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4 years ago

How could Mendeleev predict the properties of elements that had not yet been discovered?

Chemistry

1 answer:

icang [17]3 years ago

3 0

It was the element of aluminium where they predict their properties

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A mixture of nitrogen and hydrogen gases, at a total pressure of 663 mm Hg, contains 3.46 grams of nitrogen and 0.156 grams of h

STALIN [3.7K]

Answer: The partial pressure of nitrogen gas is 405.76 mmHg and that of hydrogen gas is 257.24 mmHg

Explanation:

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

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

For nitrogen gas:

Given mass of nitrogen gas = 3.46 g

Molar mass of nitrogen gas = 28 g/mol

Putting values in above equation, we get:

$\text{Moles of nitrogen gas}=\frac{3.46g}{28g/mol}=0.123mol$

For hydrogen gas:

Given mass of hydrogen gas = 0.156 g

Molar mass of hydrogen gas = 2 g/mol

Putting values in above equation, we get:

$\text{Moles of hydrogen gas}=\frac{0.156g}{2g/mol}=0.078mol$

Mole fraction of a gas is calculated by using the formula:

$\chi_{A}=\frac{n_{A}}{n_{A}+n_{B}}$ ......(1)

For nitrogen gas:

Putting values in equation 1, we get:

$\chi_{\text{nitrogen gas}}=\frac{0.123}{0.123+0.078}=0.612$

For hydrogen gas:

Putting values in equation 1, we get:

$\chi_{\text{hydrogen gas}}=\frac{0.078}{0.123+0.078}=0.388$

The partial pressure of a gas is given by Raoult's law, which is:

$p_A=p_T\times \chi_A$ ......(2)

where,

$p_A$ = partial pressure of substance A

$p_T$ = total pressure = 663 mmHg

$\chi_A$ = mole fraction of substance A

For nitrogen gas:

$p_{\text{Nitrogen gas}}=663mmHg\times 0.612\\\\p_{\text{Nitrogen gas}}=405.76mmHg$

For hydrogen gas:

$p_{\text{Hydrogen gas}}=663mmHg\times 0.388\\\\p_{\text{Hydrogen gas}}=257.24mmHg$

Hence, the partial pressure of nitrogen gas is 405.76 mmHg and that of hydrogen gas is 257.24 mmHg

4 0

3 years ago

Explain how Mendel used the F1 generation to conclude that genes are inherited.

fredd [130]

Answer:

studied the generation to see there traits

Explanation:

4 0

3 years ago

Read 2 more answers

Atoms of nonmetallic elements form covalent bonds, but they can also form ionic bonds. how is this possible?

Olin [163]

No ionic bond is between metal and non metal and covalent bond is between two non metals

5 0

4 years ago

Uncrewed vehicles launched into space to collect data are called what?

ozzi

B. Rovers are what you are looking for

6 0

3 years ago

Oxygen gas, generated by the reaction 2 KClO 3 ---- 2 KCl + 3 O 2 , is collected over water at 27 C in a 2.00 L vessel at a tota

laila [671]

Answer:

The moles of KClO3 = 0.052 moles

Explanation:

Step 1: Calculate the pressure of oxygen gas

The oxygen has a total pressure (including water vapour) of 760 mmHg

The pressure of Oxygen = (760 - 26) mmHg

= 734 mmHg of water vapor

Step 2: Calculate the no of moles of oxygen

Using Ideal gas equation

P V = n R T

P = pressure of oxygen in N/m2 ( you should convert 734 mmHg to pascal or N/m2) = 97,858.6 N/m2 or pas

V = 2 litres = 0.002 m3

R = gas constant = 8.31

T= 27oC = 300 K

Applying this equation P V = n R T

97,858.6 x 0.002 = n x 8.31 x 300

n = 0.0785 mol of Oxygen

From the balanced equation

2 KClO 3 ---- 2 KCl + 3 O 2

3 moles of oxygen is produced from 2 moles KClO3

so 0.0785 mole of oxygen will be produced from x

x = (0.0785 x 2 ) / 3

x = 0.052 moles of KClO3

5 0

4 years ago