A synthetic chemist designs a spherical catalyst nanoparticle for use in green hydrogen production. The nanoparticle has a surface area of 1.8 × 10-7 mm2 and a volume of 4.5 × 10-11 mm3.
What is the surface area to volume ratio of this nanoparticle?
400:1400 : 1400:1
4000:14000 : 14000:1
0.00025:10.00025 : 10.00025:1
40:140 : 140:1