When a candle burns, the products of combustion are carbon dioxide and water. Chemical expression: C25H52+O2→ (ignite) CO2+H2O. The combustion phenomenon in oxygen cylinder is that the flame is bright and emits white light, releasing heat, and water mist appears on the bottle wall. Light the candle, cover it with a cold and dry beaker for 5 minutes, and then turn the beaker quickly. It was found that the inner wall of the beaker became blurred and water droplets were produced, indicating that the candle burned to produce water.
Extended data
When the candle is lit, the initial flame is very small and gradually becomes larger. The flame is divided into three layers (outer flame, inner flame and flame core). The center of the flame is mainly candle vapor with the lowest temperature. The paraffin in the internal flame is not fully burned, and the temperature is higher than the flame center. Because there are some carbon particles, the outer flame is in full contact with air, the flame is the brightest, the combustion is full and the temperature is the highest.
It was recorded in the Song Dynasty that there was a candle trade in the border trade with Xixia at that time. Candle, as a kind of foreign trade and foreign exchange, shows that although it was widely used at that time, it was still precious. 1820, a Frenchman, Jean Bessie, invented a wick made of three cotton threads, which made the wick loosen naturally when burning, and the end just tilted to the outside of the flame, so it could burn completely.
Generally, the surface of coarse wax often has a taste, and there is a layer of frost on it. Different crude waxes will bring different smells. The same candle also comes in many sizes. For example, the extruded cylindrical wax has four sizes: 8×25 cm, 8×20 cm, 7× 15 cm and 7× 10 cm.
References:
Baidu Encyclopedia _ Candles (paraffin lighting items)