If I have an unknown quantity of gas at a pressure of 750 torr, a volume of 25 liters, and a temperature of 300 K, how many moles of gas do I have?

1 mole

Explanation:

Data obtained from the question include:

P (pressure) = 750 torr

But 760torr = 1atm

750 torr = 750/760 = 0.99atm

V (volume) = 25L

T (temperature) = 300K

R (gas constant) = 0.082atm.L/Kmol

n (number of mole) =?

Using the ideal gas equation PV = nRT, we can easily find the number of mole as illustrated below:

PV = nRT

n = PV /RT

n = 0.99 x 25 / 0.082 x 300k

n = 1 mole

Therefore, the number of mole of the gas is 1 mole

the seeing the electronic configuration we can say that the element is fluorine.

fluorine is the most electronegative element in the periodic table.

but by only seeing the configuration we cannot say about its reactivity because we don't know if its configuration after excitation or by addition of electrons.

but if not then, it is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions. as the most electronegative element, it is extremely reactive: almost all other elements, including some noble gases, form compounds with fluorine.