A balloon has a volume of $404{\mathrm{m}}^3$ and is filled with helium of mass $70.0\mathrm{kg}$. The temperature inside the balloon is $17.0°\mathrm{C}$. Determine the pressure inside the balloon.

A flask has a volume of $5.0\times {10}^{-4} {\mathrm{m}}^3$ and contains air at a temperature of $300 \mathrm{K}$ and a pressure of $150 \mathrm{kPa}$.

(a) Calculate the number of moles of air in the flask.

A flask has a volume of $5.0\times {10}^{-4} {\mathrm{m}}^3$ and contains air at a temperature of $300 \mathrm{K}$ and a pressure of $150 \mathrm{kPa}$.

(b) Determine the number of molecules in the flask.

A flask has a volume of $5.0\times {10}^{-4} {\mathrm{m}}^3$ and contains air at a temperature of $300 \mathrm{K}$ and a pressure of $150 \mathrm{kPa}$.

(c) Estimate the mass of air in the flask. You may take the molar mass of air to be $29 \mathrm{g} /\mathrm{mol}$.

The molar mass of helium is $4.00 \mathrm{g}/\mathrm{mol}$.

a. Calculate the volume of $1.0 \mathrm{mol}$ of helium at standard temperature and pressure (STP) i.e., at $T=273\mathrm{K}, P=1.0\times {10}^5 \mathrm{Pa}$  

The molar mass of helium is $4.00 \mathrm{g}/\mathrm{mol}$. Calculate the volume of $1.0 \mathrm{mol}$ of helium at standard temperature and pressure (STP) i.e., at $T=273\mathrm{K}, P=1.0\times {10}^5 \mathrm{Pa}$  

b. Determine the density of helium at STP.

The molar mass of the helium is $4.0 \mathrm{g}/\mathrm{mol}$. Calculate the volume of $1.0 \mathrm{mol}$ of helium at standard temperature and pressure (STP) i.e., at $T=273\mathrm{K}, P=1.0\times {10}^5 \mathrm{Pa}$  

c. Estimate the density of oxygen gas at STP ( molar mass of oxygen gas is $32 \mathrm{g}/\mathrm{mol}$)