As part of an investigation, students combined substances in a beaker to observe chemical reactions. They performed two procedures. They measured the mass of
each substance before and after each reaction. The table shows their observations.
Mass of Products
Procedure
97.59
Procedure 2
102.50
Procedure 1: All the reactants were liquids that evaporated.
Procedure 2: A gas was formed as one product, and it escaped into
the air
Mass of Reactants
100.0 9
100.00
Procedure 1: One of the reactants was converted to thermal
energy,
Procedure 2: All the products were liquids.
e
Assuming the students did not make any careless errors, what likely explains these
changes in mass?
Procedure 1: The reactants were liquids with different densities.
Procedure 2: The reactants were combined into only one product.
e
air.
Procedure 1: One of the products was a gas that escaped into the
Procedure 2: A gas from the air reacted with one of the other
reactants and formed a precipitate.
CLEAR ALL