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The value of heat of formation of SiO(2)...

The value of heat of formation of `SiO_(2)` and MgO are 48.24 and 34.7 kJ respectively. The heat of reaction :
`2Mg + SiO_(2) rarr 2MgO + Si` is :

A

21.16 kJ

B

`-21.16 kJ`

C

13.62 kJ

D

`-13.62 kJ`

Text Solution

Verified by Experts

The correct Answer is:
A
`Delta H = 2 Delta H_(f) (MgO) + Delta H_(f) (Si) - 2 Delta H_(f) (Mg) - Delta H_(f) (SiO_(2))`
`= 2 xx 34.7 + 0 - 2 xx 0 - 48.24`
= 21.16
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