Question 9. imagine that a 2 g sample of cobalt, a lustrous grey metal, is heated until it melts. as it is heated, what will happen to the sample? a) its volume will decrease and its mass will stay the same. b) its mass and volume will increase. c) its volume will increase and its mass will decrease. d) its volume will increase but its mass will stay the same.

Select for each of the following statements whether it is correct or incorrect. (a) in an isothermal expansion of an ideal gas. (b) the temperature remains constant. (b) the pressure remains constant. (c) there is work done by the gas. (d) there is heat added to the gas. (e) the change in internal energy equals zero.

Ascientist wants to test ways to reduce pollution in lake . what is the bestway of doing this

A75-hp (shaft output) motor that has an efficiency of 91.0 percent is worn out and is to be replaced by a high-efficiency motor that has an efficiency of 95.4 percent. the motor operates 4368 hours a year at a load factor of 0.75. taking the cost of electricity to be $0.12/kwh, determine the amount of energy and money saved as a result of installing the high-efficiency motor instead of the standard motor. also, determine the simple payback period if the pu