Help, timed assignment

He table below gives the atomic mass and relative abundance values for the three isotopes of element m. relative abundance (%) atomic mass (amu) 78.99 23.9850 10.00 24.9858 11.01 25.9826 what is the average atomic mass (in amu) of element m? 2.86 5.36 24.30 24.98

Before it was launched, a helium-filled balloon had a pressure of 201 kpa at a temperature of 27°c. at an altitude of 15,000 m, the pressure had decreased to 2.5 kpa and the temperature had dropped to -14 °c. the volume of the balloon increased to 59.3 m3. what is the original volume of the balloon? 13 m3 0.85 m3 0.077 m3 1.17 m3

How many atoms are in 2 moles of phosphorus?