1) Write the complete and balanced equation for reaction of Calcium metal and a block of solid (P) \( \mathrm{Pa}_{4}^{+2} \mathrm{P}_{4}^{-3} \)

Calcium (Ca) typically reacts with phosphorus (P) in its elemental form. However, the specific species you've mentioned - \( \mathrm{Pa}_{4}^{+2} \mathrm{P}_{4}^{-3} \) - isn't conventional in chemical literature. Assuming you're referencing calcium reacting with black phosphorus (which could be represented as P), the balanced equation for the reaction would look like this: \[ 3 \, \text{Ca} + 2 \, \text{P} \rightarrow \text{Ca}_3\text{P}_2 \] This reaction forms calcium phosphide, a compound that can be used in various applications, including as a semiconductor and in luminescent materials. In more general terms, calcium can react with other phosphorus allotropes, and the products may vary. Always remember to adjust stoichiometry as needed based on the allotropes or compounds involved!