naturally occurring thallium consists of two stableisotopes, tl-203 and tl-205 (atomic masses = 203.0 and205.0, respectively) and has an average atomic mass of204.4. what is the percentage of tl-205?

Often on a topographic map, every fifth contour line is darkened. what is this line called? a. key b.slope c.benchmark d. index contour

Draw any one of the skeletal structures of a 2° alkyl bromide having the molecular formula of c6h13br and two stereogenic centers. indicate chirality by using wedge and hashed wedge notation. lone pairs do not need to be shown.

In the reaction h2co3 (aq) + 3nh3 (aq) = 2 nh4+ (aq) + co3 2-, how many electrons are transferred?