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IrinaK [193]
3 years ago
12

Since the number of atoms in a substance is so large , a unit to count them was created. This unit is the number of atoms in 12

grams of carbon-12 known as
Chemistry
1 answer:
larisa86 [58]3 years ago
7 0

The number of atoms in one mole of any substance is measured by Avogadro's number. The value of Avogadro's number is 6.023 x 10 ^23. It is named after scientist Avogadro who proposed this number. 12 grams of carbon-12 represents 1 mole of carbon-12. For this reason, the number of atoms present in 1 mole of any substance is 6.023 x 10 ^23. Therefore, the number of atoms present in 1 mole carbon-12 is 6.023 x 10^23.


(Answer) This unit is the number of atoms in 12 grams of carbon-12 and known as Avogadro's number.

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A 15.0-L scuba diving tank contains a helium-oxygen (heliox) mixture made up of 23.0 g of He and 4.14 g of O2 at 298 K. Calculat
EleoNora [17]

<u>Answer:</u> The mole fraction of Helium is 0.978 and that of oxygen gas is 0.022

<u>Explanation:</u>

To calculate the number of moles, we use the equation:

\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}      .....(1)

  • <u>For helium:</u>

Given mass of helium = 23 g

Molar mass of helium = 4 g/mol

Putting values in equation 1, we get:

\text{Moles of helium}=\frac{23g}{4g/mol}=5.75mol

  • <u>For oxygen gas:</u>

Given mass of oxygen gas = 4.14 g

Molar mass of oxygen gas = 32 g/mol

Putting values in equation 1, we get:

\text{Moles of oxygen gas}=\frac{4.14g}{32g/mol}=0.129mol

Mole fraction of a substance is given by:

\chi_A=\frac{n_A}{n_A+n_B}

  • <u>For helium:</u>

Moles of helium = 5.75 moles

Total moles = [5.75 + 0.129] = 5.879 moles

Putting values in above equation, we get:

\chi_{(He)}=\frac{5.75}{5.879}=0.978

  • <u>For oxygen gas:</u>

Moles of oxygen gas = 0.129 moles

Total moles = [5.75 + 0.129] = 5.879 moles

Putting values in above equation, we get:

\chi_{(O_2)}=\frac{0.129}{5.879}=0.022

Hence, the mole fraction of Helium is 0.978 and that of oxygen gas is 0.022

3 0
4 years ago
Indicar que elemento es de transición *
Musya8 [376]

Answer:

c hierro

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6 0
3 years ago
K for enolization of 2,4-cyclohexadienone is about 1013. Explain why the enol is so much more stable than the keto tautomer.
torisob [31]

Answer:

Because the value of K is huge.

Explanation:

The tautomer is a kind of isomer in which exist an equilibrium between a ketone and an enol, or between an aldehyde and an enol. So, in the enolization, the ketone is the reactant and the enol is the product.

The equilibrium reaction can be characterized by an equilibrium constant, which is the ratio of the concentration of the products by the concentration of the reactants.

Because the constant K is extremely large (10¹³) we can conclude that the concentration of the product will be greater than the concentration of the reactant, in the equilibrium. It means that the concentration of the enol will be greater.

So, the ketone is unstable and forms in a great amount the more stable product, the enol.

4 0
3 years ago
Use the ideal-gas law to estimate the number of air molecules in your physics lab room, assuming all the air is N2. Assume a roo
stiv31 [10]

Answer:

4.13×10²⁷ molecules of N₂ are in the room

Explanation:

ideal gases Law → P . V = n . R . T

Pressure . volume = moles . Ideal Gases Constant . T° K

T°K = T°C + 273 → 20°C + 273 = 293K

Let's determine the volume of the room:

18 ft . 18 ft . 18ft = 5832 ft³

We convert the ft³ to L → 5832 ft³ . 28.3L / 1 ft³ = 165045.6 L

1 atm .  165045.6 L = n . 0.082 L.atm/mol.K . 293K

(1 atm .  165045.6 L) / 0.082 L.atm/mol.K . 293K = n

6869.4 moles of N₂ are in the room

If we want to find out the number of molecules we multiply the moles by NA

6869.4 mol . 6.02×10²³ = 4.13×10²⁷ molecules

4 0
3 years ago
Create: Click Reset. Use the Gizmo to create a path in which the carbon atom goes from the atmosphere to the hydrosphere, biosph
Solnce55 [7]

Answer:

From the atmosphere to the hydrosphere by diffusion.

From the atmosphere to the biosphere by photosynthesis.

From the atmosphere to the geosphere by rainfall.

Explanation:

Carbon atom goes from the atmosphere to the hydrosphere by the process of diffusion because there is high concentration of carbondioxide present in the atmosphere. The carbon atom goes from the atmosphere to the biosphere by the process of photosynthesis in plants which uses carbondioxide gas as a raw material in the process for the preparation of organic compounds such as glucose. The carbon atom goes from the atmosphere to the geosphere with the help of rain. When carbondioxide gas react with water in the atmosphere, carbonic acid is formed and comes to the ground through rainfall.

7 0
3 years ago
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