Answer:
2.11 x 10²⁴ molecules.
Explanation:
- <em>It is known that every 1.0 mole of a molecule contains Avogadro's number of molecules (NA = 6.022 x 10²³).</em>
<em><u>Using cross multiplication:</u></em>
1.0 mole of H₂O contains → 6.022 x 10²³ molecules.
3.5 mole of H₂O contains → ??? molecules.
∴ 3.5 mole of H₂O contain = (3.5 mol)(6.022 x 10²³) = 2.11 x 10²⁴ molecules.
Answer : The final number of moles of gas that withdrawn from the tank to lower the pressure of the gas must be, 0.301 mol.
Explanation :
As we know that:

At constant volume and temperature of gas, the pressure will be directly proportional to the number of moles of gas.
The relation between pressure and number of moles of gas will be:

where,
= initial pressure of gas = 24.5 atm
= final pressure of gas = 5.30 atm
= initial number of moles of gas = 1.40 moles
= final number of moles of gas = ?
Now put all the given values in the above expression, we get:


Therefore, the final number of moles of gas that withdrawn from the tank to lower the pressure of the gas must be, 0.301 mol.
The highest electronegativity is in the elements in the top left corner of the periodic table, and the lowest in the bottom right corner. Therefore, traveling up or to the left across the periodic table will increase the electronegativity
C. The number of Valence electrons,
Every atom tries to follow the Octet rule i.e To have 8 electrons in its Valence shell.
Every atom tries to accomodate 8 electrons in its Valence shell to stabilize themselves, Metals usually have 1-3 eletrons in their Valence shell which they donate to non metals so their Valnce shell has 8 electroons, (The previous will now be the Valence shell and it will be full)
Similarly Non metals have 4-7 electrons, they accept electrons from metals so they can have 8 electrons in their Valence shell.
Noble gases already have 8 electrons in their Valance shell, so they do not react and stable.
Hope it helps :)