The decomposition of gaseous \(\text{X}\) proceeds according to the balanced equation below:
\[ 2\,\text{X}(g) \rightarrow \text{Y}(g) + \text{Z}(g) \]
A sample of pure \(\text{X}(g)\) is placed into a rigid \(1.0\text{ L}\) vessel at a constant temperature. The particulate diagrams below represent the contents of the vessel at three successive times: \(t = 0\text{ s}\), \(t = 100\text{ s}\), and \(t = 200\text{ s}\). Each particle represents \(1.0 \times 10^{-3}\text{ mol}\) of the indicated substance.

Based on the representations, what is the order of the reaction with respect to \(\text{X}\), and what is the value of the rate constant \(k\)?