decribe three signs that a chemical reaction has taken place and ex. of each sign?

Answer 1

Change in temperature - heat released when wood is burned

Change in color - red to blue litmus paper

Bubbles produced - zinc added to acid causes bubbles of hydrogen gas

Answer 2

A precipitate forms, Heat is evolved, formation of a gas.

If a precipitate forms obviously something new is made that isnt soluable anymore, such as one made from barium chloride into barium sulphate precipitate.

An example of heat being evolved is the addition of water to any concentrated acid as an exothermic reaction.

An the formation of a gas is a new product formed threw chemical reaction such as the formation of HBr gas threw the reaction of Butanol and Sodium Bromide

Answer 3

Clues that a chemical reaction has occured are:
The colour changes
A solid Forms
Bubbles Form
Heat and or a Flame is produced/or head is absorbed

The driving forces of a chemical reaction are:
A formation of a solid (precipitate)
Formation of Water
Transfer of Electrons
Formation of a Gas

Answer 4

Yugtygyugh

Answer 5

Change in temperature - heat released when wood is burned

Change in color - red to blue litmus paper

Bubbles produced - zinc added to acid causes bubbles of hydrogen gas