A sample of gas in a cylinder as in the example in Part A has an initial volume of 56.0 L , and you have determined that it contains 1.80 moles of gas. The next day you notice that some of the gas has leaked out. The pressure and temperature remain the same, but the volume has changed to 14.0 L . How many moles of gas (n2) remain in the cylinder

The moles of gas that remain in the cylinder are 0.45

Explanation:

According to the Avogadro's law, the volume of gas is directly proportional to the number of moles of gas at same pressure and temperature. That means,

or

where,

= initial volume of gas = 56.0 L

= final volume of gas = 14.0 L

= initial moles of gas = 1.80  

= final moles of gas = ?

Putting the values , we get:

The moles of gas that remain in the cylinder are 0.45

it means there are 3 atoms of oxygen

hey there!

mass = 6.75 g

volume =   9 cm³

therefore:

d = mass / volume

d   = 6.75 / 9

d = 0.7 g/cm³

answer b