What were some of the key motivations behind European imperialism in the late nineteenth century?

I think that one of the big ones might be that Europe had lost a lot of its colonies in the Americas due to the Age of Revolutions- during which the American Rev, Haitian Rev and other revolutions in Latin America took place

-They needed more colonies to replace the ones they lost

Also, the Industrial Revolution in Britain, and subsequent Industrial Revs started around this time in Europe, so they needed the raw materials that colonies in Africa+ others could provide (guano (I think this was from Peru and Colombia), precious metals (De Beers Diamonds in S Africa), and rubber (Congo) are some that they provided).
These colonies also provided markets for European manufactured goods (countries in Africa still depend on Europe for most of their trade today)

-Needed raw materials for industrial rev (plus colonies provided markets for manufactured goods made during rev- cycle)

Asia (spheres of influence) also provided markets for manufactured goods

I took world last year, so if anything seems wrong feel free to let me know!

Provide more information so i can answer your question; )