How many electrons must be added to an object to give it an overall net charge of -3.0 x 10^-7 c? the charge of an electron is -1.602 x 10^-19 c.
1.9 x 10^12 electrons
3.1 x 10^13 electrons
2.0 x 10^10 electrons
1.4 x 10^14 electrons

Which of the following is considered to be a vector?               a.  temperature    b.  velocity    c.  time    d.  mass

2kg of refrigerant 134a undergoes a polytropic process in a piston-cylinder assembly from an initial state of saturated vapor at 2 bar to a final state of 12 bar, 80 degree c. a)determine the work for the process in kj. b)sketch the process on a p-v diagram.

Which type of reaction is shown in this energy diagram? energy products activation energy reactants time o a. endothermic, because energy is released to the surroundings o b. exothermic, because energy is absorbed from the surroundings o c. exothermic, because energy is released to the surroundings o d. endothermic, because energy is absorbed from the surroundings