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3 years ago

How many moles are in 4.25*10^25 atoms of helium?

Chemistry

1 answer:

Murljashka [212]3 years ago

5 0

Answer:

<h2>70.60 moles</h2>

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

$n = \frac{N}{L} \\$

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question we have

$n = \frac{4.25 \times {10}^{25} }{6.02 \times {10}^{23} } \\ = 70.598006...$

We have the final answer as

<h3>70.60 moles</h3>

Hope this helps you

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After adding 20.0 mL of 5% NaOH solution into the remaining organic layer, followed by mixing and venting, the solution separate

Arisa [49]

Answer:

Explanation:

The objective of this experiment is to match the expected result with each of the propositions given after the experiment had been carried out.

1. The top layer was the organic  layer. This is because all the organic compounds have lesser density than water except chloroform that will be formed when NaOH is added.

2. 9-fluorenone was most soluble in the organic layer. This is so as a result of its non-polar carbon structure.

3. Deprotonated chloroanilic acid was most soluble in the aqueous layer as a result of the formation of an electrovalent bond with water.

4. The bottom layer was the aqueous layer as a result of the huge amount of water density.

5. The organic layer was a yellow colored solution.

6. The aqueous layer turned into a pink colored solution.

7 0

3 years ago

The product gas is then passed through a concentrated solution of KOH to remove the CO2. After passage through the KOH solution,

Kamila [148]

Answer: The mass percent of nitrogen gas in the compound is 13.3 %

Explanation:

Assuming the chemical equation of the compound forming product gases is:

$\text{Compound}\xrightarrow[CuO(s)]{Hot}N_2(g)+CO_2(g)+H_2O(g)$

Now, the product gases are treated with KOH to remove carbon dioxide.

We are given:

$p_{Total}=726torr\\P_{water}=23.8torr\\$

So, pressure of nitrogen gas will be = $p_{Total}-p_{water}=726-23.8=702.2torr$

To calculate the number of moles of nitrogen, we use the equation given by ideal gas which follows:

$PV=nRT$

where,

P = pressure of nitrogen gas = 702.2 torr = 0.924 atm (Conversion factor: 1 atm = 760 torr)

V = Volume of nitrogen gas = 31.8 mL = 0.0318 L (Conversion factor: 1 L = 1000 mL)

T = Temperature of nitrogen gas = $25^oC=[25+273]K=298K$

R = Gas constant = $0.0821\text{ L. atm }mol^{-1}K^{-1}$

n = number of moles of nitrogen gas = ?

Putting values in above equation, we get:

$0.924atm\times 0.0318L=n\times 0.0821\text{ L atm }mol^{-1}K^{-1}\times 298K\\n_{mix}=\frac{0.924\times 0.0318}{0.0821\times 298}=0.0012mol$

To calculate the mass of nitrogen gas, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Molar mass of nitrogen gas = 28 g/mol

Moles of nitrogen gas = 0.0012 moles

Putting values in above equation, we get:

$0.0012mol=\frac{\text{Mass of nitrogen gas}}{28g/mol}\\\\\text{Mass of nitrogen gas}=(0.0012mol\times 28g/mol)=0.0336g$

To calculate the mass percent of nitrogen gas in compound, we use the equation:

$\text{Mass percent of nitrogen gas}=\frac{\text{Mass of nitrogen gas}}{\text{Mass of compound}}\times 100$

Mass of compound = 0.253 g

Mass of nitrogen gas = 0.0336 g

Putting values in above equation, we get:

$\text{Mass percent of nitrogen gas}=\frac{0.0336g}{0.253g}\times 100=13.3\%$

Hence, the mass percent of nitrogen gas in the compound is 13.3 %

8 0

4 years ago

Determine the amount of energy (heat) in joules required to raise the temperature of 5 kg of iron from 50°C to 200°C.

larisa [96]

333,000 Joules is the amount of energy (heat) in joules required to raise the temperature of 5 kg of iron from 50°C to 200°C.

Explanation:

Data given:

mass of iron 5 Kg or 5000

initial temperature = 50 degree centigrade

final temperature = 200 degrees centigrade

change in temperature (Δ T= 200 -50 degrees centigrade)

= 150 °C

cp (specific heat capacity of iron) = 0.444j/gram C

q (heat supplied) = ?

applying the formula,

q=mcΔT

putting the values in the equation:

q = 5000 X 0.444 X150

q = 333,000 Joules of energy.

The heat required 333,000 Joules of energy is required.

4 0

4 years ago

Vitellium (Vi) has the following composition:Vi-188: 187.9122 amu; 10.861%Vi-191: 190.9047 amu; 12.428%Vi-193: 192.8938 amu; 76.

yKpoI14uk [10]

10.861% / 100 = 0.10861

12.428 % / 100 = 0.12428

(0.10861 * 187.9122) + (0.12428 * 190.9407) + (0.76711 x 192.8938)

= 192.1100 amu .

hope this helps!

7 0

3 years ago

Which class of molecules functions as chemical signals? hormones water carbohydrates proteins

leonid [27]

Answer:

hormones - the first choice

3 0

4 years ago

Read 2 more answers