Download Chemical reactions occur when substances go through chemical

Notes 7.1
Chemical reactions occur when substances go through chemical changes to form
new substances.
You can often see chemical reactions happening when they form new substances.
Chemical reactions rearrange atoms. When gasoline burns the combination of
Isooctane and oxygen react to form Carbon dioxide, Water and energy! (see
figure 3 pg 221)
Chemical reactions always involve changes in energy. Energy must be added to
break bonds.
Energy can be transferred as heat, electricity, sound or light.
Forming bonds releases energy.
Energy is conserved in chemical reactions. Energy is never created or destroyed.
Reactions that release energy are exothermic.
Reactions that absorb energy are endothermic.
Photosynthesis is an endothermic reaction. During photosynthesis plants use
energy from light to form high energy bonds that make sugar that the plants use
for energy.
A product of photosynthesis is oxygen that the plants release into the air.