Question

quiz 8.6be- counting atoms, chemical equations and the law of conservation of mass 4 of 10
possible points: 12.5
what is shown by this balanced chemical equation?
$ce{h_{2} + cl_{2} -> 2hcl}$
select three answers.
$square$ the total number of atoms changes in the reaction.
$square$ the product is a new substance made up of different atoms than the reactants.
$square$ the same atoms are present before and after the reaction.
$square$ matter is neither created or destroyed in the reaction. matter is conserved.
$square$ the atoms in the original substances rearrange and form a different substance

Explanation:

1. Analyze "The total number of atoms changes in the reaction": In a balanced chemical equation, the total number of atoms of each element is the same before and after the reaction. For \(H_2 + Cl_2

ightarrow 2HCl\), reactants have 2 H and 2 Cl atoms, products also have 2 H (from 2HCl) and 2 Cl (from 2HCl) atoms. So this statement is false.

1. Analyze "The product is a new substance made up of different atoms than the reactants": Reactants are \(H_2\) (H atoms) and \(Cl_2\) (Cl atoms), product is HCl (H and Cl atoms). So the product has the same types of atoms as reactants. This statement is false.
2. Analyze "The same atoms are present before and after the reaction": Reactants have H and Cl atoms, products (HCl) also have H and Cl atoms. So same atoms are present. This statement is true.
3. Analyze "Matter is neither created or destroyed in the reaction. Matter is conserved": The law of conservation of mass states that matter is conserved in a chemical reaction (balanced equation shows equal number of each atom on both sides, so mass is conserved as mass of an atom is constant). This statement is true.
4. Analyze "The atoms in the original substances rearrange and form a different substance": In the reaction, \(H_2\) and \(Cl_2\) (original substances) rearrange their atoms to form HCl (a different substance). This statement is true.

Answer:

• The same atoms are present before and after the reaction.
• Matter is neither created or destroyed in the reaction. Matter is conserved.
• The atoms in the original substances rearrange and form a different substance.