Which one of the following is a balanced equation? a. 2ca (s) + o2 (g) → 2cao (s) b. 6ca (s) + 2o2 (g) → 6cao (s) c. 4ca (s) + o2 (g) → 2cao (s) d. 6ca (s) + 4o2 (g) → 2cao (s)

Option A)

Explanation:

Hi, the balanced equation is the option A)

To be balanced it has to have the same quantity of each element at each side of the equation.

Option B) has more O atoms in the products than  the reactants

Option C) has less Ca atoms in the products than  the reactants

And option D) has less O and Ca atoms in the products than  the reactants

you need to take a look at the periodic system in order to sort these elements into pairs that would most likely exhibit similar chemical properties. first, you need to find elements that are found in the same group (groups are vertical in the periodic system), and then to see whether they have the same valence number. if they meet these criteria, they will have similar properties.

the first pair: ne (neon) and kr (krypton), are noble gases found in group 8

the second pair: li (lithium) and k (potassium), found in group 1

the third pair: s (sulfur) and te (tellurium), found in group 6

water and alcohols have similar properties because water molecules contain hydroxyl groups that can form hydrogen bonds with other water molecules and with alcohol molecules, and likewise alcohol molecules can form hydrogen bonds with other alcohol molecules as well as with water.