Question

Hydrogen peroxide, H₂O₂, is a water-soluble compound. The concentration of an aqueous hydrogen peroxide solution that is 3% by mass H₂O₂ is used as an antiseptic. When the solution is poured on a small cut in the skin, H₂O₂ reacts according to the balanced equation below.

2H₂O₂ ==> 2H₂O + O₂
1. Identify the type of chemical reaction represented by the balanced equation.
2. Calculate the total mass of H₂O₂ in 20.0 grams of an aqueous H₂O₂ solution that is used as an antiseptic. Your response must include both a numerical setup and the calculated result.

Answer 1

The balanced equation represents a decomposition reaction, and the mass of H₂O₂ in a 3% solution can be found by multiplying the total mass of the solution (20.0 grams) by 0.03, resulting in 0.6 grams of H₂O₂.

Step-by-step explanation:

The chemical reaction represented by the balanced equation 2H₂O₂ ⇒ 2H₂O + O₂ is a decomposition reaction because one compound breaks down into two or more products.

Calculating the total mass of H₂O₂ in 20.0 grams of a 3% aquous H₂O₂ solution involves finding 3% of the solution's mass, since '3% by mass' means that 3 grams of hydrogen peroxide are present in every 100 grams of the solution. Therefore, to find the mass of H₂O₂, you can set up the calculation as follows:

Multiply the total mass of the solution by the percentage (expressed as a decimal) of H₂O₂.\
\
\Mass of H₂O₂ = total mass of solution × mass percentage of H₂O₂\
\= 20.0 grams × 0.03\
\= 0.6 grams

The total mass of H₂O₂ in 20 grams of a 3% aqueous solution is 0.6 grams.

Answer 2

1) Decomposition Reaction

2) 0.6 g H₂O₂

Step-by-step explanation:

The reaction that takes place is:

2H₂O₂ → 2H₂O + O₂

1) Because one component is broken into two or more products, this is a Decomposition reaction.

2) The concentration of H₂O₂ is 3% by mass, so the total mass of H₂O₂ in 20.0 g of a solution is:

20.0 * 3/100 = 0.6 g H₂O₂