Question

Calculate no of moles of Hydrogen gas contained in 20 L flask at 270C exerting pressure 70 cm Hg. Given R = 0.082 L atm K – mol–​

Answer 1

$\huge \: \red \star \: { \large \pink { \underline\mathcal{ANSWER}} } \: \red\star \: </p><p>$

we know gas at high temperature and very low pressure behaves ideally

so,

PV = nRT

where

p is pressure

v is volume

n no of moles

R gas constant

T temperature

here

p = 70 cm Hg = 70/760 atm

V = 20L

T = 270+273= 543

n = ?

R = 0.082 L atm per K mol

note :- for calculationmake simple 1/12 also can be taken instead of 0.082

$\rightarrow \: \frac{70}{760} \times 20 = n \: \times 0.082 \times 543 \\ \\ \rightarrow1.84 = n \times 44.526 \\ \\ \rightarrow \: n = \frac{1.84}{44.526} = \boxed{\red{0.041 \: \: \: mole}}$

hope it helps

Answer 2

ANSWER

⋆

we know gas at high temperature and very low pressure behaves ideally

so,

PV = nRT

where

p is pressure

v is volume

n no of moles

R gas constant

T temperature

here

p = 70 cm Hg = 70/760 atm

V = 20L

T = 270+273= 543

n = ?

R = 0.082 L atm per K mol

note :- for calculationmake simple 1/12 also can be taken instead of 0.082

→

760

70

×20=n×0.082×543

→1.84=n×44.526

→n=

44.526

1.84

=

0.041mole

Hope it helps you :)