How to solve this problem? I am stuck

Answer:

5.1044844 x 10^7/cm^3 = 5E7

Explanation:

The atomic weight and density (at 25 ° C) for copper are 63.5 g/mol or 0.0635 kg/mol and 8,960 kg/m^3

First lets find the value of N, number of atomic sites per cubic meter for copper, from its atomic weight Acu, its density, and Avogadro’s number NA

N = NA x ρ / Acu = 6.023 x 10^23 x 8,960 kg/m^3 / 0.0635 kg/mol = 8.4985953 x 10^28 atoms / m3

Temperature dependency can be given as :

Arrhenius equation

Nv = N e^(-EA/KT)

N = no. of atoms initially

Ev = activation energy

Nv = 8.4985953 x 10^28 atoms / m^3 exp^-(0.9ev/atom /8.617x10-5 eV/(atom-K) x 298 K

Nv = 5.1044844 x 10^13 /m3

vacancies per cm^3 = 5.1044844 x 10^7/cm^3 = 5E7

Answer:

wings

Explanation:

this is an example of movement because it allows birds to fly in the air

Answer: There are 7.4 moles of helium gas present in a 1.85 liter container at the same temperature and pressure.

Explanation:

Given: [tex]V_{1}[/tex] = 2.25 L,     [tex]n_{1}[/tex] = 9.0 mol

[tex]V_{2}[/tex] = 1.85 L,            [tex]n_{2}[/tex] = ?

Formula used to calculate the moles of helium are as follows.

[tex]\frac{V_{1}}{n_{1}} = \frac{V_{2}}{n_{2}}\\[/tex]

Substitute the values into above formula as follows.

[tex]\frac{V_{1}}{n_{1}} = \frac{V_{2}}{n_{2}}\\\frac{2.25 L}{9.0 mol} = \frac{1.85 L}{n_{2}}\\n_{2} = \frac{1.85 L \times 9.0 mol}{2.25 L}\\= 7.4 mol[/tex]

Thus, we can conclude that there are 7.4 moles of helium gas present in a 1.85 liter container at the same temperature and pressure.

Answer:

1. 80.9 g of CH₃OH

2. CO

3. 5.14moles

Explanation:

The reaction is:

CO  +  2H₂  →  CH₃OH

First place, we determine the moles of each reactant.

70.8 g . 1mol/ 28g = 2.53 moles of CO

20.4 g . 1mol / 2g = 10.2 moles of H₂

There is too much hydrogen, so the limiting reactant might be the carbon monoxide.

2 moles of H₂ react to 1 mol of CO

Then, 10.2 moles of H₂ may react to (10.2 . 1) /2 = 5.1 moles

We don't have enough CO, so it's ok that CO is the limiting. (We have 2.53 moles, we need 5.1 moles)

In the other hand, hydrogen is the excess reactant.

1 mol of CO react to 2 moles of hydrogen

2.53 moles may react to (2.53 . 2) /1  =5.06 moles

We have 10.2 moles, and we need 5.06 moles. Then (10.2 - 5.06) = 5.14 moles remains after the reaction goes complete.

Now that we know the limiting reactant, we can determine the grams of produced methanol. Ratio is 1:1

1 mol of CO produces 1 mol of CH₃OH

2.53 moles of CO must produce 2.53 moles of CH₃OH

We convert moles to mass: 2.53 mol . 32 g/mol = 80.9 g

Answer:

Just use a text book.. So that you get the concept

Answer:

building amino acids in proteins

Explanation:

In order to react with 467.08 grams of O2, 4034.95 g of toluene (C6H5CH3) is required.

Toluene is a white liquid hydrocarbon found in petroleum and coal tar that is employed like a solvent and in the synthesis of organic compounds. Toluene is a naturally occurring substance found in crude oil and is used for oil refining as well as the production of glues, lacquers, paints, and explosives. Toluene can be discovered in household products like paint, paintbrush cleaner, nail polish, glue, inks, and stain removers.

For the balanced equation

2C6H5CH3 + 3O2 → 7CO2 + 4H2O

We required three steps

1.) Convert mass of O2 to mol of O2

mole = mass / molar mass

2.) Find mole of C6H5CH3 by multiply mol O2 by the mol ratio between O2 and C6H5CH3 in balanced equation.

3.) Find mass C6H5CH3 by multiply mol C6H5CH3 by its molar mass (92.14 g/mol)

= 467.08 gm /15.999 gm × 3/ 2 ×92.14 gm

= 4034.95 gm. of C6H5CH3

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The molecular weight of [tex](NH_4)_2SO_4[/tex] would be 132 g/mol.

The molecular weight, otherwise known as the molar mass of substances is the sum of the molar weights of individual atoms that make up the substance.

[tex](NH_4)_2SO_4[/tex] is made up of 2 atoms of N, 8 atoms of H, 1 atom of S, and 4 atoms of O.

Thus, the molecular weight of [tex](NH_4)_2SO_4[/tex] = (14x2) + (1x8) + 32 + (16x4)

                                                                     = 132 g/mol

In other words, the molecular weight of [tex](NH_4)_2SO_4[/tex] is 132 g/mol.

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The VSEPR drawing for the compounds in the question are shown in the images attached.

We have to know that according to the valence shell electron pair repulsion theory, the structure of the molecule can be found by looking at the number of electron pairs that surround the central atom in the molecule.

Now the structure of the compounds as we can see in the images that ahve been attached are based on the Vlence Shell electron pair repulsion drawing for each of the compounds that we have mentioned in the question.

We can see that the structure of the compound must have a central atom and then the other atoms in the molecule are arranged around the central atom of the molecule.

The molecule would have a definite shape that is based on the number of electron shells in the molecule.

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Answer:

.

Explanation:

a. 2, 2

b. 2, 2

c. 2, 3, 2

d. 1, 5, 3, 4

Just make sure there is an equal amount of each ELEMENT on each side of the reaction. Starting with, O, H, C, then other elements is a good method too

Answer:

True

Explanation:

It is TRUE that Phenylephrine is a nasal decongestant and is the active ingredient in Sudafed, which contains phenylephrine hydrochloride (PEHCl).

Phenylephrine is considered a prescription formula that is used in the production of Sudafed. Due to its direct-acting sympathomimetic amine property, it is used as a significant ingredient in the formation of Sudafed, a drug usually prescribed for nasal decongestion from regular cold, upper respiratory allergies, hay fever, etc.

Answer: The volume of oxygen at STP is needed for complete given combustion is 1121.28 L.

Explanation:

The given reaction equation is as follows.

[tex]2C_{2}H_{18}(l) + 25O_{2}(g) \rightarrow 16CO_{2}(g) + 18H_{2}O(g)[/tex]

This shows that 2 moles of gasoline requires 25 moles of . Hence, moles of oxygen required to react with 4 moles of gasoline are calculated as follows.

[tex]\frac{25 mol O_{2}}{2 mol C_{2}H_{18}} \times 4 mol C_{2}H_{18}\\= 50 mol O_{2}[/tex]

At STP, the pressure is 1 atm and temperature is 273.15 K. Therefore, using ideal gas equation the volume of oxygen is calculated.

PV = nRT

where,

P = pressure

V = volume

n = no. of moles

R = gas constant = 0.0821 L atm/mol K

T = temperature

Substitute the values into above formula as follows.

[tex]PV = nRT\\1 atm \times V = 50 mol \times 0.0821 L atm/mol K \times 273.15 K\\V = 1121.28 L[/tex]

Thus, we can conclude that volume of oxygen at STP is needed for complete given combustion is 1121.28 L.

Answer:

Explanation:

1) The following balanced chemical equations are for based on the combustions of various fuels. Calculate the heats of combustion for each reaction a. C₂H₂OH + ...

Answer:

3 (NH4)2SO4(aq) + 2 Al(NO3)3(aq) → 6 NH4NO3(aq) + Al2(SO4)3(aq)

Explanation:

In solubility rules, all ammonium and nitrates ions are solubles and all sulfates are soluble except the sulfates that are produced with Ca²⁺, Sr²⁺, Ba²⁺, Ag⁺ and Pb²⁺. That means the NH4NO3 and the Al2(SO4)3 produced are both soluble and no precipitate is predicted.

The reaction is:

Answer:

D

Explanation:

Silicon, element number 14 is the fourth element in the third period in the periodic table. Its electronic configuration is 1s^2 2s^2 2p^6 3s^2 3p^2.

The elemental symbol of the previous noble gas preceding the atom is replaced by the arrangement of the remaining electrons to form a noble gas configuration of an atom.

So for Silicon, we substitute [Ne] 1s^2 2s^2 2p^6 and the noble gas configuration can now be [Ne] 3s^2 3p^2.

The complete question is: [tex]CH_{4}(g) + O_{2}(g) \rightarrow CO_{2}(g) + H_{2}O(g)[/tex] balance?

Answer:  [tex]CH_{4}(g) + 2O_{2}(g) \rightarrow CO_{2}(g) + 2H_{2}O(g)[/tex] is a balanced equation.

Explanation:

A chemical equation which contains same number of atoms on both reactant and product side is called a balanced chemical equation.

For example, [tex]CH_{4}(g) + O_{2}(g) \rightarrow CO_{2}(g) + H_{2}O(g)[/tex]

Here, number of atoms on reactant side are as follows.

Number of atoms on product side are as follows.

To balance this equation multiply [tex]O_{2}[/tex] by 2 on reactant side and multiply [tex]H_{2}O[/tex] by 2 on product side. Hence, the equation can be re-written as follows.

[tex]CH_{4}(g) + 2O_{2} \rightleftharpoons CO_{2}(g) + 2H_{2}O(g)[/tex]

Here, number of atoms on reactant side are as follows.

Number of atoms on product side are as follows.

Since, there are same number of atoms on both reactant and product side. So, this equation is a balanced equation.

Thus, we can conclude that [tex]CH_{4}(g) + 2O_{2}(g) \rightarrow CO_{2}(g) + 2H_{2}O(g)[/tex] is a balanced equation.

Answer:

Just use a text book.. So that you get the concept

Hence, [tex]C_{20}H_{20}O_4[/tex] is the molecular formula of a compound's empirical formula is [tex]C_5H_5O[/tex].

The empirical formula is the chemical formula of a compound that gives the proportions (ratios) of the elements present in the compound but not the actual numbers or arrangement of atoms.

Divide the molar mass of the compound by the empirical formula mass. The result should be a whole number or very close to a whole number. Multiply all the subscripts in the empirical formula by the whole number

The molar mass of the empirical formula compound [tex]C_5H_5O[/tex] is 46.06844 g/mol.

The molecular mass of the compound is 162.2g given.

162.2g ÷ 46.06844

3.520848546 =4

[tex]C_{20}H_{20}O_4[/tex] is the molecular formula.

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Answer:

2.4.17892

Explanation:

34.1/816×100=4.17892

Answer:

polymer mear least receptive to dye

,

Answer:

The water will not interfere with the testing of flammable liquids.

When forensic scientists investigate this fire, the water will not interfere with the testing of flammable liquids. Therefore, option B is correct.

A flammable liquid is one with a flash point at or below the nominal threshold temperatures specified by a variety of national and worldwide standards organizations. This means that it can easily ignite in air at room temperature.

our home probably contains a sizable number of flammable liquids. Rubing alcohol, nail polish remover, hand sanitizer, and wart remover are some items that quickly catch fire in addition to gasoline and lighter fluid.

Gasoline is one of the most hazardous liquids in the home and causes over 8,000 home fires each year. One explanation is the frequent inappropriate storage of items in garages. Store it at room temperature, away from heat sources like your hot water heater or furnace, in a UL-approved container.

Thus, option B is correct.

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Answer:

2 N2O(g) + 3 O2(g) --> 4 NO2(g)

Explanation:

this is the chemical reaction balanced, if that was ur question.

Answer:

2K +F₂→ 2KF

Explanation:

When we balance an equation, we are trying to ensure that the number of atoms of each element is the same on both sides of the arrow.

On the left side of the arrow, there is 1 K atom and 2 F atoms. On the right, there is 1 K and 1 F atom.

Since the number of K atoms is currently balanced, balance the number of F atoms.

K +F₂→ 2KF

Now, that the number of F atoms is balanced on both sides, check if the number of K atoms are balanced.

Left

K atoms: 1

F atoms: 2

Right

K atoms: 2

F atoms: 2

The number of K atoms is not balanced.

2K +F₂→ 2KF

Left

K atoms: 2

F atoms: 2

Right

K atoms: 2

F atoms: 2

The equation is now balanced.

Polyatomic ions are ions made up of more than one atom.

What are Atoms?

Atoms are the smallest particles of matter that make up all objects. They are composed of protons, neutrons, and electrons. Protons and neutrons make up the nucleus of the atom, while electrons orbit around the nucleus. Atoms are the basic units of matter and are the building blocks of all living and nonliving things.

Polyatomic ions are ions that consist of two or more atoms covalently bonded together and carrying a net electric charge. Examples of polyatomic ions include nitrate (NO3−), sulfate (SO42−), phosphate (PO43−), and carbonate (CO32−).

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sorry needed the points

The mass of phosphorus in a 63 kg person would be 0.63 kg or 630 grams.

According to several research findings, the percentage of phosphorus in the human body is about 1%. This means that the weight of an average human is about 1% phosphorus.

Using the above information, the mass of phosphorus in a 63 kg person can be estimated as follows:

1/100 x 63 = 0.63 kg

Since 1 kg = 1000 grams

Thus, 0.63 kg = 0.63 x 1000

                       = 630 grams

In other words, the mass of phosphorus in a 63 kg person would be 0.63 kg or 630 grams.

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Answer:

Explanation:

In water, silver nitrate (AgNO3) dissolves to generate the ions Ag+ (silver) and NO3- (nitrate). When the substance is dissolved in water, the ions are separated and become solvated, or surrounded by water molecules. Water molecules' oxygen atoms join the metal ion in a coordinate covalent bond that gives the metal ion a pair of electrons. By preventing it from interacting with other ions or molecules in the solution, this aids in stabilising the metal ion. As a result of their hydrogen bonds with the water molecules around them, the nitrate ions are likewise stabilised in solution.

Answer:

this is a animal cell..I hope you received this on time

They are distinct Similarity: Compared to crustal rocks, mantle rocks have higher concentrations of magnesium and iron. The deep mantle's rocks are under extreme pressure and heat.

Earth's interior is made up primarily of the mantle, which is solid. Between the thin crust at the surface of the planet and its dense, extremely hot core is the mantle. A staggering 84% of the volume of the Earth is made up of the mantle, which is around 2,900 kilometers 1,802 miles thick.

The thickest layer on Earth measures just under 3,000 kilometers 1,865 miles. The beginning is only 18.6 miles 30 kilometers below the surface. It is thick, heated, and semi-solid like caramel candy, mostly made of iron, magnesium, and silicon. It circulates, much like the layer beneath it.

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