Concentration of Mass

Answer each question by clicking the correct blue button. Only the first answer selected is graded.

1.  Two chemicals with a combined mass of 140.2g react in a flask. The mass of the products is 137.2g. A gas is produced from the reaction. What was the mass of the gas produced?
A. 140.2g.
B. 137.2g.
C. 3.0 g.
D. 277.4g.

2.  Which of the following equations correctly shows the conservation of mass?
A. HgO---> Hg + O2.
B. BaSO4 + C ---> BaS + CO .
C.H2SO4 + 2KOH---->K2SO4 + 2H2O.
D. NiCl2 + 2NaOH---->Ni(OH)2 + NaCl.

3.  How many atoms are contained in the following chemical formula? 2AgNO3

A. 3.
B. 10.
C. 5.
D. 2.

4.  How many atoms are found on each side of the following chemical equation?

H2SO4 + 2KOH----->K2SO4 + 2H2O:


A. 13.
B. 14.
C. 10.
D. 6.

5.  Fred performed an experiment in which he combined Aluminum Oxide with Carbon. The mass of the AL2O3 and C together was 5.2 g. The reaction produced Aluminum and Carbon Dioxide. The solid products had a combined mass of 5.0 g. There was a difference between the measured 5.2 g of the reactants and the measured 5.0 g of the products because…

A. Some of the mass escaped into the air as a gas.
B. Mass was lost and cannot be recovered.
C. The mass of the products in a reaction is not equal to the mass of the reactants.
D. The reaction was not complete.


Grade exam.