Spores in the air or contamination through some sort of insect interaction. In an open system, there are billions of microbial agents floating around. With an open container containing a food source and time, the likelihood of contamination is nearly %100.
Answer:
In calcium oxide (CaO), oxygen and calcium are respectively a non-metal and a metal, whose bonding is based on the exchange of electrons to form an ionic bond, which balances their charges and makes it chemically stable.
Explanation:
<em>What is the reason that in the calcium oxide molecule is caO and not Ca₂O or CaO₂?</em>
Calcium is a metallic element -a soft metal- that is capable of bonding with a non-metallic element such as oxygen to form an ionic bond, so that each Ca atom will bond to a single O atom.
CaO (calcium oxide)
- <em>Ca Z = 20 </em>
- <em>O Z = 8</em>
Ca + O ---→ Ca⁺² + O ⁻²
K L M N K L K L M K L
2 8 8 2 2 6 2 8 8 2 8
The electron exchange that is observed occurs between +atom and atom, and for this reason the chemical formula of calcium oxide is CaO.
Calcium oxide (lime) is obtained by heating calcium carbonate (CaCO₃) to very high temperatures through the following reaction
CaCO₃ + heat → CaO + CO₂
