Check If File Exist In C Code Example
Example: c check if file exists
if( access( fname, F_OK ) == 0 ) { // file exists } else { // file doesn't exist }Chemistry - Bond Angles In NH3 And NCl3
Answer : Solution 1: As Tan Yong Boon stated, it is Bent’s Rule with which we can explain the lower bond angle of \ce N F 3 \ce{NF3} \ce NF 3 when compared to \ce N H 3 \ce{NH3} \ce N H 3 . The rule as stated by Henry Bent: Atomic s character concentrates in orbitals directed towards electropositive substituents. Fluorine is more electronegative that hydrogen, and the \ce N − F \ce{N−F} \ce N − F bond would have greater p character than the \ce N − H \ce{N−H} \ce N − H bond. And more s character leads to large bond angles. Thus, the bond angle is greater in \ce N H 3 \ce{NH3} \ce N H 3 than in \ce N F 3 \ce{NF3} \ce NF 3 . Now, consider \ce N C l 3 \ce{NCl3} \ce NCl 3 . Clearly, \ce C l \ce{Cl} \ce Cl atom islarger in size than the central atom, nitrogen. Hence the higher bond angle here is due to the steric crowding caused by \ce C l \ce{Cl} \ce Cl atoms.(More pronounced than the electrongativity of \ce C l \ce{Cl} \ce Cl atom). They repel eachother and hence b...
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