Above 882oC, zirconium has a BCC crystal structure with a = 0.332 nm. Below this temperature, zirconium has an HCP structure with a = 0.2978 nm and c = 0.4735 nm. Determine the percent volume change when BCC zirconium transforms to HCP zirconium. Is that contraction or expansion?

Contraction

Explanation:

From the given information;

Above 88° C

zirconium has a BCC crystal structure with a = 0.332 nm

Below this temperature

zirconium has an HCP structure with a = 0.2978 nm and c = 0.4735 nm

the volume of BCC can now be:

the volume of HCP can now be:

Ths; the volume percent change when BCC zirconium transforms to HCP zirconium can be calculated as:

Hence; it is contraction due to what the negative sign portray, The negative sign signifies that there is contraction during cooling

hope this

explanation:

covalent bonds

consist of pairs of electrons shared by two atoms, and bind the atoms to fixed orientation and requre high energies to break them

ionic bonds

when two atoms differ considerably in their electronegativity, then one of the atoms will lose its electron to the other atom. this results in a positively charged ion(cation) and a negatively charged ion (anion)

thats how its supposed to be