Complete the sentence

The Earth’s earliest atmosphere contained large amounts of carbon dioxide. The percentage of carbon dioxide in the Earth’s atmosphere today is ___

A) Less than 1%
B) 5%
C) 21%
D) 78%

Answer: A volume of 1.16 L hydrogen is produced at a pressure of 2 atm and a temperature of 298 K.

Explanation:

Given: Mass of Mg = 2.3 g

Pressure = 2 atm

Temperature = 298 K

The reaction equation is as follows.

[tex]Mg + 2HCl \rightarrow MgCl_{2} + H_{2}[/tex]

This shows that 1 mole of Mg gives 1 mole of [tex]H_{2}[/tex].

Hence, moles of Mg for the given mass is calculated as follows.

[tex]Moles = \frac{mass}{molar mass}\\= \frac{2.3 g}{24.30 g/mol}\\= 0.095 mol[/tex]

Hence, 0.095 moles of Mg will give 0.095 moles of [tex]H_{2}[/tex].

Formula used to calculate volume is as follows.

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 the above formula as follows.

[tex]PV = nRT\\2 atm \times V = 0.095 mol \times 0.0821 L atm/mol K \times 298 K\\V = \frac{0.095 mol \times 0.0821 L atm/mol K \times 298 K}{2 atm}\\= 1.16 L[/tex]

Thus, we can conclude that a volume of 1.16 L hydrogen is produced at a pressure of 2 atm and a temperature of 298 K.

Answer:

a. H + d. Na

Explanation:

This is Mixture of H and Na. Because of H and in the emission and Absorption spectrum of H Total 5 lines [Red, Green, Blue and Purple (2)) are present and in the spectrum of Na Two yellow lines are present. In the mixture all this lines are are also 5 + Present. Total lines are 5+2= 7 (H+ Na)

Therefore, the answer is a. H + d. Na

[tex]\huge\fcolorbox{red}{pink}{Answer ♥}[/tex]

The carbon atom is unique among elements in its tendency to form extensive networks of covalent bonds not only with other elements but also with itself. ... Moreover, of all the elements in the second row, carbon has the maximum number of outer shell electrons (four) capable of forming covalent bonds.

Hope it helps uh ✌️✌️✌️

Gud mrng

Answer: b and d

Explanation:

1×10^-3=1×1/10³=1×1/1000=1/1000 so b is correct

1×10^-3=1/1000=0.001

so d is correct

Answer:

Balancing equations

1

[tex]4Na + O_{2} -> 2Na_{2}O[/tex]

Answer:

Scientific Method

Explanation:

Science is empirical in nature. The entire purpose of science is to discover new knowledge.

The empirical research method in science all begins with gathering observations from phenomena. After that, the researcher formulates appropriate hypothesis which are rigorously tested.

The conclusions drawn from testing the original hypothesis validate or modify the original hypothesis.

Answer: A mass of 84.46 g of cesium fluoride would be required to make 73.1 g of cesium xenon heptafluoride.

Explanation:

Given: Mass of cesium xenon heptafluoride = 73.1 g

The molar mass of cesium xenon heptafluoride is 131.3 g/mol. So, moles of [tex]CsXeF_{7}[/tex] is calculated as follows.

[tex]Moles = \frac{mass}{molar mass}\\= \frac{73.1 g}{131.3 g/mol}\\= 0.556 mol[/tex]

According to the given equation, 1 mole of CsF yields 1 mole of [tex]CsXeF_{7}[/tex].

Hence, moles of CsF reacting will also be equal to 0.556 mol. As molar mass of CsF is 151.9 g/mol so its mass is calculated as follows.

[tex]Moles = \frac{mass}{molarmass}\\0.556 mol = \frac{mass}{151.9 g/mol}\\mass = 84.46 g[/tex]

Thus, we can conclude that a mass of 84.46 g of cesium fluoride would be required to make 73.1 g of cesium xenon heptafluoride.

1. Sodium triphosphate ·

2. Sodium hydroxide ·

3. potassium hydroxide

4. Sodium Lauryl Sulfate · 5.Hydroxyethylcellulose ·

6. Sodium carbonate

Explanation:

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'」*とまっぉのもヴぉこぉぞぽ、こ、

Answer:

Ca(OH)2 + 2NH4Cl .................. CaCl2 + 2NH3 + 2H2O

Answer:

See explanation

Explanation:

The structure of ethylene is shown in the image attached. The two carbon atoms have a double covalent bond between them.

The two carbon atoms are sp2 hybridized. The bond between them is a covalent bond, there is one pi bond and one sigma bond between the carbon atoms. Between carbon and hydrogen, there are covalent bonds also. The covalent bonds are sigma bonds.

The pi bonds between carbon atoms is weaker than the sigma bonds between the carbon atoms. This is because, the side-by-side overlap the p orbitals in a pi bond is less effective than the end-to-end overlap of a sigma bond.

Answer:

Concentric circles

Explanation:

The energy levels are shown as concentric circles around the central nucleus, and the electrons are placed from the inside out. The first two electrons are found in the first energy level, and the third electron is found in the second energy level.

Answer:

D Period 1, Group 18

Explanation:

it's helium

it's top right corner of the periodic table

Answer:

What period is the atom in?

1.

What group is the atom in?

What is the name of this atom?

What other atom would have similar

properties to the atom?

Will this atom conduct electricity well

Explanation:

How many of each kind of atom is in one molecule of water? 1 hydrogen atom and 2 oxygen atoms 1 hydrogen atom and 1 oxygen atom 2 hydrogen atoms and 1 oxygen atom 2 hydrogen

and 2 oxygen atoms

Answer:

When the two atoms are in contact, potassium readily transfers its outer electron to chlorine which readily accepts it, resulting in both atoms achieving a state of eight outermost electrons. With this electron transfer, the ionic bond in KCl is formed.

Answer:

Answer to the following question is as follows.

Explanation:

Acid rain causes harm to houses and buildings by dissolving stone or corroding metal exposed to the elements. Acid rain can degrade calcium carbonate or calcium-based chemicals found in some of these products.

The acidic particles damage metal and accelerate the deterioration of paint and stone. They also make buildings and other structures, like as monuments, filthy.

Answer: Here are the answers

Explanation:

7a) Calcium Chloride +water+carbon dioxide

b)Calcium Oxide +Carbon dioxide

8a) zinc + carbon monoxide

b) Aluminum + Carbon dioxide

c) Lead + carbon dioxide

Answer: A hygroscopic substance is one that readily attracts water from its surroundings, through either absorption or adsorption

Explanation:

Fluorine (F) and iodine(I) are the halogen elements that belong to group 17. They differ from each other as fluorine has 3 fewer energy shells than iodine. Thus, option D is correct.

Halogen is a nonmetallic element that belongs to group 17 and consists of six elements namely fluorine, bromine, tennessine, chlorine, astatine, and iodine.

They are diatomic and have 7 valence electrons in the outer shell, which makes them highly reactive and electronegative. The shielding effect is less in F than I due to the closer placement and attraction of the valence electron to the nucleus.

Fluorine differs from iodine as it has a smaller size with fewer energy shells than iodine. Iodine has five energy shells,  whereas fluorine has two energy shells that make the difference of three shells between them.

Therefore, F and I differ from each other.

Learn more about fluorine and iodine here:

https://brainly.com/question/2005537

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Answer:

27.9 g

Explanation:

CsF + XeF₆ → CsXeF₇

First we convert 73.1 g of cesium xenon heptafluoride (CsXeF₇) into moles, using its molar mass:

As 1 mol of cesium fluoride (CsF) produces 1 mol of CsXeF₇, in order to produce 0.184 moles of CsXeF₇ we would need 0.184 moles of CsF.

Now we convert 0.184 moles of CsF to moles, using the molar mass of CsF:

Answer:

2 Al + 3 Pb(NO3)2 > 2 Al(NO3)3 + 3 Pb

Explanation:

Answer:

1.78 mol

Explanation:

Step 1: Write the balanced equation

CaC₂ + H₂O ⇒ C₂H₂ + CaO

Step 2: Calculate the moles corresponding to 46.3 g of C₂H₂

The molar mass of C₂H₂ is 26.04 g/mol.

46.3 g × 1 mol/26.04 g = 1.78 mol

Step 3: Calculate the moles of H₂O required to form 1.78 moles of C₂H₂.

The molar ratio of H₂O to C₂H₂ is 1:1. The moles of H₂O required are 1/1 × 1.78 mol = 1.78 mol.

Answer:

18,9g de hexano son necesarios

Explanation:

Basados en la ley de Raoult, la presión de vapor ejercida por una solución es:

P = P°*Xsolvente

Donde P es la presión de la solución deseada = 700mmHg, P° la presión de vapor de vapor del benceno = 1atm = 760mmHg y X es la fracción molar del solvente (Benceno).

Reemplazando:

700mm Hg = 760mmHg * X(Benceno)

0.9211 = X(Benceno)

La fracción molar de benceno se define como:

X = Moles benceno / Moles benceno + Moles hexano

Moles benceno -Masa molar: 78g/mol-

200g * (1mol/78g) = 2.5641 moles benceno

X = Moles benceno / Moles benceno + Moles hexano

0.9211 = 2.5641 moles benceno / 2.5641 moles benceno + Moles hexano

0.9211moles Hexano + 2.3618 = 2.5641

0.9211*Moles Hexano = 0.2023

Moles hexano = 0.2023/0.9211 = 0.2196 moles hexano.

Masa Hexano -Masa molar: 86g/mol-

0.2196 moles hexano * (86g/mol) =

La cantidad de hexano (C6H14) que se debe agregar a 200 g de benceno para permitir que la presión de vapor se convierta en 700 mm de Hg sería:

18.9 g

Usando la ley de Raoult, la presión de vapor que libera una solución se encuentra por:

P = P ° × X disolvente  

Donde (P) denota la presión de la solución deseada

P ° denota la presión de vapor del benceno y

X denota la fracción molar del disolvente (benceno).

En el caso dado,

(P) = 700 mmHg,

P° = 1atm = 760mmHg

Fracción molar de benceno = 0,9211           (∵ 700/760)

La fracción molar de benceno (X)  = Moles de benceno/Moles de benceno + Moles de hexano

Moles de benceno - Masa molar: 78g / mol -  200 g × (1 mol / 78 g)

= 2.5641 moles de benceno

X = Moles de benceno/Moles de benceno + Moles de hexano

0.9211 = 2.5641 moles Benceno/2.5641 moles Benceno + Moles de Hexano

⇒ 0,9211 × moles de Hexano + 2,3618 = 2,5641    

⇒ 0.9211 × moles de Hexano = 0.2023

∵ Moles de Hexano = 0.2023/0.9211

[tex]= 0.2196 moles[/tex]

[tex]Hexane mass - Molar mass = 86g/mol - 0.2196 mole hexane[/tex] × [tex](86g/mole)[/tex]

[tex]= 18.9g[/tex]

Por tanto, 18,9 g es la respuesta correcta.

Learn more about "Benzene" here:

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Answer:

See explanation

Explanation:

An electrolytic cell functions by a non spontaneous chemical process. Energy is supplied in the form of electricity through a battery to drive the electrochemical process.

A voltaic cell functions by a spontaneous chemical process. Energy or work can be derived from a voltaic cell.

When iron is rusting, a natural voltaic cell is set and the iron is converted to hydrated iron III hydroxide. The set up used for the extraction of sodium metal from brine functions on the basis of electrolysis.

Answer:

The frequency of a wave that has a wavelength of 28 m is 1.07*10⁷ Hz.

Explanation:

Wavelength is the minimum distance between two successive points on the wave that are in the same state of vibration. It is expressed in units of length (m).

Frequency is the number of vibrations that occur in a unit of time. Its unit is s⁻¹ or hertz (Hz).

The propagation speed is the speed with which the wave propagates in the medium, that is, it is the magnitude that measures the speed at which the wave's disturbance propagates along its displacement. Relate the wavelength (λ) and the frequency (f) inversely proportional using the following equation:

v = f * λ.

Being:

Replacing:

2.998*10⁸ m/s= f* 28 m

Solving:

[tex]f=\frac{2.998*10^{8}m/s }{28m}[/tex]

f= 1.07*10⁷ Hz

The frequency of a wave that has a wavelength of 28 m is 1.07*10⁷ Hz.

Answer:

true

Explanation:

As an atom with no charge have same number of proton and electrons

Answer:

1. 0.125 mole

2. 42.5 g

3. 0.61 mole

Explanation:

1. Determination of the number of mole of NaOH.

Mass of NaOH = 5 g

Molar mass of NaOH = 23 + 16 + 1

= 40 g/mol

Mole of NaOH =?

Mole = mass /molar mass

Mole of NaOH = 5/40

Mole NaOH = 0.125 mole

2. Determination of the mass of NH₃.

Mole of NH₃ = 2.5 moles

Molar mass of NH₃ = 14 + (3×1)

= 14 + 3

= 17 g/mol

Mass of NH₃ =?

Mass = mole × molar mass

Mass of NH₃ = 2.5 × 17

Mass of NH₃ = 42.5 g

3. Determination of the number of mole of Ca(NO₃)₂.

Mass of Ca(NO₃)₂ = 100 g

Molar mass of Ca(NO₃)₂ = 40 + 2[14 + (3×16)]

= 40 + 2[14 + 48]

= 40 + 2[62]

= 40 + 124

= 164 g/mol

Mole of Ca(NO₃)₂ =?

Mole = mass /molar mass

Mole of Ca(NO₃)₂ = 100 / 164

Mole of Ca(NO₃)₂ = 0.61 mole