0.0278, how many significant figures

What is the number of moles of chemical units represented by 9.03x10^24? and how do i show work? (dumb it down )

Astudent completes a titration by adding 12.0 milliliters of naoh(aq) of unknown concentration to 16.0 milliliters of 0.15 m hcl(aq). what is the molar concentration of the naoh(aq)? 1)5.0 m 2)0.20 m 3)0.11 m 4)1.1 m

Acandle’s wick is the fabric string that holds the flame, and it burns down at a constant slow pace when the candle is lit. the wick is usually surrounded by wax. which is the most important property of covalent compounds that makes them useful for making candle wax? a low boiling point a low melting point a high boiling point a high melting point