mass of Ag = 107.9g/mol

Required mass of Ag = 1mol × 107.9g/mol = 107.9 g

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Answer: divide the falling number and then get it

Explanation: find the answer