A phosphorus molecule consists of only four phosphorus atoms. What formula represents a phosphorus molecule?
Write a chemical equation showing phosphorus reacting with chlorine to make phosphorus(III) chloride, PCl₃.
Complete the dot-and-cross diagram to show the electron arrangement in a molecule of phosphorus(III) chloride, PCl₃. Include only outer-shell electrons.
Use the bond energies listed in the table to work out the energy change, in kJ/mol, for the reaction.
Decide whether the energy change for this reaction is exothermic or endothermic. Give a reason.
The reaction reaches equilibrium under certain conditions. State and explain the effect, if any, on the position of equilibrium if the pressure is increased. Keep all other conditions the same.
Phosphine, PH₃, is made by reacting water with calcium phosphide, Ca₃P₂. Balance the chemical equation for this reaction.
State the formula for the ammonium ion.
Suggest the formula for phosphonium iodide.
Calcium phosphate contains the phosphate ion, PO₄^{3}⁻. What is the formula of calcium phosphate?
Calculate the empirical formula of the compound.
The compound has a relative molecular mass of 66. Deduce the molecular formula of the compound.