the acid then the more acid particles per 100cm3 so more collisions per second and then there will be more successful collisions per second.
If the starting temperature of the acid is different each time the speed at which the acid particles collide with the magnesium ribbon will increase more the higher the temperature goes. This means the acid particles move with more energy, which means they will collide with the magnesium with more energy, which will give more successful collisions per second.
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