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1 year ago

A sample of carbon dioxide gas (CO2) contains 8.551 x 10^25 molecules. How many moles of carbon dioxide does this represent

2 answers:

0 0

Answer:

142.0mol CO2

Explanation:

To convert from molecules to moles we must divide the amount of molecules by Avagadro’s number, 6.02 x 10^23.

8.551 x 10^25 / 6.02 x 10^23 = 142.0mol CO2

vladimir1956 [14]1 year ago

0 0

Answer:

Explanation:

moles= no. of molecules/ avagardo number

=8.511*10^25/ 6.022*10^23

=14.13 moles

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A pure gold bar is made of 19.55 mol of gold. What is the mass of the bar in grams

Law Incorporation [45]

<span>(19.55 mol Au) / ( 1 ) x (196.97 g Au) / ( 1 mol Au) =
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3850.76 g Au

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1 year ago

Read 2 more answers

Question 2: Phase Changes (14 points) a. Rewrite each of the following equations for phase changes, to include the heat required

lilavasa [31]

Explanation:

(i) The equilibrium reaction equation will be as follows.

$H_{2}O(l) \rightleftharpoons H_{2}O(s)$

A reaction in which there will be absorption of heat energy is known as endothermic reaction.

A reaction in which there will be release of heat energy is known as exothermic reaction.

As liquid state of water is changing into solid state. So, it means that molecules of water came close to each other. Hence, there will be release of heat this means that reaction is exothermic in nature.

Hence, phase change from liquid to solid will be exothermic in nature.

Latent heat of fusion is defined as the amount of energy necessary to convert 1 gram of a solid into liquid state at its melting point.

So, when solid state of water changes into liquid state then it means energy is absorbed by the molecules of ice due to which they have gained kinetic energy. Hence, they moved away from each other leading to formation of liquid state of water.

Latent heat of freezing of liquid water is 334 J/g.

Specific heat of liquid water is 4.186 $J/g ^{o}C$

Specific heat of steam is 1.996 $kJ/kg/^{o}K$

Specific heat of ice is 2.1 $kJ/kg/^{o}K$

(ii) The equilibrium reaction equation will be as follows.

$H_{2}O(l) \rightleftharpoons H_{2}O(g)$

As liquid state of water is changing into gaseous or vapor state. So, it means molecules of liquid water has gained kinetic energy hence, they colloid more rapidly with each other.

As a result, heat will be absorbed by the liquid state of water. Hence, heat will be absorbed. Therefore, phase change from liquid to gas will be endothermic in nature.

Whereas when gaseous state of water will change into liquid state then heat will be released during this process of condensation. As a result, in that case reaction will be exothermic in nature.

5 0

2 years ago

In 200 g of a concentrated solution of 70.4 wt% nitric acid (r = 1.41 g/mL, FW(HNO3) = 63.01 g/mol), how many grams of water are

mars1129 [50]

Answer:

59.2 grams

Explanation:

We are given that 70.4% of the weight of the total 200 g of the concentration is made up of nitric acid, the remaining information is not required to solve the problem. Since water and nitric acid are the only components of the solution, the total weight of water is given by:

$W = 200*(1-0.704)\\W=59.2\ g$

There are 59.2 grams of water in this solution.

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2 years ago

Analyze and solve this partially completed galvanic cell puzzle. There are 4 electrodes each identified by a letter of the alpha

klasskru [66]

Complete Question

The complete question is shown on the first uploaded image

Answer:

The correct option is $E_{cell}__{AC}} = 0.94$

Explanation:

From the question we are told that

the cell voltage for AD is $E_{cell}__{AD}} = 1.56V$

From the data give we can see that

$E_{cell}__{AD}} - E_{cell}__{BD}} = E_{cell}__{AB}}$

i.e $1.56 - 1.53 = 0.03$

In the same way we can say that

$E_{cell}__{AD}}-E_{cell}__{CD}} = E_{cell}__{AC}}$

=> $E_{cell}__{AC}}=1.56- 0.62$

$E_{cell}__{AC}} = 0.94$

5 0

1 year ago

According to the Bohr model, the energy of the hydrogen atom is given by the equation: E = (-21.7 x 10 -19 J)/ n 2 Calculate the

Anit [1.1K]

Answer:

91.6 nm

Explanation:

The energy of the hydrogen atom can be calculated by the emission of a photon. When an electron is excited it goes from to the next energetic level, and when it returns to its ground state, it emits a photon. Hydrogen has only one electron, which is at the level n = 1. So, the equation is given:

E = (-21.7x10⁻¹⁹J)/1²

E = -21.7x10⁻¹⁹J

The energy of the photon is the energy absorbed, and because of that is positive (the opposite of the energy released by the electron). This energy can be calculated by:

E = h*c/λ

Where h is the Planck's constant (6.626x10⁻³⁴ J.s), c is the speed of the light (3.00x10⁸ m/s), and λ is the wavelength of the photon.

21.7x10⁻¹⁹ = 6.626x10⁻³⁴ * 3.00x10⁸/λ

λ = 9.16x10⁻⁸ m

λ = 91.6 nm

7 0

1 year ago