Question 67Safety & Environmental - Assistant Engineer

The correct answer is A) vapor density. The vapor density of a material refers to the relative weight of the vapor compared to the weight of an equal volume of air. This physical data term on a Material Safety Data Sheet (MSDS) indicates whether the vapor formed by a material is lighter or heavier than air. A vapor density greater than 1 means the vapor is heavier than air and will tend to sink, while a vapor density less than 1 means the vapor is lighter than air and will tend to rise. The other options are incorrect because they do not directly indicate whether the vapor is lighter or heavier than air. Vapor pressure measures the tendency of a material to evaporate, vapor level refers to the concentration of the vapor, and vapor gravity is not a standard physical data term found on an MSDS.