How many resonance structures does NH3 have?

I believe that there are none, but I would like some confirmation ...

The speed of a transverse wave in a string is 12 meters per second. If the frequency of the source producing this wave is 3 hertz what is it's wavelength

A series of lines involving a common level in the spectrum of atomic hydrogen lies at 656.46 nm, 486.27 nm, 434.17 nm, and 410.29 nm.

The number of protons in an atom is called the what?

Complete and balance the equation for the double replacement reaction LiOH (aq) + Fe (NO3) 3 (aq)

When heat energy is added two changes are observed: Change A: solid changes phases to a liquid Change B: liquid changes phases to a gas What are the names or phase changes in A and B

1. What is something you might see a scientist doing?

Is fire living or non living

Which of these is used to find the estimated age range of a fossil?

I want to convert atoms to moles. My friend tells my to multiply the number of atoms by 6.02 x 102. Is my friend correct?

Combining 0.301 mol Fe2O3 with excess carbon produced 11.6 g Fe. Fe2O3+3C⟶2Fe+3CO What is the actual yield of iron in moles?