When the temperature of a rigid hollow sphere containing 685 l of helium gas is held at 621 k, the pressure of the gas is 1.89 x 10^3 kpa. how many moles of the helium does the sphere contain? explain how you got the answer.

Which statement describes evidence of a chemical reaction? a) ice melting eliminate b) water boiling c) lighting a match d) grape juice freezing

At room temperature what happens to the average kinetic energy of the molecules of a solid, liquid, and a gas

The table compares the number of electrons in two unknown neutral atoms. comparison of electrons atom number of electrons a 10 d 11 use this information to determine the number of valence electrons in the atoms. which of the following correctly compares the stability of the two atoms? both are unreactive. both are highly reactive. a is unreactive and d is reactive. a is reactive and d is unreactive.