Four separate procedures each involve adding 1.00 g of a substance to 50.0 mL of…
CHEMISTRY · Single correct · AP · Chemistry · Chemical Reactions · Chemical Reactions
Problem
Four separate procedures each involve adding 1.00 g of a substance to 50.0 mL of water initially at 20.0 °C. The maximum temperature reached in each case is recorded.
• Procedure P: 1.00 g KNO₃ → 17.1 °C
• Procedure Q: 1.00 g NaCl → 20.0 °C
• Procedure R: 1.00 g CaO → 32.5 °C (slight sizzling observed)
• Procedure S: 1.00 g sucrose → 20.3 °C
Which procedure provides the most convincing evidence that a chemical, rather than physical, change has occurred?
(a) Procedure S
(b) Procedure R
(c) Procedure P
(d) None of the procedures provide convincing evidence