Because it is less stable than phosphorous
When the concentration of a reactant is increased, the chemical equilibrium will shift towards the products. More product is formed and the concentration of the reactants decreases as the concentration of the products increases.
1 carbon and 2 oxygen atoms CO2
These are dissolved in water to form colourless solutions, and then mixed together. This mixing leads to a double displacement reaction, essentially resulting in the metals 'swapping' their places in the two compounds, producing lead (II) iodide, and potassium nitrate.
74.62 g of magnesium oxide is formed from 45.00 g magnesium so 74.62-45.00= 29.62 g of oxygen is consumed or in other words a new compound is formed in the burning of magnesium in oxygen with a heavier mass than the pure magnesium.