Question

?量分数.（2）若200mL反应后所得溶液的体积为,求所得溶液中溶质的物质的量浓度.

Answer 1

2Na2O2+2H2O==4NaOH+O2↑

n(O2)=1.12/2.4=0.05mol

n(Na2O2)=2*0.05=0.1mol

m(Na2O2)=78*0.1=7.8g

Na2O质量分数=(14-7.8)/14=44.3%

n(Na2O)=(14-7.8)/62=0.1mol

n(NaOH)=2*0.1+2*0.1=0.4mol

c=0.4/0.2=2mol/L