The reaction 4Al (s) + 3O2 (g) → 2 Al2O3 (s) ΔH° = -3351 kJ
is , and therefore heat is by the reaction.

Polyethylene is a strong synthetic polymer that can be used to make toys and bottles. this makes plastics which are important also to people but sometimes it lead to harmful environmental effects such as global warming if these plastics are burned.

Small amounts of matter are converted intolarge amounts of energy occurs in both fusion and fission reactions. they are nuclear reactions where a change in the identity or characteristics of an atomic nucleus results when it is bombarded with an energetic particle, as in fission, fusion, or radioactive decay.

100cm, because 11.0 cm is 3 figures as they've chosen to include the decimal point. if you have a 3 digit number then anything after the second digit will become 0 if it's to 2 significant figures