Read the following case and answer the questions given below:
During a power cut, Riya lit a candle to study. As the candle burned, she observed that the solid wax near the flame melted into liquid wax, while some of the melted wax flowed down the sides of the candle and later solidified on cooling. She also noticed that the flame produced light and heat, and smoke and gases were released during burning. Her teacher explained that the burning of a candle is an interesting example because more than one type of change takes place at the same time. Riya wondered how these different observations could be classified based on the changes occurring in the candle.
1. After extinguishing the candle, Riya noticed that the melted wax became solid again.
Which conclusion can she draw from this observation?
2. Riya wanted to identify which observation from the case provides evidence that a chemical change has occurred.
Which observation should she choose?
3.
Riya wanted to identify the strongest evidence from the case that shows a chemical change had taken place.
Which observation best supports her conclusion?
4. Riya arranged the events she observed during the burning of the candle in the following sequence.
Which sequence is scientifically correct?