## 4D.23

VioletKo3F
Posts: 103
Joined: Sat Sep 07, 2019 12:18 am

### 4D.23

Why do you need to subtract twice the enthalpy of formation of NO to get the total reaction enthalpy?

Angela Patel 2J
Posts: 110
Joined: Sat Aug 24, 2019 12:17 am

### Re: 4D.23

Because there are two moles of NO gas. Standard enthalpies of formation are given per mole, so you need to multiply each one by the number of moles when using the equation given on the formula sheet.