25 grams of cocoa powder is a small amount that measures 2.82 tbsp (41.7 mL). It is about the size of a golf ball when poured into a loose pile.

In kitchen measures
2.82 tablespoons
8.45 tsp · 2.82 tbsp · 0.176 cups
about the size of a golf ball
Cocoa powder typically ranges 0.5–0.7 g/mL depending on how it's packed. A firmly packed scoop weighs more.