Question

1). Convert 30.1 L of argon gas at STP into atoms.:

2). How many moles of barium nitrate contain 6.80 x 1024 particles?

Answer 1

Because we are told to consider the Argon gas at STP (standard temperature and pressure),

we are able to assume that Ar behaves like an ideal gas.

Therefore, we know

volume of 1 mole of gas at STP conditions is 22.4 L (for an ideal gas)

DETERMINE HOW MANY MOLES OF GAS IN 75 L

75 L x 1 mol ~= 3.348 mol Ar (g)

22.4 L

CONVERT MOLES TO ATOMS USING AVAGADRO'S NUMBER

3.348 mol Ar x 6.02x1023 atoms Ar =

1 mol Ar

ANSWER:

= 2.0x1024 atoms Ar