The variable that we change or test in an experiment is called the A) Dependent variable
B) Independent variable
C) Constant

Fission of uranium-235 products energy and a. isotopes of smaller elements b. isotopes of larger elements c. lighter isotopes of uranium d. heavier isotopes of uranium

What are the three major branches of natural science? • earth and space science, life science, physical science •earth and space science, physical science, chemistry •physical science, life science, chemistry •life science, chemistry, physics

Modern pennies are composed of zinc coated with copper. a student determines the mass of a penny to be 2.482 g and then makes several scratches in the copper coaling (to expose the underlying zinc). the student puts the scratched penny in hydrochloric acid, where the following reaction occurs between the zinc and the hcl (the copper remains undissolved): zn(s) + 2 hcl(aq) → h2(g) + zncl(aq)the student collects the hydrogen produced over water at 25 °c. the collected gas occupies a volume of 0.899 l at a total pressure of 79 j mmhg. calculate the percent zinc (by mass) in the penny. (assume that all the zn in the penny dissolves.)