" $Na _2 SO _3$ " represents sodium sulfite. What does the 4 mean in the formula $4 Na _2 SO _3$ ? A. There are four atoms of sodium. B. There are four atoms of sodium sulfite. C. There are four molecules of sodium sulfite. D. There are four elements in sodium sulfite.
Answer (1)
The coefficient 4 in the formula 4 N a 2 S O 3 indicates the number of sodium sulfite molecules.
The number 4 represents that there are four molecules of sodium sulfite.
Therefore, the correct interpretation is that there are four molecules of sodium sulfite.
The final answer is: There are four molecules of sodium sulfite.
Explanation
Understanding the Problem The formula " N a 2 S O 3 " represents sodium sulfite. The question asks what the number 4 means in the formula 4 N a 2 S O 3 . We need to choose the correct interpretation from the given options.
Explanation The number 4 in front of the chemical formula N a 2 S O 3 indicates that there are 4 molecules of sodium sulfite. This is similar to how in algebra, 4 x means 4 times x .
Conclusion Therefore, the correct answer is: There are four molecules of sodium sulfite.
Examples
In chemistry, understanding the coefficients in front of chemical formulas is crucial for balancing chemical equations. For example, in the reaction 2 H 2 + O 2 r i g h t a rro w 2 H 2 O , the '2' in front of H 2 means that two molecules of hydrogen react with one molecule of oxygen to produce two molecules of water. This concept is vital for calculating the amounts of reactants and products in chemical reactions, which has applications in various fields such as medicine, environmental science, and materials science.
