Achemist isolated a gas in a glass bulb with a volume of 255 ml at a temperature of 25 and a pressure of 10 torr. the gas weighed 12.1 mg. what is the molecular mass of this gas

88.5 g/m is the molar mass for the gas

Explanation:

We need the Ideal Gases Law equation to solve this:

P . V = n . R . T

Pressure (P) = 10 Torr

We must convert to atm → 10 Torr / 760 Torr = 0.0131 atm

Volume (V) = 255 mL

We must convert to L → 255 mL /  1000 = 0.255 L

n = number of moles

moles = mass in g / molar mass

12.1 mg/ 1000 = 0.0121 g

T° = 25°C + 273K = 298K

R = 0.082 L.atm /mol.K

Let's replace the values

0.0131 atm . 0.255L = 0.0121 g / x .  0.082 L.atm /mol.K  . 298K

(0.0131 atm . 0.255L) / (0.082 L.atm /mol.K  . 298K) = 0.0121 g / x

1.367×10⁻⁴ /mol = 0.0121 g / x

x = 0.0121 g / 1.367×10⁻⁴ mol = 88.5 g/m

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.