2) B. Dependent Variable. This is because the rate of the algae growth depends on the other variables. 3) D 4) F 5) C 6) A 7) E 8) B
A. The number of valence electrons increases as atomic mass increases. == Generally true for the representative elements since atomic mass generally increases with increasing Z.
B. The reactivity of alkali metals increases as atomic mass increases. == True. Atomic mass increases down the column and so does reactivity
C. The reactivity of the halogens increases as atomic mass increases. == False. Reactivity decreases down the column.
D. The number of valence electrons decreases across a period. == False. In general, the number of valence electrons increases across a period, particularly for the representative elements.
The clean air act of 1990 was important because it helped reduce pollution and keep the enviornment safe. The act organized the idea's of 'safe' in regards to the ozone layer and also the air (generally). This meant that the amount of acid rainfall was controlled. It set rules and policies regarding polluting. Basically, people needed to wake up and think about the enviornment. Companies, people, and even communities were all now responsible for keeping what they breathe (air) clean.
Does this explain it pretty well? If not, please feel free to comment! Thanks for being part of Brainly. :)
Chemical science deals with mater like compound mater
