Why is a new flu vaccine made every year?

1)each group 16 element has how many valence electrons? ( )4 ( )6 ( )8 ( )16 2)how many dots appear in the dot structure for calcium ion, ca2+? ( )zero ( )one ( )two ( )eight 3) which of the following atoms forms a cation to obtain an octet of outer shell electrons? ( )magnesium ( )oxygen ( )fluorine ( )helium 4) an al3+ ion contains 13 protons and 10 electrons. ( )true ( )false 5) valence and non-valence electrons are represented in lewis dot structures. ( )true ( )false

The following reaction shows the products when sulfuric acid and aluminum hydroxide react. al(oh)3 + h2so4 → al2(so4)3 + h2o the table shows the calculated amounts of reactants and products when the reaction was conducted in a laboratory. sulfuric acid aluminum hydroxide initial amount of reactant 40 g 15 g theoretical yield of water from reactant 14.69 g 10.38 g what is the approximate amount of the leftover reactant? 11.73 g of sulfuric acid 10.33 g of sulfuric acid 11.12 g of aluminum hydroxide 13.67 g of aluminum hydroxide

Someone offer some answers to this, i will give 98 coins and mark as brainliest! i will put the rest of the lab down in the comments,solutions pre-lab questions: in this lab, you will make fruit drinks with powdered drink mix. complete the pre-lab questions to get the values you need for your drink solutions. calculate the molar mass of powered fruit drink mix, made from sucrose (c12h22o11).using stoichiometry, determine the mass of powdered drink mix needed to make a 1.0 m solution of 100 ml. (hint: use molarity = to find the moles of drink mix, then convert moles to grams using a mole conversion.)what mass of powdered drink mix is needed to make a 0.5 m solution of 100 ml?