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

Question

Responses

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

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

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

CH4 + O2 → CO2 + 2H2O

Answer 1

To determine which chemical equation has the same number of atoms in the reactants as in the products, we can balance each equation by counting the number of each type of atom on both sides.

1. Li2CO3 → LiO + CO2

   • Reactants: 2 Li, 1 C, 3 O (Total = 6 atoms)
   • Products: 1 Li, 1 C, 2 O (Total = 4 atoms)
   • Not balanced.

2. CO2 + H2O → CH2OH + O2

   • Reactants: 1 C, 2 O (from CO2), 2 H, 1 O (from H2O) (Total = 6 atoms)
   • Products: 1 C, 6 H, 3 O (Total = 10 atoms)
   • Not balanced.

3. Zn + 2HCl → H2 + ZnCl2

   • Reactants: 1 Zn, 2 H, 2 Cl (Total = 5 atoms)
   • Products: 1 Zn, 2 H, 2 Cl (Total = 5 atoms)
   • Balanced.

4. CH4 + O2 → CO2 + 2H2O

   • Reactants: 1 C, 4 H, 2 O (Total = 7 atoms)
   • Products: 1 C, 4 H, 3 O (Total = 8 atoms)
   • Not balanced.

The only balanced equation in which the number of atoms in the reactants is the same as in the products 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.

Answer 3

The correct statement regarding a chemical reaction, based on the law of conservation of mass, is:

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

This statement reflects the principle that in a chemical reaction, the total mass of the reactants equals the total mass of the products, as long as the reaction is conducted in a closed system where no mass is lost to the surroundings.

Answer 4

Use the equation and the table to answer the question.

FeCl3 + 3H2O → Fe(OH)3 + 3HCl

Element Mass of an Atom (amu)
Fe 56
Cl 35
H 1
O 16
Iron chloride and water react according to the equation shown. The table shows the atomic masses of the elements involved in the reaction. What is the total mass of the reactants?

(1 point)
Responses

108 amu
108 amu

215 amu
215 amu

161 amu
161 amu

179 amu
179 amu
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Answer 5

To find the total mass of the reactants for the reaction:

\[ \text{FeCl}_3 + 3\text{H}_2\text{O} \]

we need to calculate the mass of each component in the reactants.

1. Calculating the mass of \( \text{FeCl}_3 \):

   • 1 Fe = 56 amu
   • 3 Cl = 3 × 35 amu = 105 amu
   • Total mass of \( \text{FeCl}_3 = 56 + 105 = 161 \) amu

2. Calculating the mass of \( 3\text{H}_2\text{O} \):

   • Each \( H_2O \) has:
     • 2 H = 2 × 1 amu = 2 amu
     • 1 O = 16 amu
     • Total mass of \( \text{H}_2O = 2 + 16 = 18 \) amu
   • For 3 \( \text{H}_2\text{O} \):
     • Total mass = \( 3 × 18 = 54 \) amu

3. Total mass of the reactants:

   • Total mass = Mass of \( \text{FeCl}_3 + \text{mass of } 3\text{H}_2\text{O} \)
   • Total mass = \( 161 , \text{amu} + 54 , \text{amu} = 215 , \text{amu} \)

Thus, the total mass of the reactants is 215 amu.

Answer 6

In a chemical reaction, two molecules with a total mass of 76 amu react to form a single molecule. What is the mass of the molecule that is formed?(1 point)
Responses

228 amu
228 amu

152 amu
152 amu

76 amu
76 amu

38 amu

Answer 7

In a chemical reaction, the law of conservation of mass states that mass is neither created nor destroyed. Therefore, the total mass of the reactants must equal the total mass of the products.

Given that the two molecules have a total mass of 76 amu, this means that the mass of the single molecule that is formed as a product will also be 76 amu.

Thus, the correct answer is:

76 amu.