100 grams Helium Gas are in a sealed container at STP. How many grams are there?

100 grams,

Explanation:

Note: I assume you want to find the volume of the gas, since the mass (100 grams) is already given.

First of all, we have to find the number of moles of the gas. This is given by:

where

m = 100 g is the mass of the gas

is the molar mass of helium

Substituting,

Now we have to find the volume of the gas. We can do it by using the equation of state for an ideal gas:

where

is the pressure of the gas at STP

V is the volume of the gas

n = 25 mol is the number of moles

is the gas constant

is the temperature at STP

Solving for V, we find the volume:

the law of conservation of mass states that in a chemical reaction, the total mass of reactants is equal to the total mass of products. because atoms are only rearranged in a chemical reaction, there must be the same number of sodium atoms and chlorine atoms in both the reactants and products

the formula mass of a molecule or a compound is the sum of the atomic weights of the atoms in its empirical formula

(that's what i know about formula mass)