Which condition must be met in order for an equation to be balanced?
A. The elements in the reactants are the same as the elements in the products.
B. There are fewer elements in the reactants than there are in the products.
C. The number of atoms in the reactants is greater than the number of atoms in the products.
D. The number of atoms in the reactants equals the number of atoms in the products.
Answer (2)
A balanced equation requires the same elements on both sides.
The number of atoms of each element must be the same in reactants and products.
This ensures mass is conserved during the reaction.
Therefore, the number of atoms in the reactants equals the number of atoms in the products: T h e n u mb ero f a t o m s in t h ere a c t an t se q u a l s t h e n u mb ero f a t o m s in t h .
Explanation
Understanding Balanced Equations To determine the condition for a balanced equation, we need to understand what it means for an equation to be balanced in the context of chemistry. A balanced equation is one where the number of atoms of each element is the same on both sides (reactants and products). This ensures that mass is conserved during a chemical reaction, adhering to the law of conservation of mass.
Analyzing the Options Let's analyze the options:
The elements in the reactants are the same as the elements in the products: This is true for any chemical reaction, balanced or not. The same elements must be present on both sides.
There are fewer elements in the reactants than there are in the products: This is incorrect. The number of elements must remain constant.
The number of atoms in the reactants is greater than the number of atoms in the products: This is incorrect. In a balanced equation, the number of atoms of each element must be equal on both sides.
The number of atoms in the reactants equals the number of atoms in the products: This is the correct condition.
Conclusion Therefore, the correct condition for a balanced equation is that the number of atoms in the reactants equals the number of atoms in the products.
Examples
In baking, a balanced equation is like a recipe. If you want to bake a cake, you need the right amount of ingredients (reactants) to get the desired cake (product). If you have too much of one ingredient or not enough of another, the cake won't turn out right. Similarly, in chemistry, a balanced equation ensures that you have the right amount of each element to form the desired compound without any leftover or missing atoms.
For an equation to be balanced, the number of atoms in the reactants must equal the number of atoms in the products. This ensures that mass is conserved throughout the chemical reaction. Therefore, the correct choice is D.
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