Aknown number of moles of gas is placed in a
flexible container. what will happen if some of
the gas is removed from the container while the
pressure and temperature are kept constant?
a. the volume will increase.
b. the volume will decrease.
c. the volume will stay the same.

A. The volume will increase.

Explanation:

As per Avagadro’s law  

At constant temperature and pressure, the volume occupied by a gas is directly proportional to the number of moles of the gas.

Directly proportional means when one increases the other one too will increase. That is, Equal volume of different gases will have the same number of moles at constant temperature and pressure.  

1 mole of Hydrogen gas at T = 273K and P = 1 atm occupies a volume of 22.4L

1 mole of Argon gas at T = 273K and P = 1 atm occupies a volume of 22.4L

This is given by the expression  

(at constant temperature and pressure)

Introducing a constant we have  

Where V is the volume, n is the number of moles and k represents a constant.

When there is a change in volume or number of moles we make use of the expression  

As volume increases the number of moles occupies too will increase.

there are two significant figures.

it has both hydrogen and oxygen