Answer: There are 7.4 moles of helium gas present in a 1.85 liter container at the same temperature and pressure.
Explanation:
Given:
= 2.25 L,
= 9.0 mol
= 1.85 L,
= ?
Formula used to calculate the moles of helium are as follows.

Substitute the values into above formula as follows.

Thus, we can conclude that there are 7.4 moles of helium gas present in a 1.85 liter container at the same temperature and pressure.
4. NaOH
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Atomic mass is the answer!!
Explanation: An elements atomic number won’t be able to change
The first basic metals on the periodic table are alkali metals.