Yes
That would depend on the buoyancy of the feathers.
That depends on the substance being measured. Lead will weigh more than feathers.
Because of its' mass density. The lead would be much smaller in size.
The "kilogram" is a unit of mass. Every kilogram has the same mass, no matterof what substance.The question is much like asking: "Which is longer, a mile in a car or a mile on a bicycle ?"
One kilogram of brick weighs as much as one kilogram of feathers. (I do not know what a "chesse of feathers" is...)
It takes alot more feathers to equal a kilogram than it does bricks
Sand is denser than feathers. Since a given volume of a denser material has more mass than the same volume of a less dense material, when you make the masses the same, the volumes must vary.
One Kilogram
The density of a material is defined as its mass per unit volume. A given volume of lead has more mass than a given volume of feathers. In common usage mass often refers to weight, but that is not a very exact usage of it. For this question it may be useful however to think of a given weight of lead per volume and a given weight of feathers.If you have a kg of lead, that is a small piece, a kg of feathers is a large amount.So for a given volume, say a cubic centimeter, the weight of lead is much more than the weight of feathers.
lead has much higher density
1 kilogram
the densities are different