A chemical reaction is shown. SnO2 + H2 - Sn + H20
What is true about this chemical reaction?
O A. It is unbalanced because the mass of the reactants is less than the mass of the products.
OB. It is balanced because the mass of the reactants is equal to the mass of the products.
O C. It is balanced because the number of reactants is equal to the number of products.
O D. It is unbalanced because the mass of the reactants is greater than the mass of the products.

the old alchemists made significant contributions to science even though there starting premises were off a bit. their conclusions after failure would steer them into better directions for investigation. science is no more than close observation and the initial mistakes result in rethinking and retrying experiments.

distance, luminosity, brightness, radius, chemical composition, and temperature

answers: to make sure that all of the broken pieces of tablet were added to the water, to allow for fair comparison of all three trials, with different particle sizes to avoid experimental error