After looking at the schematics of the bubble, he finds that it holds 0.750 moles of gas at Standard Temperature and Pressure. Unfortunately for Rooster, helium gas is not sold by the mole, only by the liter. He needs to know how many liters of gas 0.750 moles of helium is.

16.8 L

Explanation:

From the question given above, the following data were obtained:

Number of mole of He = 0.750 mole

Volume of He =?

Recall:

1 mole of any gas occupy 22.4 L at STP. This also implies that 1 mole of He occupies 22.4 L at STP.

Finally, we shall determine the volume occupied by 0.750 mole of He. This can be obtained as follow:

1 mole of He occupied 22.4 L at STP.

Therefore, 0.750 mole of He will occupy = 0.750 × 22.4 = 16.8 L at STP.

Thus, 0.750 mole of He is equivalent to 16.8 L

space exploration has led to the development and technological improvement of many everyday items. (if this answer is wrong i will find the right answer) : )