Answer:
There are 5 significant digits in 0.23100.
Explanation:
This is because all non-zero digits are considered significant and zeros after decimal points are considered significant.
Answer: Combustion changes the potential chemical energy into kinetic energy in the form of heat. For combustion an organic wood combines with oxygen already in the air and undergoes a chemical reaction that gives off carbon dioxide,water,and energy in the form of heat and light.
Answer:
the newspaper one is a chemical change because the chemicals in the paper have reacted with something and turned a different color. the wax one is a physical change because it is a change in the phase of matter, which is always a physical change (still the same substance chemically)
Answer: When coal is burned, chemical potential energy is transformed into thermal energy, light energy, and sound energy. Only the thermal energy is used for electricity production. Light and sound energy dissipate into the environment, immediately reducing efficiency.
Hope this helps.
