[debb1232003]

Ca(s) + CO2(g) -----> CaCO3(s)
What mass of CO2 could be absorbed by 1.25g of CaO?

What volume would this CO2 occupy at STP?

[Unknown008]

(Note that in your equation, you typed Ca instead of CaO)

Find the relative mass of CaO.
Thus, find the number of moles of CaO present in 1.25 g of CaO.
Using your equation, deduce the number of moles of CO2 required.
At stp, 1 mole of gas occupies 22.4 L or 22.4 dm^3. You have the numberof moles of CO2, find the volume!