How to calculate the mass of a rectangular solid that has a density of 3.24g/cm3 and measures 2.50cm by 1.80cm by 3.00?

space exploration has led to the development and technological improvement of many everyday items. (if this answer is wrong i will find the right answer) : )

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.

> b takes place in the gas phase in an isothermal tubular reactor. the feed is one mole of a per one mole of c, an inert. the entering temperature and pressure are 427°c and 10 atm, respectively. the gas constant r = 0.08206 atm · l/mol · k.