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Eighth Grade Science S8P1.f LP3.3

Last updated over 6 years ago

5 questions

Note from the author:

S8P1.f LP3.3

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Question 1

1.

A. The law of conservation of mass was broken in this experiment because the mass of the solid decreased. 

B. The law of conservation of mass was not broken because the mass before heating was greater than the mass after heating 

C. The law of conservation of mass was not broken because the solid was heated in an open container, allowing gases to escape. 

Question 2

2.

A.  that some of the mass was lost to the air as light 

B.  that mass has absolutely no relationship to matter 

C.  that some of the mass was lost to the air as smoke 

D.  that ash has a lower mass than the strip of magnesium 

Question 3

3.

A.  The total mass of the closed system is constant. 

B.  Energy is converted to mass when the candle is burned. 

C.  Smoke particles have less mass than the molecules of the candle. 

D.  The mass of the smaller candle has less   energy than the larger candle.

Question 4

4.

How can the law of conservation of mass apply to a burning log, if all that remains of it is ash?

A.  The ash has the same mass as the log, although a large percentage of it blows away. 

B.  The law of conservation of mass applies   to changes of state but not to chemical reactions.

C.  The law of conservation of mass applies to substitution and displacement reactions, but not to combustion reactions. 

Question 5

5.

Mariana conducted an experiment where she burned a 5 g strip of magnesium metal in an open flame. The result was a 3.5 g white ash collected in a crucible, a bright white flame, and smoke. Was the law of conservation of matter upheld in Mariana's experiment?

A.  yes, because the missing mass was trapped by the closed system 

B.  no, because the magnesium was burned so mass was not lost 

C.  no, because mass decreased after the magnesium was burned 

D.  yes, because the missing mass was released as smoke 

D. The law of conservation of mass was broken in this experiment because the solid was heated in an open container, allowing gases to escape. 

D.  The masses of the gases released into the air plus the mass of ash equal the mass of the log before burning. 