A magnesium ribbon of mass 4.0g is placed in a dilute hydrochloric acid contained in a beaker. calculate the number of moles of hydrochloric acid that will be required to react completely with the ribbon.(Mg=2400,Cl=35.5) solve ​

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