4. Explain what properties of atom and molecules allow them to be identified by how they absorb or emit light. What determines the light emitted or absorbed? Name the experimental technique for identifying a sample of an unknown gas.

shows up as a (purple)/ (flashing) red or blue dot getting bigger and brighter.

explanation:

see the picture for the vector

the magnitude of the vector by pythagorean theorem

r = √( (-10)^2 + (3)^2 ) = √109

magnitude = √109 units

the direction angle between vector and x-axis is

tan^(-1)(3/10) = 16.699

so the direction is approximately 16.7 degrees north of west