V_1->"volume of hydrogen in cylinder"=2.82L
T_1->"Temperature of hydrogen in cylinder"
=27^@C=27+273=300K
P_1->"Pressure of hydrogen in cylinder"=20atm
At NTP
P_2->"Pressure"=1atm
T_2->"Temperarture"=273K
V_2->"Volume"=?
By gas law
(P_2V_2)/T_2=(P_1V_1)/T_1
=>V_2=(P_1V_1T_2)/(P_2T_1)
=(20xx2.82xx273)/(1xx300)=51.324L
Excluding the minlmum remaining 2.82L gas in the cylinder at NTP maximum (51.324-2.82)L=48.504L gas can be used for filling baloons.
Volume of each spherical baloon of diameter 7cm is
=4/3pi(7/2)^3cm^3=4/3*22/7*7^3/8cm^3
=0.1796L
Hence the maximum number of baloons that can be filled with hydrogen from the cylinder is
="Total volume of gas"/"volume of a baloon"
=48.504/0.1796~~270" "(rounding to nearest whole number)
