earth's atmosphere is approximately 78% nitrogen and 21% oxygen. what is the mass in grams of oxygen in a cubic meter of air in a typical classroom at 1 atm and 25C (1m^3=1000L)

Answer:

that one or more new substances are produced. Temperature Changes Chemical reactions can release energy or absorb energy.

Explanation:       .

Explanation:

alkalin metals is the first group in the periodic table

halogen is the 7 group in the periodic table

Explanation:

Since you're 16, you have to calculate how many seconds you've lived.

16 years × 31,536,000= 504,576,000 pennies.

504,576,000÷58 (for the amount of gold) = 8699586.2069 grams

Then go on from there. Hope that helped!

The values of X and Y in the diagram represent the progress of the reaction along the x-axis and the potential energy along the y-axis, respectively.

To determine whether the student's sketch of the potential energy diagram for an exothermic reaction is correct or incorrect, we need to understand the characteristics of such a reaction. In an exothermic reaction, the reactants have a higher energy level than the products, and energy is released during the reaction.The potential energy diagram should have the reactants positioned at a higher energy level (y-axis) than the products. As the reaction progresses from reactants to products, the potential energy should decrease, indicating the release of energy. This decrease in energy should be evident in the form of a downward slope or a curve.If the student's sketch accurately depicts these characteristics, with the reactants at a higher energy level than the products and a downward slope or curve indicating energy release, then the diagram is correct. However, if the student's sketch shows the reactants at a lower energy level or depicts an upward slope, it would be incorrect.The x-axis typically represents the reaction coordinate, which can be the extent of the reaction or the progression of time.

The y-axis represents the potential energy, which can be measured in joules or any other energy unit. The specific values on the axes will depend on the reaction and the units chosen.

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Approximately 4.37 x 10^23 molecules of HCl would be required to form 34.52 g of MgCl₂.

To determine the number of molecules of HCl required to form 34.52 g of MgCl₂, we need to use the molar mass and stoichiometry of the balanced equation:

Mg(OH)₂(s) + 2 HCl(aq) → 2 H₂O(l) + MgCl₂(aq)

The molar mass of MgCl₂ is 95.21 g/mol.

First, we need to calculate the number of moles of MgCl₂ formed:

Moles of MgCl₂ = mass of MgCl₂ / molar mass of MgCl₂

Moles of MgCl₂ = 34.52 g / 95.21 g/mol

Moles of MgCl₂ = 0.363 mol

According to the balanced equation, the stoichiometric ratio between HCl and MgCl₂ is 2:1. Therefore, the moles of HCl required can be calculated as follows:

Moles of HCl = 2 * Moles of MgCl₂

Moles of HCl = 2 * 0.363 mol

Moles of HCl = 0.726 mol

To calculate the number of molecules, we need to use Avogadro's number, which is approximately 6.022 x 10^23 molecules/mol.

Number of molecules of HCl = Moles of HCl * Avogadro's number

Number of molecules of HCl = 0.726 mol * 6.022 x 10^23 molecules/mol

Number of molecules of HCl = 4.37 x 10^23 molecules

Therefore, approximately 4.37 x 10^23 molecules of HCl would be required to form 34.52 g of MgCl₂.

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When dissolved in water, most Group 1 metal salts can be described as strong electrolytes.

When Group 1 metal salts are dissolved in water, they can be described as strong electrolytes. This is because Group 1 metals, such as lithium (Li), sodium (Na), potassium (K), and so on, readily lose their outermost valence electron to form positive ions (cations). These cations then dissociate completely in water, separating from the anions to which they were originally bonded.

The dissociation of Group 1 metal salts in water results in the formation of positively charged metal ions and negatively charged non-metal ions (anions). These ions are free to move and conduct electric current, making the solution a good conductor of electricity. The complete dissociation of Group 1 metal salts in water and the presence of freely moving ions make them strong electrolytes.

Strong electrolytes are substances that ionize completely or almost completely in solution, producing a high concentration of ions. This is in contrast to weak electrolytes, which only partially ionize and produce a lower concentration of ions.

In summary, when Group 1 metal salts are dissolved in water, they form strong electrolytes due to their ability to dissociate completely into ions, leading to a high concentration of freely moving ions in the solution, thus enabling efficient electrical conductivity.

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Answer:

Standard solution

Explanation:

The correct answer would be a standard solution.

By definition, a standard solution is a solution whose concentration is known and which is often used to determine the concentration of other substances in, for example, titration. The process of using a solution of known concentration to determine the concentration of another substance is known as standardization.

Based on the assumptions made about the type of car, the distance Honda Insight with EPA gas mileage rating of 57mi/gal will travel on 355 mL of gasoline is 8.6 km

The distance a car will travel on gasoline will depend on mileage rating of the car.

The units are converted to convert Km/mL as follows:

Then;

57 mi/gal = 57 × 1.609344 km/3785.411 mL

57 mi/gal = 0.0242 km/mL

Then;

Distance travelled on 355 mL = 0.0242 × 355

Distance travelled = 8.59 km

Therefore, the distance Honda Insight with EPA gas mileage rating of 57mi/gal will travel on 355 mL of gasoline is 8.6 km

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Answer:

1/2 of the Pi

Explanation:

PV = nRT

we are going to assume the only things changing are pressure and number of mols, so we change the formula and substitute the variables to make it what we are looking for

\(\frac{Pi}{ni} = \frac{Pf}{nf}\)

then we will assume Pi as 1 as it is not given, so we can state it easier

\(\frac{1atm}{10mol} = \frac{xatm}{5mol}\)

then either cross multiply or just work it out to be

\(\frac{1}{2}\) which we can say as "half of the initial pressure" as no number is given for initial pressure

Answer:

That one is tricky but i would say yellow

Explanation:

When hydrogen bromide (HBr) is added to 2-methylbut-2-ene ((CH3)2CCHCH3), an electrophilic addition reaction takes place, where the π bond of the alkene is broken, and the hydrogen and bromine atoms are added to the resulting carbocation.

The reaction proceeds through a Markovnikov addition, where the hydrogen atom attaches to the carbon atom with the greater number of hydrogen atoms.

In this case, the initial addition of HBr to 2-methylbut-2-ene leads to the formation of a primary carbocation, as the positively charged carbon atom only has one alkyl group attached to it. The primary carbocation is relatively unstable, and it can undergo a rearrangement to form a more stable secondary carbocation.

The major product that is typically obtained is the 2-bromo-2-methylbutane. The hydrogen atom from HBr adds to the carbon with three hydrogen atoms (the more substituted carbon), resulting in the formation of a secondary carbocation.

On the other hand, a minor product is also formed, which is 3-bromo-2-methylbutane. This product arises from the addition of HBr to the primary carbocation, which is less stable. Although the primary carbocation is less favored, it can still be formed and lead to the formation of the minor product.

In summary, the addition of HBr to 2-methylbut-2-ene yields two products: the major product is 2-bromo-2-methylbutane, resulting from the addition of HBr to the more stable secondary carbocation, and the minor product is 3-bromo-2-methylbutane, originating from the less stable primary carbocation.

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"Sam is being a good digital citizen by following a code of conduct.

A code of conduct is a set of rules that govern how people should behave online. It is important to follow a code of conduct because it helps to create a safe and respectful environment for everyone.

Here, Sam is following the code of conduct for his gaming group. This code of conduct may include rules about using offensive language, cheating, and griefing. By following these rules, Sam is helping to create a positive experience for everyone in his gaming group.

Therefore, Sam is following the code of conduct.

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Answer:

1.25 moles

Explanation:

You have 2.5 moles of Cl on product side and you need to make that equal on the reactant side. You can see it is Cl2  so you need to half 2.5 by 2 so both sides are equal. 2.5/2=1.25

The statement that is true regarding the solution prepared by adding 0.10 mol of potassium acetate to 1.00 L of water is that it is acidic (option B).

pH refers to the measure of the acidity or alkalinity of a solution. It can be calculated by using the following expression:

pH = - log {H}

Where;

The concentration of the acetate solution must first be calculated by dividing the number of moles by its volume as follows:

Molarity = no of moles ÷ volume

Molarity = 0.10 mol ÷ 1L = 0.1M

pH = - log {0.1}

pH = 1

1 indicates that the solution is acidic, hence, option B is correct.

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Answer:

we will except an increase in the polarity of the system and this will cause the Non-polar spot to be near the solvent front, while the polar spot will run at an approximate speed of 0.5 Rf

Explanation:

when we run a TLC plate in a 50/50 mixture of hexanes and ethyl acetate we will except an increase in the polarity of the system and this will cause the Non-polar spot to be near the solvent front, while the polar spot will run at an approximate speed of 0.5 Rf

The speed of the polar spot depends largely on the level of polarity, an increase in the polarity will see both spots of Neat hexane run when we run a TLC  plate in a 50/50 mixture of hexanes and ethyl acetate

Answer:

it's easy u just have to put them in a calculator the way they are it will give you your answer atleast I think so hope this helps

Answer:

4.8× 10²³ atoms

Explanation:

Given data:

Number of moles of San element = 0.796 mol

Number of atoms present = ?

Solution:

Avogadro number:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.  The number 6.022 × 10²³ is called Avogadro number.

1 mole = 6.022 × 10²³ atoms

0.796 mol ×  6.022 × 10²³ atoms / 1mol

4.8× 10²³ atoms

The molar mass of the sugar is obtained as  1.43 g/mol.

We know that the boiling point of a substance is one of the properties of the substances that could be called the colligative properties since they can be affected by the number of particles present.

We are told that the mass concentration of the substances w/w of the solution is 17% thus we have 17 g of the compound and 83 g of water. We can now get the number of moles of the substance as;

Number of moles = ?

Mass of the solution = 1000 mL * 1.015 g/mL = 1015 g or 1.015 Kg

Given that;

ΔT = K m i

ΔT = Boiling point elevation

K = Boing constant of water

m = molality of the solution

i = Van't Hoff factor

ΔT = 106 °C - 100°C

= 6 °C

Then;

6 = 0.515 *  17/MM * 1/1.015 * 1

Where MM = molar mass of the sugar

6 = 0.515 * 17/1.015 MM * 1

6 = 0.515 * 17/1.015 MM

6 = 8.755/1.015 MM

6 * 1.015 MM =  8.755

MM =  8.755/6 * 1.015

MM = 1.43 g/mol

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Answer:I'm going to give some fictitious values just so that we can get some perspective on the matter.

Let's say that the surface temperature of our sun is 10, the surface temp of the bigger star- the red giant formed from leaving the main sequence, has a temp of 0.2. of that- 2.

We can also say that the radius of our sun is 10, and the radius of the red giant is 1000. (100 times more)

Using the equation:

L

=

σ

A

T

4

σ

= The Stefan-Boltzmann constant =

5.67

×

10

−

8

But we can ignore the constant, as we are only interested in a ratio of these values.

L

S

u

n

=

4

π

(

10

)

2

×

10

4

=

1.26

×

10

7

L

S

t

a

r

=

4

π

(

1000

)

2

×

2

4

≈

2.01

×

10

8

2.01

×

10

8

1.26

×

10

8

≈

16

So the newly formed, red giant star is almost 16 times more luminous than the sun. This is owing to the increased surface area of the star due to the massively increased radius.

A small sidenote:

There is an equation that might be useful for comparing the radii, temperature and luminosity of main sequence stars. As red giants are not on the main sequence it could not be used here, but if you stumble across a question where they ask you to find the radius, luminosity or temperature given the other two, you can relate it to the sun's characteristics:

r

s

t

a

r

r

s

u

n

=

√

L

s

t

a

r

L

s

u

n

×

(

T

s

u

n

T

s

t

a

r

)

2

(I know, it's not a beauty to look at- but it works)

Where

X

s

u

n

is the radius, temperature, and luminosity of the sun. These are not often given in numerical values, but this equation serves well when asked to find e.g the radius of a star, in solar radii given that a star is twice as luminous and has 5 times the temperature of that of the sun.

Hence:

T

s

t

a

r

=

5

T

s

u

n

L

s

t

a

r

=

2

L

s

u

n

r

s

t

a

r

r

s

u

n

=

√

2

L

s

u

n

L

s

u

n

×

(

T

s

u

n

5

T

s

u

n

)

2

(cancel the common terms)

r

s

t

a

r

r

s

u

n

=

√

2

×

(

1

5

)

2

r

s

t

a

r

≈

0.057

r

s

u

n

(divide both sides by 0.0057)

17.5

r

s

t

a

r

≈

r

s

u

n

So the star's radius is almost 17.5 times that of the sun.

Hopefully, you find this info useful!

Explanation:

The water cycle iss a process which helps to circulate and replenish water on earth.

Hydrology is the scientific study of water bodies , the changes that occur in them as well as the various features and behavior of water bodies such as oceans and rivers.

Water circulation created by prevailing wind systems. The Gulf Stream is an example up of the Coriolis effect.

The length of open sea over which wind can blow steadily to create waves is called fetch.

Salinity is the amount of dissolved salt in a liquid

The distance from the crest of one wave to the crest of another is called wavelength

Water circulation created by differences in density deepwater currents

Energy is what moves forward and through a wave.

The cyclical process of the changing state and movement of water around the Earth through evaporation, condensation, and precipitation is called water cycle.

As the amount of salt in water increases, the density of the water increases.

The type of energy possessed by moving water is called kinetic energy.

The rising of ocean water bringing nutrients up from the deep us called upwelling.

Therefore, the water cycle helps to circulate and replenish water on earth.

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Answer:

1. 315.4 K

2. 1560 °C

Explanation:

To convert from celsius to Kelvin, the following formula can be used:

T(K) = T(°C) + 273

Where:

T(K) => Temperature in Kelvin

T(°C) => Temperature in degree celsius

1. Determination of the temperature in Kelvin.

Temperature (T) in °C = 42.4 °C.

Temperature (T) in K =?

T(K) = T(°C) + 273

T(K) = 42.4 °C + 273

T(K) = 315.4 K

2. Determination of the temperature in degree Celsius.

Temperature (T) in K = 1833 K

Temperature (T) in °C =?

T(K) = T(°C) + 273

1833 = T(°C) + 273

Collect like terms

T(°C) = 1833 – 273

T(°C) = 1560 °C

The Br are in 25 g CaBr2 will be approximately 203.87 g of Br.

The molar mass of an element's atoms is calculated by multiplying the element's comparative atomic mass by the molar mass constant.

In the given scenario, we need to find the grams of Br in CaBr2.

We know that,

molar mass of Br = 79.904 g/mol

molar mass of CaBr2 = 199.886 g/mol

CaBr2 = 2 Br + Ca

So, by the given data,

199.886 g = 2 x 79.904 g

255 g = X ( i.e., mass of Br )

X = 255 x 2 x 79.904 / 199.886

X = 203.87 g of Br

Thus, the amount of Br is 203.87gm.

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Explanation:

Boyle's Law

Answer:

160 g/mol

Explanation:

Step 1: Calculate the molarity of the solution

We will use the following expression.

π = M × R × T

where,

M = π / R × T

M = 1.84 atm / (0.0821 atm.L/mol.K) × 298 K = 0.0752 mol/L

Step 2: Calculate the moles of solute in 550 mL (0.550 L)

0.550 L × 0.0752 mol/L = 0.0413 mol

Step 3: Calculate the molecular weight of the nonelectrolyte

0.0413 moles weigh 6.60 g.

6.60 g/0.0413 mol = 160 g/mol

Answer:

143°C = 416K

306.178 liters is the volume of O2 at STP, required for the complete combustion of 125g octane (\(C_{8}H_{18}\)) to \(CO_{2}\) and H20

To calculate the volume of \(O_{2}\) required for the complete combustion of octane (\(C_{8}H_{18}\)) to \(CO_{2}\) and \(H_{2}O\) at STP (Standard Temperature and Pressure), we need to consider the stoichiometry of the balanced chemical equation.

The balanced equation for the combustion of octane is:

\(C_{8}H_{18}\) + 12.5\(O_{2}\) -> 8\(CO_{2}\) + 9\(H_{2}O\)

From the equation, we can see that 1 mole of octane requires 12.5 moles of \(O_{2}\) to completely combust. The molar mass of octane (\(C_{3}H_{18}\)) is approximately 114.22 g/mol.

To calculate the moles of octane, we divide the given mass by the molar mass:

Moles of octane = 125 g / 114.22 g/mol ≈ 1.093 mol

Since the molar ratio between octane and \(O_{2}\) is 1:12.5, the moles of \(O_{2}\)required can be calculated as:

Moles of \(O_{2}\) = 1.093 mol * 12.5 ≈ 13.663 mol

Now, we can use the ideal gas law, PV = nRT, to calculate the volume of \(O_{2}\) at STP. At STP, the temperature is 273 K, and the pressure is 1 atm.

Using the molar volume of an ideal gas at STP (22.4 L/mol), the volume of \(O_{2}\) required is:

Volume of \(O_{2}\) = Moles of \(O_{2}\) * Molar volume = 13.663 mol * 22.4 L/mol ≈ 306.178 L

Therefore, approximately 306.178 liters of \(O_{2}\) at STP would be required for the complete combustion of 125 grams of octane (\(C_{8}H_{18}\)) to \(CO_{2}\) and \(H_{2}O\)

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Answer:

the generation of electricity and other energy jointly, especially the utilization of the steam left over from electricity generation to produce heat.

I hope it helps!! Have a nice day

Answer:

Cogeneration r is the use of a heat engine or power station to generate electricity and useful heat at the same time.

Explanation:

We have to find the percent yield of the reaction, but we don't have the theoretical yield. To find it, we have to calculate the mass of aspirin that will be theoretically produced by 79.8 g of C₇H₆O₃.

First we have to convert 79.8 g of C₇H₆O₃ to moles using its molar mass.

molar mass of C = 12.01 g/mol

molar mass of H = 1.01 g/mol

molar mass of O = 16.00 g/mol

molar mass of C₇H₆O₃ = 7 * 12.01 g/mol + 6 * 1.01 g/mol + 3 * 16.00 g/mol

molar mass of C₇H₆O₃ = 138.13 g/mol

mass of C₇H₆O₃ = 79.8 g

moles of C₇H₆O₃ = 79.8 g * 1 mol/(138.13 g)

moles of C₇H₆O₃ = 0.578 moles

Now we can find the moles of aspirin produced by 0.578 moles of C₇H₆O₃.

C₇H₆O₃ (s) + C₄H₆O₃ (s) ---> C₉H₈O₄ (s) + HC₂H₃O₂ (aq)

According to the coefficients of the equation 1 mol of C₇H₆O₃ will produce 1 mol of aspirin.

1 mol of C₇H₆O₃ = 1 mol of C₉H₈O₄

moles of C₉H₈O₄ = 0.578 moles of C₇H₆O₃ * 1 mol C₉H₈O₄/(1 mol of C₇H₆O₃)

moles of C₉H₈O₄ = 0.578 moles

So we found that 79.8 g of C₇H₆O₃ will yield 0.578 moles of C₉H₈O₄. To get the theoretical yield we have to convert the moles into grams using the molar mass of C₉H₈O₄.

molar mass of C = 12.01 g/mol

molar mass of H = 1.01 g/mol

molar mass of O = 16.00 g/mol

molar mass of C₉H₈O₄ = 9 * 12.01 g/mol + 8 * 1.01 g/mol + 4 * 16.00 g/mol

molar mass of C₉H₈O₄ = 180.17 g/mol

mass of C₉H₈O₄ = 0.578 moles * 180.17 g/mol

mass of C₉H₈O₄ = 104.1 g = theoretical yield

Finally we can find the percent yield of the reaction.

actual yield = 65.9 g

percent yield = actual yield/theoretical yield * 100 %

percent yield = 65.9 g/(104.1 g) * 100 %

percent yield = 63.3 %

Answer: The percent yield of the reaction is 63.3 %.

Explanation:

A chemical bond is a lasting attraction between atoms, ions or molecules that enables the formation of chemical compounds.