In which chemical equation is the number of atoms in the reactants the same as the number of atoms in the products?(1 point)

Question

Responses

Li2CO3 → LiO + CO2
Li 2 CO 3 → LiO + CO 2

Zn + 2HCl → H2 + ZnCl2
Zn + 2HCl → H 2 + ZnCl 2

CO2 + H2O → CH2OH + O2
CO 2 + H 2 O → CH 2 OH + O 2

CH4 + O2 → CO2 + 2H2O
CH 4 + O 2 → CO 2 + 2H 2 O
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Answer 1

To determine which chemical equation has the same number of atoms of each element in the reactants and products, we can analyze each of the provided equations.

1. Li2CO3 → LiO + CO2

   • Reactants: 2 Li, 1 C, 3 O
   • Products: 1 Li, 1 O (from LiO) + 1 C, 2 O (from CO2)
   • Total in products: 1 Li + 1 C + 3 O
   • Total atoms: 2 in the reactants vs. 5 in the products (not balanced).

2. Zn + 2HCl → H2 + ZnCl2

   • Reactants: 1 Zn, 2 H, 2 Cl
   • Products: 1 Zn, 2 H, 2 Cl
   • Total in reactants = total in products = 5 atoms (balanced).

3. CO2 + H2O → CH2OH + O2

   • Reactants: 1 C, 2 O (from CO2) + 2 H, 1 O (from H2O)
   • Total in reactants = 1 C + 4 O + 2 H = 7 atoms
   • Products: 1 C, 2 H, 1 O + 2 O
   • Total atoms in products = 1 C + 2 H + 3 O = 6 atoms (not balanced).

4. CH4 + O2 → CO2 + 2H2O

   • Reactants: 1 C, 4 H, 2 O
   • Products: 1 C, 2 O + 4 H, 1 O
   • Total in reactants = 6 atoms vs. 6 atoms in products (balanced).

The only equation that has the same number of atoms in the reactants and products is Zn + 2HCl → H2 + ZnCl2.

Thus, the answer is: Zn + 2HCl → H2 + ZnCl2.

Answer 2

Which statement is true regarding a chemical reaction?(1 point)
Responses

Even if the total number of atoms does not change, mass may not be conserved in the reaction.
Even if the total number of atoms does not change, mass may not be conserved in the reaction.

The total number of atoms changes, so mass is conserved in the reaction.
The total number of atoms changes, so mass is conserved in the reaction.

Even if the total number of atoms changes, mass may not be conserved in the reaction.
Even if the total number of atoms changes, mass may not be conserved in the reaction.

The total number of atoms does not change, so mass is conserved in the reaction.
The total number of atoms does not change, so mass is conserved in the reaction.
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Answer 3

The true statement regarding a chemical reaction is:

The total number of atoms does not change, so mass is conserved in the reaction.

In a chemical reaction, atoms are rearranged but not created or destroyed, which means that the total mass of the reactants is equal to the total mass of the products. This principle is known as the law of conservation of mass. Therefore, the correct response emphasizes that while the arrangement of atoms may change, the total number of atoms (and hence mass) remains constant.