Question

How much heat is given off when $8g$ of hydrogen reacts in: $2H_2+O_2\to 2H_{2}O;△H=-115.60kcal$

• A. $-57.8kcal$
• B. $-115.6kcal$
• C. $-173.4kcal$
• D. $-231.2kcal$
• E. $-462.4kcal$

Answer 1

The correct option is D $-231.2kcal$

No. of moles in $8g$ of hydrogen $=$$8/2$$=$$4mole$

heat released when $2mole$ of $H_2$ reacts$=$$-115.6cal$

hence heat released when $4mole$ of $H_2$ reacts$=$$-115.6\times 2cal$$=$$-231.2kcal$