Hii please help me (show work pls) What is the volume of 2.5 moles of O2 at STP?

How many moles of gas is 78.4 L?

What is the molar mass of a gas that has a density of 1.43 g/L?

the catch is that the top numbers are atomic masses the bottom numbers are the numbers of protons and electrons in an uncharged atom. they are the number of that atoms as you would find them on the periodic table. further, the numbers on the left are used to determine the missing numbers on the right

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer

257 grams h2o i think

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