Where is the 4 coming from?

How many moles are equivalent to 55.5g of nano3

Which of these best describes an ionic bond?

Why does the sun appear to be the brightest star in the sky? a- its apparent brightness is much greater than other stars. b- it burns more gas, making it brighter than any other star. c- it is the largest star in the galaxy, so it is the brightest star. d- its relative distance to earth is closer than the other stars.