500 grams is how many liters?

That depends on what the substance is.

If it's 300 grams of air, then it fills several liters of volume.

If it's 300 grams of water, then it fills roughly 0.3 of one liter of volume.

If it's 300 grams of stone or lead, then it's just a thin layer in the bottom of a one-liter jar.