A 8.0 L sample at 25•C and 1.00 atm of pressure contains 0.5 moles of gas. If an additional 0.75 moles of gas at the same pressure and temperature are added, what is the final total volume of the gas?

The final total volume of the gas is 20 L

Explanation:

According to the Avogadro's law, the volume of gas is directly proportional to the number of moles of gas at same pressure and temperature. That means

or,

where,

= initial volume of gas = 8.0 L

= final volume of gas = ?

= initial moles of gas = 0.5 moles

= final moles of gas = 0.5 + 0.75 = 1.25 moles

Putting in the values , we get:

The final total volume of the gas is 20 L

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e