Question

part 2- write a balanced molecular equation for the following reactions.

1. solid calcium metal reacts with liquid water to produce gaseous hydrogen and aqueous calcium hydroxide.

Explanation:

Step1: Write the unbalanced equation

Calcium (\(Ca\)) reacts with water (\(H_2O\)) to form hydrogen (\(H_2\)) and calcium hydroxide (\(Ca(OH)_2\)). The unbalanced equation is \(Ca + H_2O
ightarrow H_2+Ca(OH)_2\).

Step2: Balance the hydrogen atoms

On the right - hand side, there are \(4\) hydrogen atoms in \(Ca(OH)_2\) and \(2\) in \(H_2\) (total \(6\) hydrogen atoms). On the left - hand side, there are \(2\) hydrogen atoms in \(H_2O\). So, we put a coefficient of \(2\) in front of \(H_2O\). The equation becomes \(Ca + 2H_2O
ightarrow H_2+Ca(OH)_2\). Now, the hydrogen atoms are balanced (\(4\) on each side).

Step3: Check the balance of other atoms

Calcium atoms: \(1\) on the left and \(1\) on the right. Oxygen atoms: \(2\) on the left (\(2\times1\) from \(2H_2O\)) and \(2\) on the right (\(2\) from \(Ca(OH)_2\)).

Answer:

\(Ca + 2H_2O = H_2+Ca(OH)_2\)