Can a physical change, change what a substance is?

List and describe the neurological effects of the vocs and other air pollutants,as described by dr.theo colborn

A20 liter cylinder of helium at a pressure of 150 atm and a temperature of 27°c is used to fill a balloon at 1.00 atm and 37°c. what is the volume of the balloon? a. 0.14 liters b. 3000 liters c. 2900 liters d. 2400 liters e. 3100 liters

The vapor pressure of water at 25.0°c is 23.8 torr. determine the mass of glucose (molar mass = 180 g/mol) needed to add to 500.0 g of water to change the vapor pressure to 22.8 torr.