a given mass of gas occupies the volume of 500cm at 25c calculate the temperature in degree celcius at which it volume becomes doubled at constant pressure

How do you find a theoretical mass? is there a difference between theoretical mass and theoretical yield?

According to each substances heat of fusion, which of the items below requires more heat to be added per gram of substance to go from solid to liquid? silver sulfur water lead

Great amounts of electromagnetic energy from our sun and other bodies in space travel through space. which is a logical conclusion about these electromagnetic waves? their energy must be very their frequency must be very low these waves can travel without a medium they only travel through a vacuum of space