(1)由题知0.600g为生成CO2与H2O的总质量,根据质量守恒,也CH4与反应的O2的总质量.
设CH4的物质的量为xmol,由CH4+2O2=CO2+2H2O,可知反应氧气的物质的量为2xmol,则:
44x+36x=0.600
解得:x=0.0075
V(CH4)=0.0075mol×22.4L/mol=0.168L=168mL
反应消耗的氧气的体积为:168mL×2=336mL
碱石灰吸收后所剩余的体积为:840mL-168mL-336mL=336mL
故答案为:336mL;
(2)原混合气体中CH4与O2的体积比为:168mL:(840-168)mL=1:4,
故答案为:1:4.