Question

foamy chemistry
sergio watches a video of a chemistry demonstration. in the video, a scientist pour
then, the scientist adds food coloring, detergent, and potassium iodide. immediate
substances, foam shoots out from the top of the flask! the foam goes all over the
scicntist explains that the foam is very hot.
sergio learns that this chemical reaction only involves hydrogen peroxide. figure 1
reaction in the flask.
figure 1: hydrogen peroxide chemica

figure 2 below shows the mass of the substances used during this demonstration.
what does figure 2 show?
a hydrogen peroxide was consumed in the chemical reaction
b potassium iodide was consumed in the chemical reaction.
c the chemical reaction converted hydrogen peroxide into potassium
iodide.
d the chemical reaction converted potassium iodide into hydrogen
peroxide.

Explanation:

• In a chemical reaction, the mass of reactants is related to their consumption.
• Potassium iodide acts as a catalyst (it is not consumed in the reaction as its mass remains unchanged in a catalytic role).
• The reaction is about hydrogen peroxide decomposition.
• Option B is wrong as potassium iodide is a catalyst (not consumed). Option C and D are wrong as the reaction is \(2H_2O_2

ightarrow 2H_2O + O_2\) (no conversion between \(H_2O_2\) and \(KI\)). Hydrogen peroxide is the reactant that is consumed.

Answer:

A. Hydrogen peroxide was consumed in the chemical reaction.