It is two or more objects and different things that can be removed from each other.
1 mole of any gas under STP has volume 22.4 L
So 2.50 moles of any gas ( including oxygen)
2.50 mol *(22.4L/1 mol)=56.0 L
Explanation:
Standard formation of an substance is defined as formation of one mole of substance from its constituting elements.
Chromium(III) nitrate is composed of chromium, nitrogen and three oxygen atoms.
A balanced chemical equation for the standard formation reaction of solid chromium(III) nitrate