1) Roseanne and D'Asia were asked to design and create a paper airplane that would stay in the
air for as long as possible. They began by folding printer paper into four different planes. They
then tested the flying times of the planes by throwing them and timing their flights with a
stopwatch. They compared results and selected the plane with the longest time as their best
design
Which is their independent variable?
A) the time the planes stayed in the air
C) the type of paper used
B) the design of the plane
D) the number of times they threw

The two naturally occurring isotopes of chlorine are 35cl (34.969 amu, 75.77%) and 37cl (36.966 amu, 24.23%). the two naturally occurring isotopes of bromine are 79br (78.918 rm amu, 50.69%) and 81br (80.916 amu, 49.31%). chlorine and bromine combine to form bromine monochloride, brcl. 1. how many peaks will be present in a mass spectrum for brcl? the four combinations of molecule possible given these four isotopes are: 81br37cl, 81br35cl, 79br37cl, and 79br35cl. 2. what are the masses of the four different brcl molecules? express the masses using six significant figures, in decreasing numeric order (highest to lowest), separated by commas.