20.What do carbon and silicon have in common? a. They belong to the same column (family), therefore they have the same number of valence electrons.
b. They belong to the same column (family), therefore they have the same number of total electrons.
c. They belong to the same column (family), therefore they have the same number of energy levels.
d. They belong to the same column (family), therefore they have the same number of protons.

Select all of the methods through which a drug can enter your body. injection swallowing inhalation absorption

To calculate percent by mass, use the equation below: calculate the percent by mass of each element. %n = % %h = % %o = %

There are two steps in the usual industrial preparation of acrylic acid, the immediate precursor of several useful plastics. in the first step, calcium carbide and water react to form acetylene and calcium hydroxide: cac2 (s) + 2h2o (g) → c2h2 (g) + caoh2 (s) =δh−414.kj in the second step, acetylene, carbon dioxide and water react to form acrylic acid: 6c2h2 (g) + 3co2 (g) + 4h2o (g) → 5ch2chco2h (g) =δh132.kj calculate the net change in enthalpy for the formation of one mole of acrylic acid from calcium carbide, water and carbon dioxide from these reactions. round your answer to the nearest kj .