CFCs and their associated compounds were developed in the early 1900s as a non-toxic, non-flammable solution to other more dangerous products such as ammonia.
Answer: D) 1.00 g
Explanation:
According to the Avogadro's law, the volume of gas is directly proportional to the number of moles of gas at same pressure and temperature. That means,

or,

where,
= initial volume of gas = 2.00 L
= final volume of gas = 3.00 L
= initial moles of gas =
= final moles of gas = ?
Now we put all the given values in this formula, we get


Mass of helium =
Thus mass of helium added = (3.00-2.00) g = 1.00 g
Noice but I don’t get why was this necessary
Answer:
Ability to conduct electricity
Melting point