Which of the following is not an indication of a chemical reaction?
two substances burst into flames on contact.
a substance freezes.
bubbles form when two substances are combined.
a solid forms when two substances are combined.

A substance freezes

Explanation:

Two substances bursting into flames on contact can be seen as a combustion reaction, and this usually happens with very volatile substances, and is a chemical reaction that changes the substance on the atomic level.

A substance freezing simply demonstrates a phase change, and does not alter the molecule on any level, apart from the arrangement of the atoms.

Bubbles forming when two substances are combined is the indication that a gas has been formed as a product. The only way a gas can be formed is by a chemical change, usually oxygen or hydrogen is given off.

A solid forming is usually named a precipitation reaction, and the solid is called a precipitate, and this is a chemical reaction that forms an insoluble substance.

question: ray weighs 100 kilograms, his wrestling partner, bobby, weighs 50 kilograms. if ray moves at 4 m s , how fast will bobby have to run at him to apply an equal amount of kinetic energy?

answer: 8 m/s he needs to run twice as fast to keep up so he has some work to do

explanation:   if the mass has units of kilograms and the velocity of meters per second, the kinetic energy has units of kilograms-meters squared per second squared.

question answered by

(jacemorris04)