A. <span>Exposure to an antigen
Exposure to viruses and antigens led to the foundation of modern vaccination. Vaccination introduces an antigenic material that helps the ability of the immune system to adapt a specific pathogen, therefore leading to a long-term immunity.</span>
The balanced equation is
<span>8SO2 + 16H2S ----> 3S8 + 16H2O
</span>so
77g SO2 / 64g/mole = 1.203moles of SO2
<span>77g H2S / 34g/mole = 2.26moles of H2S
</span>now
<span>1.203 moles SO2 yields 3/8x amount that is = 0.456moles of S8
</span>so
<span>2.06moles H2S yields 3/16x amount = 0.386moles of S8
</span>hence
H2S = produce only 0.386moles of S8 = 98.98g S8
hope it helps
