Mixing the Acid *spoilers maybe?*

[Sursion]

Not really spoilers since it's at the beginning of the game. But anyway. I've just collected all four chemicals and I've got the chemical mixer, but when I try to make the acid it keeps telling me I need a mixing aparatus. Isn't that what the mixer is for? I click and drag the chemicals onto the mixer when it tells me this.

I thought "Oh, well maybe there's something I missed in the laboratory" but the entrance is filled with that stupid red stuff and I can't get in. I've almost died trying. Am I just being an idiot, and there's somewhere else I'm supposed to go? Or am I screwed and have to start over?