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

Question

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 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.

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 changes, so mass is conserved in the reaction.

Answer 1

The true statement regarding a chemical reaction is:

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

This reflects the law of conservation of mass, which states that in a closed system, the mass of the reactants must equal the mass of the products, as atoms are neither created nor destroyed during a chemical reaction.

Answer 2

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

179 amu
179 amu

108 amu
108 amu

161 amu
161 amu

215 amu
215 amu

Answer 3

To find the total mass of the reactants in the reaction \( \text{FeCl}_3 + 3\text{H}_2\text{O} \), we need to calculate the mass of each reactant based on the given atomic masses and then sum them up.

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

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

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

   • Hydrogen (H) = 6 × 1 amu = 6 amu (since there are 2 H in each H2O and we have 3 H2O)
   • Oxygen (O) = 3 × 16 amu = 48 amu
   • Total mass of \( 3\text{H}_2\text{O} \) = 6 amu + 48 amu = 54 amu

3. Total mass of reactants:

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

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

Answer 4

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

76 amu
76 amu

152 amu
152 amu

228 amu
228 amu

38 amu

Answer 5

In a chemical reaction, the law of conservation of mass states that the total mass of the reactants must equal the total mass of the products.

Since the two molecules have a total mass of 76 amu, the mass of the single molecule that is formed must also be 76 amu.

Thus, the answer is:

76 amu.