1
In a chemical reaction, what fundamental principle explains why the total mass remains constant?
Atoms are rearranged but not lost
In the chemical formula Ca(OH)₂, how many oxygen atoms are present?
2
What does the prefix 'di-' typically indicate in a chemical formula?
Two of an element
Describe what happens to atoms during a chemical reaction. Do they disappear, or do they rearrange? Explain.
Atoms do not disappear; they rearrange to form new substances. The same atoms are just combined in new ways.
In the chemical formula H₂O, how many hydrogen and oxygen atoms are present?
2 hydrogen, 1 oxygen
What is a chemical reaction, and what is one sign that a chemical reaction has taken place?
A chemical reaction is when substances change into new substances. Signs include color change, temperature change, gas bubbles, light production, or formation of a solid.
What is a coefficient in a chemical equation?
A number placed in front of a chemical formula that shows how many molecules are involved
Which reaction type involves a single compound breaking down into two or more simpler substances?
Decomposition reaction
Which reaction involves direct element exchange?
Replacement reaction
What indicates that a chemical reaction has occurred?
New properties emerge
What determines whether a chemical reaction occurs?
Changes in substance properties
Which type of reaction involves two or more substances combining to form a single new substance?
Synthesis reaction
How do atoms behave during a chemical reaction?
They are rearranged
What happens to atoms during a chemical reaction?
Atoms are rearranged into new configurations
What makes synthetic materials different from natural materials?
They are processed from natural resources
What happens to the number of atoms before and after a chemical reaction?
Total number of atoms remains constant
What principle explains why the mass remains constant in reactions?
Atoms are conserved
Which factor can indicate a chemical reaction has occurred?
Color change
In a chemical reaction, energy can be:
Absorbed or released
What characterizes a chemical reaction?
Formation of new substances with different properties
In a replacement reaction, what occurs between elements?
One element replaces another in a compound
In the formula NaCl, what elements are represented?
Sodium and Chlorine
Which statement best describes mass conservation in chemical reactions?
Atoms are rearranged but total mass remains constant
What environmental impact do synthetic materials often cause?
Pollution
How do synthetic materials typically originate?
Extracted from natural resources