When using motion maps we can describe the motion of and as moving in a positive or a negative direction

answer: assuming rightward is positive, the velocity is positive whenever the car is moving to the right, and the velocity is negative whenever the car is moving to the left. the acceleration points in the same direction as the velocity if the car is speeding up, and in the opposite direction if the car is slowing down.

that's what i got you can count the number of atoms

> 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.