According to the law of conservation of mass, how does the mass of the products in a chemical reaction compare to the mass of the reactants? a there is no relationship. b the mass of the products is sometimes greater. c the mass of the reactants is greater. d the masses are always equal.

a gas, having a molecular weight of 13 kg/kmol and a kinematic viscosity of 0.25 cm2/s, flows through a pipe 0.25 m internal diameter and 5 km long at the rate of 0.4 m3/s and is delivered at atmospheric pressure.

qualitative observation deals with data that can be observed with our senses: sight, smell, touch, taste, and hearing. they do not involve measurements or numbers. for instance, colors, shapes, and textures of objects are all qualitative observations.