Cho muối X vào dd NaOH, đun nóng, thu được một chất khí làm xanh giấy quỳ ẩm. Chất nào sau đây thỏa mãn tính chất của X? A. K2SO4 B. NH4NO3 C. CaCO3
D. FeCl2

Which of the following is an indication that a substance has undergone a chemical change? a. no new product has been formed. b. the color of the substance has not changed. c. the original constitute has not changed. d. the molecular structure has changed.

If 22.5 of nitrogen at 748 mm hg are compressed to 725 mm hg at constant temperature. what is the new volume?

What relationship exists between an enzyme and a catalyst?