Above 882°c, titanium has a bcc crystal structure, with a = 0.332 nm. below this temperature, titanium has a hcp structure, with a = 0.2978 nm and c = 0.4735 nm. determine the percent volume change when bcc titanium transforms to hcp titanium. is this a contraction or expansion?

a = for BCC crystal structure  (given)

a = and c = for HCP crystal structure (given)

Volume of BCC =

Substituting the value:

Volume of BCC = =

Volume of HCP =

Substituting the values:

Volume of HCP =

Percentage change is calculated as:

Percentage change = %

Substituting the values:

Percentage change = %

Percentage change = %

The negative sign in percentage change indicates that there is a contraction during cooling.

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.