Compare the total mass of the reactants to the total mass of the products. What choice demonstrates the Law of Conservation of Mass?
[tex]$248 g AgO \rightarrow 216 g Ag +32 g O _2$[/tex]
[tex]$95 g CaCO _3 \rightarrow 56 g CaO +44 g CO _2$[/tex]
[tex]$30 g Li _2 O +44 g CO _2 \rightarrow 78 g Li _2 CO _3$[/tex]
[tex]$81 g HNO _3 \rightarrow 46 g NO _2+32 g O _2+18 g H _2 O$[/tex]
Answer (2)
The Law of Conservation of Mass states that the total mass of reactants equals the total mass of products in a chemical reaction.
Calculate the total mass of reactants and products for each reaction.
Compare the masses to see which reaction obeys the law.
The first reaction, 248 g A g O → 216 g A g + 32 g O 2 , demonstrates the Law of Conservation of Mass because 248 g = 216 g + 32 g . 248 g A g O → 216 g A g + 32 g O 2
Explanation
Understanding the Law of Conservation of Mass The Law of Conservation of Mass states that in a closed system, mass is neither created nor destroyed during a chemical reaction. This means the total mass of the reactants must equal the total mass of the products. We need to check each reaction to see which one obeys this law.
Analyzing the First Reaction Let's analyze the first reaction: 248 g A g O → 216 g A g + 32 g O 2 . The total mass of the reactant (AgO) is 248 g. The total mass of the products (Ag and O 2 ) is 216 g + 32 g = 248 g . Since the mass of the reactants equals the mass of the products, this reaction demonstrates the Law of Conservation of Mass.
Analyzing the Second Reaction Now, let's check the second reaction: 95 g C a C O 3 → 56 g C a O + 44 g C O 2 . The total mass of the reactant ( C a C O 3 ) is 95 g. The total mass of the products (CaO and C O 2 ) is 56 g + 44 g = 100 g . The masses are not equal, so this reaction does not demonstrate the Law of Conservation of Mass.
Analyzing the Third Reaction Let's analyze the third reaction: 30 gL i 2 O + 44 g C O 2 → 78 gL i 2 C O 3 . The total mass of the reactants ( L i 2 O and C O 2 ) is 30 g + 44 g = 74 g . The total mass of the product ( L i 2 C O 3 ) is 78 g. The masses are not equal, so this reaction does not demonstrate the Law of Conservation of Mass.
Analyzing the Fourth Reaction Finally, let's analyze the fourth reaction: 81 g H N O 3 → 46 g N O 2 + 32 g O 2 + 18 g H 2 O . The total mass of the reactant ( H N O 3 ) is 81 g. The total mass of the products ( N O 2 , O 2 , and H 2 O ) is 46 g + 32 g + 18 g = 96 g . The masses are not equal, so this reaction does not demonstrate the Law of Conservation of Mass.
Conclusion Only the first reaction, 248 g A g O → 216 g A g + 32 g O 2 , demonstrates the Law of Conservation of Mass because the total mass of the reactants (248 g) equals the total mass of the products (248 g).
Examples
The Law of Conservation of Mass is crucial in many real-world applications. For example, in pharmaceutical manufacturing, it ensures that the mass of the ingredients used to create a drug equals the mass of the final product. This verification is essential for quality control and regulatory compliance. Similarly, in environmental science, tracking the mass of pollutants in a closed system helps scientists understand their fate and impact, ensuring accurate environmental modeling and effective pollution control strategies. Understanding this law helps in accurately predicting and controlling outcomes in various scientific and industrial processes.
The first reaction, 248 g A g O → 216 g A g + 32 g O 2 , demonstrates the Law of Conservation of Mass because the total mass of the reactants equals the total mass of the products (248 g = 248 g). The other reactions do not meet this requirement. Thus, the chosen option is the first reaction.
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