Final answer:
In the experiment, the temperature increase and the emergence of a sulfur smell both indicate that a chemical reaction took place, forming a new substance.
- The solution gave off a smell of sulfur.
- Solution temperature changed from 10oC to 20oC.
Step-by-step explanation:
The observations that indicate a new substance was formed during the experiment are the temperature change from 10°C to 20°C and the detection of a sulfur smell.
These are both classic signs of a chemical reaction. An increase in temperature without applying heat externally suggests an exothermic reaction, where the reactants release energy as they form new products. The emission of a sulfur smell suggests that the new substance has different properties (olfactory properties, in this case) from the reactants, which is a strong indication that a chemical change has occurred.