2. when a drop of my pumpkin spice latte accidentally falls into the sploam, the substance begins to glow, then my room is filled with a purple haze. eventually all my furniture is covered in glitter and the original sploam no longer exists. what kind of change (chemical or physical) most likely occurred

Chemical because the first thing disappeared and changed into something completely different. Because you got something new from what you started with, it is chemical.

Idk why its pumpkin spice latte but I'm not going to judge. I prefer drinking bleach.

it can be observed without changing the identity of the object.

it depends on what substance you're talking about as well as many other factors. in quantum mechanics, the observation of particles affects the observers ability to measure certain properties. for example: you can know the velocity of a particle, but you can't know it's position; or you can know it's position, but not it's velocity. it's like trying to find out where a grain of sand is by throwing other grains of sand at it. once you find out where it is, it's been moved. it's also like trying to find an answer to the question of whether or not a tree falling in a forest makes a sound if nobody is there to hear it. paradoxically, the only way to find out is to be there and hear it.