First question. Applying ideal gas equation PV=nRT, P= 101.3 x 10³Pa = 1atm. therefore, 1 x 260 x 10^-3 = n x 0.082 x 294.( Temperature in kelvin=273+21). n = 0.01 moles. Volume of gas at STP= n x 22.4 = 0.01x22.4 = 0.224L. Hope this helps
Lithium, Chlorine, and Oxygen
hope this helped :)
I think c may be your anwser but im not too sure :/ srry if u get it wrong!
A garduated cylander, in order to find the amount of water displaced you see how much the water has risen