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

Total solidification times of three casting geometries are to be compared: a sphere, a cylinder, in which the length-to-diameter ration - 1.0, and a cube. volume = 1000 cm^3 for all three shhapes, and the same casting alloy is used. a) determine the solidification times of each geometry b) based on the results of part (a), which geometric element would make the best riser? c) if the mold constant = 3.5 min/cm^2 in chvorinov's rule, compute the total solidification time for each casting.

The diagram shows a series of volcanic island and a hot spot determine the direction of movement of the tectonic plate that for the island

If two students are running down the hall toward each other, trying to get to class, and they have the same mass and acceleration, what will happen when they collide? will their forces cancel out or will each one experience a reaction?