a sample of bromine was analysed in a time of flight (tof) mass spectrometer and
found to contain two isotopes, 79br and 81br
after electron impact ionisation, all of the lons were accelerated to the same
kinetic energy (ke) and then travelled through a flight tube that was 0.950 m long.
the 79br+ lons took 6.69 x 10^-4 to travel through the flight tube.
calculate the mass, in kg, of one lon of 79br+
calculate the time taken for the 81br+ ions to travel through the same flight tube.
the avogadro constant, l = 6.022 x 10mol!
ke = 5 roy? where m = mass (kg) and v= speed (m 3-')
where d = distance (m) and t = time (s)
(5 marks)

Wind will blow from one direction to another.

257 grams h2o i think

Vander waals forces are inter molecular bonds that exist within molecules of the same substance. a water molecule is made up of oxygen and hydrogen atoms which share electrons between each other. the vander waals forces are forces that exist between multitude of different  molecules of water. dipole dipole forces is the type of vander waals force that exist in water. the oxygen atom which is more electronegative pulls the shared electron closer to itself thus generating a partial negative charge while the hydrogen acquire a partial positive charge. these two different charges causes attraction to occur in water molecules.