An unknown gas with a formula of HX is contained in a 25.0 L tank at 1.2 atm and 25.0 oC. What is the chemical formula of the gas if the mass of the gas is 44.7 g?

HCl

Explanation:

Volume = 25L

Temperature = 25.0 oC + 273 = 298 K (Converting to kelvin units)

Pressure = 1.2 atm

Mass of gas = 44.7g

Formular of gas = HX

To solve this, we have to know the identity of X. One qay to do that is by obtaining the molecular mass of the compound.

To get the molar mass, we need the number of mole.

Using the ideal gas equation;

PV = nRT

where R = gas constant = 0.082 057 L atm K−1  mol−1

n = PV / RT

n = 1.2 * 25  / 0.082 057 * 298

n = 30  /  24.45

n = 1.227 mol

The relationship between number of moles and molar mass is given as;

Nummber f moles = mass  / molar mass

Molar mass = mass  / Number of moles

Molar mass = 44.7 / 1.227

Molar mass =  36.43 g/mol

Molar mass of gas X = Molar mass of H + Molar mass of X

36.43 = 1 + X

X = 36.43 - 1 = 35.43

Chlorine is the only element with molar mass approximate to 35.43

Hence X = Cl

The chemical formular = HCl

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.