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Answer:

2

Explanation:

Cells divide and reproduce in two ways, mitosis and meiosis. Mitosis results in two identical daughter cells, whereas meiosis results in four sex cells.

Answer: 67.4%

Explanation:

Ca 40.8

W. 183.8

O. 16.00

CaWO3 272.6

W = 183.8/272.6 = 0.674

67.4% percent by mass of tungsten in the calcium tungstate compound CaWO3, commonly called scheelite.

The 200 Speed Blue Emitting Calcium Tungstate Screen is the most commonly used Non-Rare Earth intensifying screen. With a faster speed than Detail or Medium speed screens, the Hi-Plus Intensifying Screen provides an efficient balance between the time patients are exposed during x-rays and image quality and detail.

It was also used in radium paint in the same fashion as was zinc sulfide, and Thomas Edison invented a fluoroscope with a calcium tungstate-coated screen, making the images six times brighter than those with barium platinocyanide; the latter chemical allowed Röntgen to discover X-rays in early November 1895.

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Answer:

C₂ =  0.52 M

Explanation:

Given data:

Initial volume = 334.75 mL

Initial concentration = 1.28 M

Final volume = 822.18 mL

Final concentration = ?

Solution:

C₁V ₁     =     C₂V₂

By putting values,

1.28 M×334.75 mL = C₂×822.18 mL

C₂ =  1.28 M×334.75 mL / 822.18 mL

C₂ =  428.48 M.mL / 822.18 mL

C₂ =  0.52 M

Answer:

I think it's B- it is transparent

Answer:A

Explanation:Glass can not be classified as a crystal when it is in its amorphous phase.

Answer:

9.64 x 10^22

Explanation:

To go from moles to molecules, you multiply by Avogadro's number, 6.022 x 10^23, so you get 9.64 x 10^22.

Answer:

The IUPAC name of the compound has already been given which is 2,2-dimethyl-4-ethylheptane.

Explanation:

The IUPAC (International Union of Pure and Applied Chemistry) is an authority in chemistry that provides a guideline and standardized methods in the naming of compounds formed from the periodic table.

In order the give an IUPAC name to a compound, certain steps needs to be followed, these includes:

--> Identify the functional group in the compound as this will form the suffix. For example if the functional group is an alkane the suffix will be -ane.

--> Identify the longest carbon chain (it may not be a straight chain) that contains the functional group. This forms the prefix. Example: if the longest carbon chain is 7 carbon atoms then the prefix will be hept-

--> All the carbons of the longest chain should be numbered

--> Identify branched groups on the chain and name them according to the number of carbon atoms. They usually end with -yl.

--> Finally, combine the elements of the name is a single word.

The structural formula of the IUPAC compound can be found in the attached file for a better understanding. The branched groups are circled.

Answer:

The Law of Conservation of Mass states that mass is neither created nor destroyed in chemical reactions. Since the number and type of atoms in the reactant side of the chemical equation are the same as on the product side, the Law of Conservation of Mass has been demonstrated.

Explanation:

In the answer.

The two main postulates that was given by Antoine Lavoisier are, oxygen play an important role in combustion and the other is mass of the reactant and product is conserved. Therefore, the given image is a good model for the Law of Conservation of Mass.

According to Law of conservation of mass, mass can neither be created nor be destroyed. Mass can only be transformed from one form to another. The law of conservation of mass was given by Antoine Lavoisier.

Every reaction in nature follow the law given by Antoine Lavoisier that is mass is always conserved. Another postulated that was given by Antoine Lavoisier is the role of oxygen in combustion reaction. Combustion can not happen without presence of oxygen.

The  image is a good model for the Law of Conservation of Mass as number and type of atoms on the reactant side and  product side are the same.

Therefore, the given image is a good model for the Law of Conservation of Mass.

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Answer:

Although he was unaware ofit, Mendeleev had actually placed the elements inorder of increasing “atomic number,” a numberrepresenting the amount of positively charged protons in the atom (also thenumber of negatively charged electronsthat orbit the atom). Mendeleev went even further.

Answer:

D. Uses sunlight to create glucose (sugar)

Explanation:

The function of the chloroplast is that it uses sunlight to create glucose.

The chloroplast allows for light to be trapped which is used for the synthesis of glucose from carbon dioxide and water.

The chloroplast is a rich in a pigment called the chlorophyll. This chlorophyll is a green pigment which allows for the trapping of solar energy

This solar energy is used to carryout the photosynthetic reaction.

Answer:

26g

Explanation:

Given parameters:

Density  = 8.96g/cm³

Volume of metal = 2.9mL

    Since 1mL  = 1cm³;

          Volume  = 2.9cm³  

Unknown:

Mass of the blocks in grams  = ?

Solution:

Density is the mass  per unit volume of a substance;

   Mass  = density x volume  = 8.96 x 2.9  = 26g

Answer:

software is a collection of codes installed onto your computer hard drive and hardware is any physical device that we used in or with your machine.

hope it helps.

Answer: soft water is water with a low concentration of ions and hard water is one with a high concentration of water e.g rainwater

Explanation:

answer:

In biology, the energy that is stored in the bonds between compounds is termed as the chemical energy. This chemical energy is released and converted into different forms according to the functions of the body.

Potential energy can be described as the energy that is stored in an object. In physics, the energy that an object possesses while at rest is termed as the potential energy.

The energy that can be used during work is termed as the kinetic energy. In physics, kinetic energy can be described as the energy that an object possesses while in motion.

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Answer: The stored energy is termed as potential energy while the working energy is termed as kinetic energy. The electricity used in our homes is also a form of energy because it is a form of usable power. The places from which the different energies are obtained are known as energy sources.

Answer:

halogen.

nonmetal.

Explanation:

Answer:

Ar

Explanation:

1s2|2s2 2p6|3s2 3p6 means 2+2+6+2+6=18 electrones. Also it means the number in the table.

According to the №18 the requested element is Argon.

The element argon with atomic number 18 is found to has the electronic configuration 1s² 2s² 2p⁶ 3s² 3p⁶. Here the element 'Ar' belongs to the 18th group of the periodic table.

The electronic configuration is defined as a method which represents the arrangement of electrons in the atomic orbitals. Each of the elements have a unique electronic configuration.

The physical, chemical and magnetic properties of the elements can be predicted by knowing their electronic configuration. Sometimes the term electron structure can also be used instead of electronic configuration.

The species K⁺ ion has the same electronic configuration of 'Ar'. The atomic number of 'K' is 19 and  K⁺ is formed by the lose of one electron from 'K'. Here  K⁺ has 18 electrons and its electronic configuration is:

1s² 2s² 2p⁶ 3s² 3p⁶.

Thus the element argon has the electronic configuration 1s² 2s² 2p⁶ 3s² 3p⁶.

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Answer:

C solution

Explanation:

i hope that i got it right im not very good with questions

Answer:

Copper does not reacts with dilute sulphuric acid, liberating hydrogen because copper is lower in the electromotive series than hydrogen. ... The metals above hydrogen in the activity series react with dilute sulphuric acid and dilute hydrochloric acid to liberate hydrogen.

The molecular formula : C₁₈H₁₈N₈

Given

62.41% C, 5.24% H, and 32.36% N

Required

The molecular formula

Solution

mol ratio

C : 62.41/12.0096 = 5.1967

H : 5.24/1.00784 = 5.1992

N : 32.36/14.0067 = 2.310

Divide by 2.310(smallest)

C : 5.1967/2.31=2.25

H : 5.1992/2.31 = 2.25

N : 2.31/2.31 = 1

Multiplied by 4

C : H : N = 9 : 9 : 4

The empirical formula : C₉H₉N₄

(C₉H₉N₄)n=346.40 g/mol

(12.0096 x 9 + 1.00784 x 9 + 14.0067 x 4)n=346.4

(108.0864+9.07056+56.0268)n=346.4

(173.184)n=346.4

n=2

The molecular formula : C₁₈H₁₈N₈

Answer:

Degree of hardness is defined as the number of parts of calcium carbonate or equivalent to various calcium and magnesium salts present in a million parts of water by mass.

Explanation:

General guidelines for classification of waters are: 0 to 60 mg/L (milligrams per liter) as calcium carbonate is classified as soft; 61 to 120 mg/L as moderately hard; 121 to 180 mg/L as hard; and more than 180 mg/L as very hard. Lime scale buildup inside a water pipe

Units:  mg/l  , ppm , kg/[tex]m^{3}[/tex]  , ppb , g/L

Answer: Pb(NO3)2(aq) + 2KI(aq)  —> PbI2(s) + 2KNO3(aq)

Explanation:

Answer:bro u already have an answer why are you asking?

Explanation:

Answer:

i think its oxide not too sure

Answer:  

 Its should be ammonium chloride.

A picture to help you with another question like this

Answer:

1. B 2. C 3. A

Explanation:

I just took it

Limiting reactant is the reactant the produces the least amount of the product.

In a chemical reaction, the reactant that is in least supply is the limiting reactant while the reactant that is more than required is the excess reactant.

To match each term with its description, we have;

the product

amount of the product

produced by the given reactants

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Answer:

6moles of Mg

Explanation:

The reaction expression is given as:

          BO₃   +    3Mg   →    3MgO    +    B

Given:

Number of moles of B produced  = 2 moles

Unknown:

Number of moles of Mg required  = ?

Solution:

  From the balanced reaction expression:

          1 mole of B is produced from 3 moles of Mg

          2 moles of B will be produced from 2 x 3  = 6moles of Mg

Moles of phosphoric acid would be needed : 0.833

Given

15 grams of water

Required

moles of phosphoric acid

Solution

Reaction(decomposition) :

H3PO4 -> H2O + HPO3

mol water (H2O :

= mass : MW

= 15 g : 18 g/mol

= 0.833

From the equation, mol ratio H3PO4 = mol H2O = 1 : 1, so mol H3PO4 = 0.833

Answer:

The true statement about semi-empirical methods is:

It combines a theoretically sound model of bonding with some experimentally determined parameters.

Explanation:

Semi-empirical methods are theoretical assumptions combined with experimental data to improve computational performance.  In modern computational chemistry, semi-empirical methods play important roles. The methods offer the advantage of a substantial reduction in computational time.  They also increase one's ability to carry out calculations for large molecules.  However, with these methods, there is the added loss of the variational principle because one can obtain a total energy that is below the true total energy.  Again, semi-empirical methods have limited applicability because the methods apply to molecules with parameterized elements.  Semi-empirical methods may supply spurious results, especially since the molecular systems may be different from those used for parameterizations.

Answer:

Yes, in both cases the reactant bond must be broken before the H can bond.

Explanation:

Let us remind ourselves of the basics of the collision theory. According to this theory, chemical reaction occurs because of the collision of particles of substances in a chemical reaction system.

This means that the bond between reactants must first be broken and new bonds formed in products. Activation energy is the minimum energy required for a reaction to occur. This energy goes into the rearrangement of reactant bonds to enable them to recombine and form products.

Since the N2 bond energy is far higher than the I2 bond energy, a greater degree of energy is needed overcome the energy barrier in the reaction of H2 with N2 compared to the reaction of H2 and I2 . Therefore, the activation energy for the reaction of H2 and N2 is much higher than the activation energy for the reaction of H2 with I2.

Answer:

th relative ability of a solute to devolve into a solvent

Answer:

Their must be a picture with this question so we can answer it

Explanation:

According to octet rule  the bonded valence shells are completely filled. All the compounds except the first one, CH₃CH₃O is invalid since H does not obey the rule and invalid.

Octet rule says that an atoms become stable when it completes its valence shell to 8 electrons or 2 electrons for K-shell. Thus bonded shells have to completely filled to be stable.

Each atom shares its electrons based on its valency. For example carbon have a valency of 4 and it forms for bonds and oxygen and sulfur have two and hydrogen forms only one bonds.

In the first compounds CH₃CH₃O, where one H forms two bonds which is not possible and invalid.

In the second compound CONH, all the atoms satisfies its valency including nitrogen having a valency of three forms  three bonds. Similarly in CH₂F₂, one fluorine forms one bond and the structure is valid.

In the case of Br₂ , each bromine shares one electron with the other and complete their octet to eight electrons. In NH₃, SCO and COCl₂ all the atoms satisfies their valency and the structures are valid.

Therefore the only invalid structure is first compound, remaining all are valid.

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