Crystals are characterized by particular patterns that repeat in how many dimensions? a. three dimensions b. one dimension only c. two dimensions only

A. three dimensions

Explanation:

Crystal lattice have a three dimensional array of repeating units. For example, in the NaCl crystal the repeating units are the Na⁺ and Cl⁻ ions. The Na⁺ and Cl⁻ ions are arranged alternately along the x, y and z axis. The smallest repeating unit of a cell is called unit cell. Crystal lattice have a definite geometry which is because of this rigid array of unit cells.

the reaction mixture contains some ammonia, plus a lot of unreacted nitrogen and hydrogen. the mixture is cooled and compressed, causing the ammonia gas to condense into a liquid. the liquefied ammonia is separated and removed. the unreacted nitrogen and hydrogen are then recycled back into the reactor .