With RRMS, the patient experiences relapses (attacks, exacerbations, or flare-ups) during which there are increased symptoms and/or a worsening of neurologic function, followed by partial or complete recovery (or remission). Much more common: RRMS is much more common than progressive courses of MS, which only affect 10% to 15% of patients.
Vapor density is the density of a vapour in relation to that of hydrogen.It may be defined as mass of a certain volume of a substance divided by mass of same volume of hydrogen. vapor density = mass of n molecules of gas / mass of n molecules of hydrogen.Therefore:vapour density = molar mass of gas / molar mass of H 2.or example, acetone has a vapour density of 2 in relation to air. That means acetone vapour is twice as heavy as air. This can be seen by dividing the molecular weight of Acetone, 58.1 by that of air, 28.97, which equals 2.
Water Density. If you are still in school, you've probably heard the statement in the box to the right a number of times: Density Density is the mass per unit volume of a substance. On Earth, you can assume mass is the same as weight, if that makes it easier. If you're not still in school, then you probably forgot you ever even heard it. The definition of density, also known as specific gravity, makes a lot more sense with a little bit of explanation.