#2) Perform the following calculations and report the answer to the correct number of significant figures with the proper units!

52 g/(75.2 mL – 34.90 mL) = !
1.42 cm + 5.903 cm - 3.0 cm =
12.50 cm x 0.23 cm x 1 cm =
2.34 x 10-3 m x 5.0 x 105 m =
1500 m/2.745 s=
1200 mL + 235 mL + 2.030 mL

Ineed to find the answer of this question because i dont understand it

The content of manganese (mn) in steel was determined spectrophotometrically and with the use of the standard addition method. an unknown sample of mn from a digested steel sample gave an absorbance of 0.185 when analyzed spectrophotometrically. when 5.00 ml of solution containing 95.5 ppm mn was added to 50.0 ml of the unknown steel solution (digested sample), the absorbance was 0.248. calculate the concentration, in parts-per-million (ppm), of mn in the digested steel sample solution.

What volume does 1.70 ×10–3 mol of chlorine gas occupy if its temperature is 20.2 °c and its pressure is 795 mm hg?