Why are the N-O bond lengths in NO− 3 the same? 1. The dot structure for this ion shows that all three bonds are single bonds. 2. The longer bond length is always used. 3. The shorter bond length is always used. 4. Resonance

Resonance

Explanation:

Resonance is an idea in chemistry that is used to explain such properties as equal bond lengths, bond angles and some other chemical behaviours. Resonance structures show the possible distribution of electrons in molecules. All the contributing canonical or resonance structures give a clue regarding the true structure of the chemical specie under consideration.

The true structure of the specie is somewhere in between that of all the contributing canonical structures. Resonance is often employed to explain properties such as equal bond lengths and bond angles just as typified in the question under consideration.

1. 1 mole of anything contains 6.022x10^23 pieces  

d  

2. a  

3. c, number  

5. 1.24x10^24atoms / 6.022x10^23atoms/mole = 2moles h2 atoms  

6. fe2br3 mass = 2moles x mass fe + 3 moles x mass br  

molar mass = grams / number of moles = g/mole  

to find moles = g / molar mass  

to find mass = g = molar mass / moles

i believe the answer is a.