Question

one of relatively few reactions that takes place directly between two solids at room temperature is given in the equation below. in this equation, the 8 h₂o in ba(oh)₂·8 h₂o indicates the presence of eight water molecules. this compound is called barium hydroxide octahydrate. (a) balance the equation. (use the lowest possible coefficients. include states - of - matter under the given conditions in your answer.) ba(oh)₂·8 h₂o(s) + nh₄scn(s) → ba(scn)₂(s) + h₂o(l) + nh₃(g)

Explanation:

Step1: Count atoms on both sides

On the left - hand side, we have 1 Ba, 2 O, 2 H (from Ba(OH)$_2$), 8 H (from 8H$_2$O), 1 N and 1 S (from NH$_4$SCN). On the right - hand side, we have 1 Ba, 2 O, 2 H (from Ba(SCN)$_2$), some H and O from H$_2$O and 1 N and 1 S (from Ba(SCN)$_2$).

Step2: Balance SCN$^-$ group

We have 1 SCN$^-$ in NH$_4$SCN on the left. To balance the SCN$^-$ group on the right in Ba(SCN)$_2$, we need 2 moles of NH$_4$SCN.

Step3: Balance hydrogen and oxygen

After adding 2 moles of NH$_4$SCN, we have more hydrogen and nitrogen. For hydrogen and oxygen balance, the balanced equation is: Ba(OH)$_2\cdot$8H$_2$O(s)+2NH$_4$SCN(s)$
ightarrow$Ba(SCN)$_2$(s)+10H$_2$O(l)+2NH$_3$(g)

Answer:

Ba(OH)$_2\cdot$8H$_2$O(s)+2NH$_4$SCN(s)$
ightarrow$Ba(SCN)$_2$(s)+10H$_2$O(l)+2NH$_3$(g)