2. Why do you think electroplated jewelleries are in demand?
Chemistry plsss

Answer:

sorry i dont know

Explanation:

Air resistance opposes the gravity in a falling object hence the object loses speed once it reaches terminal velocity.

According to the experiment of Galileo, in the absence of air resistance, all objects that are thrown down from the same height will hit the ground at he same time due to the effect of gravity.

We know that the air resistance makes the acceleration of object to become less than the acceleration due to gravity. So, air resistance opposes the force of gravity and causes falling objects to lose speed once they reach terminal velocity.

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Answer:

The answer is D - Air resistance opposes the force of gravity and causes falling objects to lose speed once they reach terminal velocity.

Ill explain why -, for example ,

When the paper is smooth, it exposes a large surface to the air beneath it which slows its descent. Once it is crumpled, the surface which comes in contact with the air is much smaller, allowing it to fall much faster.  At first, you probably thought the book would touch the ground first since it is heavier However, once the piece of paper was crumpled, they hit the ground at the same time! Funny, since it is the same piece of paper and the book is still heavier. It all comes down to form. I hope this helped u with the test !!

Answer:

Explanation:

Thin-layer chromatography (TLC) is a chromatography technique used to separate non-volatile mixtures. ... After the sample has been applied on the plate, a solvent or solvent mixture (known as the mobile phase) is drawn up the plate via capillary action.

Answer:

1 kg = 1000 g

58.6=58,600g

Explanation:

Answer:

i can't understand the question

Answer:

Explanation:

Rutherford proposed the nuclear model of atom. The only one model which can be inferred from this model is nucleus with protons and revolving electrons around.

Rutherford proposed some aspects of atomic structure based on his gold foil experiment. He discovered that the alpha ray is scattering from foil by the repulsion it experienced from the metal.

This results lead to the discovery of positively charged particles in atom latter called as protons. Rutherford proposed that theses protons are located inside the nucleus and the electrons are revolving around the nucleus.

Latter Niels Bohr his student interpreted the nuclear model of Rutherford with quantum mechanics and theory of max planck and he proposed the equations for the determination of energy and momentum of electrons and the radius of atom.

Therefore, no other inferences except the presence of protons and revolving electrons can be obtained from Rutherford's model of atom.

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Answer:

44

Explanation:

This  problem provides the molar mass and radius of a metal that has an BCC unit cell and the density is required.

Firstly, we consider the formula that relates molar mass and also includes the Avogadro's number and the volume of the unit cell:

[tex]\rho =\frac{Z*M}{V*N_A}[/tex]

Whereas Z stands for the number of atoms in the unit cell, M the molar mass, V the volume and NA the Avogadro's number. Next, since BCC is able to hold 2 atoms and M and NA are given, we calculate the volume of the atom in the unit cell given the radius in meters:

[tex]V=a^3=(\frac{4R}{\sqrt{3} } )^3=(\frac{4*1.74x10^{-10}m}{\sqrt{3} } )^3=6.49x10^{-29}m^3[/tex]

And finally the required density in g/cm³:

[tex]\rho =\frac{2*341.1g/mol}{6.49x10^{-29}m^3\frac{m^3}{atom} *6.022x10^{23}\frac{atom}{mol} } =17455257.8g/m^3\\\\\rho=17.5g/cm^3[/tex]

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Waste is removed from the body in various ways. Kidneys filter out metabolic waste, excess fluid and eliminate it in the form of urine. Lungs exhale CO2 from the deoxygenated blood. The undigested solid waste is egested out from the large intestine. Excretion is the process of removing wastes and excess water from the body. It is one of the major ways the body maintains homeostasis. Organs of excretion make up the excretory system. They include the kidneys, large intestine, liver, skin, and lungs.

Answer:It goes through chemical reactions with oxygen, which forms new molecules and provides energy for cells.

Answer:

the answer is D) 23 carbon atoms, 34 hydrogen atoms, and 2 oxygen atoms

Explanation:

i took the test and got a 100%

Answer:

The answer is A and C.

Explanation:

The reactants in the process of cellular respiration are oxygen and glucose, respectively. It is ATP that serves as the primary product of cellular respiration, with carbon dioxide and water serving as waste products.

Sugar is a glucose.

Oxygen and glucose are the two  substances that are reactants in the chemical reactions of cellular respiration. Therefore, the correct options are options A, C.

Through the process of cellular respiration, organisms mix oxygen with food molecules, directing the chemical energy contained in these substances towards life-sustaining processes while excreting carbon dioxide and water as waste. Foods are broken down by microorganisms that do not require oxygen in a process known as fermentation.

Adenosine triphosphate (ATP), an energy-rich compound that absorbs the chemical energy generated by the decomposition of food molecules then releases it to power other cellular functions, is one goal of the breakdown of foodstuffs. ATP is created when the energy found inside chemical bonds is converted from one form to another. Oxygen and glucose are the two  substances that are reactants in the chemical reactions of cellular respiration.

Therefore, the correct options are options A, C.

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Considering the definition of percentage by mass and molality, the molality of Na₃PO₄ in the solution is 0.948 [tex]\frac{moles}{kg}[/tex].

The percentage by mass expresses the concentration and indicates the amount of mass of solute present in 100 grams of solution.

In other words, the percentage by mass of a component of the solution is defined as the ratio of the mass of the solute to the mass of the solution, expressed as a percentage.

The percentage by mass is calculated as the mass of the solute divided by the mass of the solution, the result of which is multiplied by 100 to give a percentage. This is:

[tex]percentage by mass=\frac{mass of solute}{mass of solution}x100[/tex]

Molality is the ratio of the number of moles of any dissolved solute to kilograms of solvent.

The Molality of a solution is determined by the expression:

[tex]molality=\frac{number of moles of solute}{kilograms of solvent}[/tex]

Considering 100 grams as a sample of the solution, then the value of the percentage of concentration given indicates that  13.5 g correspond to Na₃PO₄.

Remember that percent concentration by mass is calculated using the mass of solute and the mass of the solution, which includes both the solute and the solvent. Then:

mass solution= mass solute + mass solvent

100 g= 13.5 g + mass solvent

100 g - 13.5 g= mass solvent

86.5 g= mass solvent

Then, you know:

Then, replacing in the definition of molality:

[tex]molality=\frac{0.082 moles}{0.0865 kg}[/tex]

Solving:

molality= 0.948 [tex]\frac{moles}{kg}[/tex]

Finally, the molality of Na₃PO₄ in the solution is 0.948 [tex]\frac{moles}{kg}[/tex].

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Prior to writing the chemical formula of magnesium chloride, a question which any student will need to ask is: A.  What are the oxidation numbers of each atom?

A chemical formula can be defined as a scientific notation that is used to show (represent) the type and total number of atoms that constitute a particular chemical molecule or compound, by using the oxidation number, chemical symbols and subscripts.

Hence, a student would need to know the oxidation numbers of each atom when magnesium chloride is formed after a chemical reaction.

In Chemistry, an oxidation number represents the number of electrons gained or lost by an atom of a chemical element during a chemical reaction.

In conclusion, when magnesium chloride is formed, a question which the student will need to ask prior to writing the chemical formula is "what are the oxidation numbers of each atom?"

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Explanation:

83.6-24.2= 59.4 which is the change in heat

The amount of the sample remaining at 4pm is 0.0625 g

We'll begin by calculating the number of half-lives that has elapsed

Half-life (t½) = 1 hour

Time (t) = 4 hour

n = t / t½

n = 4 / 1

Number of half-lives (n) = 4

Initial amount (N₀) = 1 g

[tex]N = \frac{N_0}{ {2}^{n}} \\ \\ N = \frac{1}{ {2}^{4}} \\ \\ N = \frac{1}{16} \\ \\ N = 0.0625 \: g[/tex]

Thus, the amount remaining at 4pm is 0.0625 g

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Answer:

this the partial removal of a substance from a solution or mixture by dissolving it in another immiscible solvent in which it is more soluble.

Answer:

go get the stuff.

Explanation:

Answer:

im pretty sure its 2.7 gms

Explanation:

im not for sure tho

From the information provided in the question, the second ionization energy of the metal is  578 kJ/mol.

From the question, we have the following information;

Lattice enthalpy of MO(s) = -2383 kJ/mol

Bond dissociation enthalpy of O2(g) = +498 kJ/mol

First electron affinity of O = -141 kJ/mol

Second electron affinity of O = +744 kJ/mol

First ionization energy of M = + 267 kJ/mol

Heat of sublimation of M = + 130 kJ/mol

Standard enthalpy of formation of MO(s) = -307 kJ/mol

Using Hess law of constant heat summation;

ΔHf = ΔHs + BE + ∑IE + ∑EA + U

ΔHs  = Heat of sublimation of metal

ΔHf = Heat of formation MO

BE = Bond energy of O2

∑EA  = sum of electron affinities of Oxygen

∑IE  = Sum of the ionization energies of M

U = Lattice energy of MO

Let the second ionization energy be x

Substituting values;

(-307) = 130 + 498 + (267 + x) + 603 + (-2383)

(-307) = -885 + x

-x =   -885 + 307

-x = -578

x = 578 kJ/mol

The second ionization energy of the metal is  578 kJ/mol.

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According to the equation given, we have N2 + 3H2 → 2NH3.

Therefore, to determine the moles of NH3 we have to do the following-

1.3 mol H2 × 2 mol NH3 / 3 mol H2 = 0.87 mol

Answer: .87 moles of NH3 are produced from 1.3 moles of H2.

I hope this helps!

Answer:

HCl (hydrochloric acid) and H2SO4 (sulphuric acid)

I hope it helps.

Answer:

310K

Explanation:

Rearrange PV=nRT to get T=PV/nR

T=(2.0L)(0.75atm)/(0.5mol)(0.08206)

=36.5 or 37

add 273 for K to get

310

Answer:

Atoms themselves do not have a smell. Molecules do.

Explanation:

What happens is that particular molecules bind to receptors in our nose, activating nerves, that then send signals to our brain, which we then interpret and perceive as “smells”. Different molecules bind to different receptors, which is why we can perceive a number of different smells

Answer:

a. the breaking of bonds

Answer:

B

Explanation:

Hey, I am almost positive that the answer to this question is B. The breaking of bonds uses the energy but when they are created it releases energy. I hope this helps, Have a good day!

Answer:

Neon 10,  mass: 20.18

Explanation:

Answer:

Initial rate experiments

The simplest initial rate experiments involve measuring the time taken for some recognizable event to happen early in a reaction. This could be the time required for 5 cm3 of gas to be produced, for a small, measurable amount of precipitate to form, or for a dramatic color change to occur. Examples of these three indicators are discussed below.

The concentration of one of the components of the reaction could be changed, holding everything else constant: the concentrations of other reactants, the total volume of the solution and the temperature. The time required for the event to occur is then measured. This process is repeated for a range of concentrations of the substance of interest. A reasonably wide range of concentrations must be measured.This process could be repeated by altering a different property.

Explanation:

I don't think so if this is the answer. if not ok sorry

In this case, according to the given information about the oxidation numbers and the compounds given, it turns out possible to figure out the oxidation number of manganese in both MnI2, manganese (II) iodide and MnO2, manganese (IV) oxide, by using the concept of charge balance.

Thus, we can define the oxidation state of iodine and oxygen as -1 and -2, respectively, since the former needs one electron to complete the octet and the latter, two of them.

Next, we can write the following [tex]x[/tex], since manganese has five oxidation states, and it is necessary to calculate the appropriate ones:

[tex]Mn^xI_2^-\\\\Mn ^xO_2^{-2}[/tex]

Next, we multiply each anion's oxidation number by the subscript, to obtain the following:

[tex]Mn^xI_2^-\rightarrow x-2=0;x=+2\\\\Mn ^xO_2^{-2}\rightarrow x-4=0;x=+4[/tex]

Thus, the correct choice is Manganese has an oxidation number of +2 in Mnl2 and +4 in MnO2.

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