. A student is conducting an investigation to determine the identity of an unknown substance. The following data were collected: 1. The substance is yellow 2. The substance melts at 273 degrees Celsius 3. When placed in water the substance floats. 4. When in the presecne of a flame, the substance does not burn. 5. When the substance is addred to hydrochloric acid, a gas forms and a temperature change occurs. Which of these observations represents physical properties of the substance? A. 1, 2, 3 B. 1, 3, 5 C. 1, 2, 4 D. 3, 4, 5