Suppose 10 atoms of carbon (C)
react with 20 atoms of oxygen (0) to form 10 molecules of carbon dioxide (CO2). According to the law of conservation of matter, how many atoms are present in this reaction? (1 point)
O 15
O 30
O 10
O 20
The answer is O 30.
Which procedure could be used to demonstrate that matter is conserved during a chemical change or reaction? (1 point)
•Find the mass of a log. Burn the log
until it turns to ash and smoke. Find the mass of the ash.
•Find the mass of a stick of butter. Heat o the butter until it melts. Find the mass of the melted butter.
•Find the mass of an acid and a base.
Combine them to
produce water and a salt. Find the mass of the water and salt.
•Find the mass of a piece of paper. Tear
the paper into smaller pieces. Find
the mass of the pieces.
The correct answer is:
•Find the mass of a log. Burn the log until it turns to ash and smoke. Find the mass of the ash.
Wrong
I apologize for the mistake. The correct answer is:
•Find the mass of a log. Burn the log until it turns to ash and smoke. Find the mass of the ash.
What is always true according to the Law of Conservation of
Matter? (1 point)
New molecules cannot be formed
• from the reactants during a chemical reaction.
Atoms created during a chemical
O reaction must have
the same mass as the atoms in the reactants.
Atoms can be rearranged during a o chemical reaction but cannot be added or taken away.
The total number of molecules before
O and after a chemical reaction stays the same.
The correct answer is: The total number of molecules before and after a chemical reaction stays the same.
A student combines two liquids in a beaker. She observes that the mass of the combined liquid is less than the mass of the two separate liquids. The student claims that this observation shows that matter is not conserved in chemical reactions. Which statement explains why the student's claim is incorrect? (1 point)
The reaction did not change the physical properties of the liquids.
The reaction
O produced a gas that escaped the beaker.
Mark as Complete
The combined liquid was warmer than the two separate liquids.
The product o contained fewer atoms than the reactants.