A catalyst is a chemical that increases the rate of a chemical reaction without itself being changed by the reaction. The fact that they aren't changed by participating in a reaction distinguishes catalysts from substrates, which are the reactants on which catalysts work. Enzymes catalyze biochemical reactions.
B I hope it’s right I don’t really help a lot but yeah lol
Find volume of pillow
L=78cm
B=55cm
H=25cm




Now
Mass=5.5kg



Density of water=1000kg/m^3
As it is less than density of water it will float on water