All of the following are evidence that a chemical reaction has occurred except . a new substance formed
a new substance formed

a change in temperature occurred
a change in temperature occurred

gas bubbles form
gas bubbles form

matter changes state

the earths atmosphere is made up of nitrogen and oxygen. solids can turn into gasses through a process called sublimation. sublimation is the transition of a substance directly from the solid to the gas phase, without passing through the intermediate liquid phase.

hope this : d

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me

find the sum of the two horizontal vectors and the sum of the two vertical vectors

isoceles right angled triangle