When a magnesium ribbon is burnt in air, what are the two observations that you make?

When magnesium ribbon is burnt in air, the following two observations can be made:

1. Bright White Flame: When magnesium is ignited, it burns with a very bright white flame. This intense luminosity is due to the high temperature and the reaction of magnesium with oxygen in the air to form magnesium oxide.

2. Formation of White Powder: After burning, a white ash or powder is left behind. This powder is magnesium oxide (MgO), which is formed as a result of the reaction between magnesium and oxygen. The reaction can be represented by the chemical equation:

   $2 \text{Mg} + \text{O}_2 \rightarrow 2 \text{MgO}$

These observations indicate that magnesium burns in a vigorous exothermic reaction, producing magnesium oxide as a product.