Answer:
The temperature must be changed to 4 times of the initial temperature so as to keep the pressure and the volume the same.
Explanation:
Pressure in the container is P and volume is V.
Temperature of the helium gas molecules =
Molecules helium gas = x
Moles of helium has = 
PV = nRT (Ideal gas equation)
...[1]
After removal of helium gas only a fourth of the gas molecules remains and pressure in the container and volume should remain same.
Molecules of helium left after removal = 
Moles of helium has left after removal = 
...[2]
The temperature must be changed to 4 times of the initial temperature so as to keep the pressure and the volume the same.
At the same temperature, steam burns are often more severe that water burns because of water's high HEAT OF VAPORIZATION.
Water possesses high heat of vaporization. The heat of vaporization refers to the amount of heat that is needed to convert a unit mass of water to gas. After getting to the boiling point, a lot of heat is still needed to be absorbed by a boiling water before it can be converted to the gaseous form. Thus, the heat that is inherent in the steam is greater than that which is found in the boiling water, that is why the steam causes more damages.
Nope, it's a physical change. When ice melts it changes into liquid water, it's still water. Changes in which no new substances are formed are physical changes, hence this is a physical change.
The half-life of the carbon-14 isotope is used in dating fossils in a process called radiocarbon dating.
hope this is adequate.
The answer is B. Decreasing the cylinder volume decreases the amount of space the gas has to occupy there for increasing pressure
