Unfortunately your question is redundant; matter causes mass.
The answer is that the smallest unit would be any subatomic particle (proton, antiproton, Tau, muon, and even an electron but only slightly). Then there are atoms and other than that, diatomic molecules (normal matter or dark matter) would be next.
No, one ton would not float in outer space because weightlessness in space is due to the absence of gravity, not because of buoyant forces. In space, objects with mass will still have weight but will appear weightless due to the lack of a gravitational force pulling them down.
Your mass is the amount of matter that contains, it is your weight that will differ due to gravity. The astronaut still has the same amount of matter whether he be on earth, in space, or on the moon, though due to the different strenghts of gravity he will weight the most on earth, 1/6th of this on the moon, and be weightless in outer space.
matter
an object
Yes, dust is matter. Matter is anything that has mass and takes up space, and dust particles fit this definition. Dust is composed of tiny solid particles that can be made up of various materials such as skin cells, pollen, and soil.
Matter does.
the amount of matter in a given space; mass per unit volume
Zero is not correct. Your weight may be zero in parts of space, but not in others. Weight, however, is a different thing altogether to mass and it is important not to confuse the two. Mass is the amount of matter in an object and this remains the same.
Your mass would still be 158 pounds in outer space. Mass is a measure of the amount of matter in an object and does not depend on gravity. Your weight, on the other hand, would be different in outer space because weight is the force of gravity acting on an object's mass.
Matter does have mass regardless of whether it occupies space or not. Mass is a fundamental property of matter that determines its inertia and gravitational interactions. Even if matter is compressed into a small volume where it occupies less space, it still possesses mass.
Matter occupies space and has mass.
Yes, mass is a intrinsic property of matter that is constant regardless of where the object is located. The mass of an object remains the same whether it is on Earth, the Moon, or in outer space.
All matter 1) has mass and 2) occupies space (has volume).
Matter
That which occupies space and has mass is known as matter.
Matter has mass and occupies physical space, whereas energy does not have mass and does not occupy physical space.
Matter occupies space and has mass. Matter is made up of particles that have volume and hence occupy space. Mass is a measure of the amount of matter in an object, and it is related to the number and type of particles that compose the object.