Examlex
The atomic mass of N is 14 u and that of Ca is 40 u. The proportion of N by mass in the compound Ca3N2 is
Q1: A 60-kg woman climbs a mountain 2000
Q4: Information about the origin of the universe
Q5: The setting sun appears red because its
Q6: The less the mass of a main-sequence
Q13: The two most abundant elements in the
Q20: In the first 3 s after a
Q24: The oxygen in the earth's atmosphere comes
Q34: Ionic crystals dissolve only in liquids that
Q44: The 2.5-kg head of an ax exerts
Q58: When 90 kJ is removed from