PDF Chapter 2 Matter and Change Answer Key - MRS. MORALES PEP SITE 14.8 g hydrogen + 38.4 g oxygen = x g water; x = 43.2 g water Chapter 2 Review 29. Use Table 2.1 to identify four substances that undergo a physical change if the temperature is decreased from 50 ̊C to -50 ̊C. Describe the nature of the physical change. 2.1 Chlorine, mercury, bromine, and water; Chlorine condenses, and mercury, bromine,