1. Tardigrade
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  3. Chemistry
  4. 2.5 g of protein containing only glycine ( C 2 H 5 NO 2) is dissolved in water to make 500 mL of solution. The osmotic pressure of this solution at 300 K is found to be 5.03 × 10-3 bar. The total number of glycine units present in the protein is (Given: R =0.083 L bar K -1 mol -1 )

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Q. $2.5 g$ of protein containing only glycine $\left( C _{2} H _{5} NO _{2}\right)$ is dissolved in water to make $500 mL$ of solution. The osmotic pressure of this solution at $300 K$ is found to be $5.03 \times 10^{-3}$ bar. The total number of glycine units present in the protein is ___ (Given : $R =0.083 \,L$ bar $K ^{-1} \,mol ^{-1}$ )

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Solution:

$\pi= CRT$
$5.03 \times 10^{-3}= C \times 0.083 \times 300$
$C =0.202 \times 10^{-3} M$
Moles of protein $=0.202 \times 10^{-3} \times 0.5$
$=10^{-4} \times 1.01$
$1.01 \times 10^{-4} \times \frac{2.5}{ M }$
M(molar mass of protein $)=24752$
$\therefore$ No. of glycine units $=\frac{24752}{75}=330.03$