Question
What is the correct balanced symbol equation for the reaction of calcium with oxygen? [ 2 mathrm(Ca)+mathrm(O)_(2) arrow 2 mathrm(CaO) mathrm(Ca)+mathrm(O)_(2) arrow 2 mathrm(CaO) 2 mathrm(Ca)+2 mathrm(O)_(2) arrow 2 mathrm(CaO)_(2) ]
Answer
4.5
(245 Votes)
Harriet
Master · Tutor for 5 years
Answer
A) 2Ca + O2 → 2CaO
Explanation
Chemical equations must be balanced so that they adhere to the law of conservation of mass. This law stipulates that matter cannot be created or destroyed, and, hence, the amount of each element does not change in a chemical reaction. It, therefore, follows that the same number of each type of atom needs to appear on both sides of the chemical equation.In this question, calcium (Ca) chemically reacts with oxygen (O2) to create calcium oxide (CaO). The act of balancing the equation involves equating the number of each atom on either side of the reaction – imbalance the number on either side would violate the aforementioned law of conservation.By analyzing the answer choices,A) 2Ca + O2 → 2CaO Without balancing, one atom of Ca requires half a molecule of O2 to form a molecule of CaO. But in reactions, O2 molecules never split up like that. Each molecule of O2 must be used in full during reactions and so, the equation must consider this: giving 2Ca + O2 yields 2CaO.