A:n1<n2,a为红光,b为紫光
B:n1<n2,a为紫光,b为红光
C:n1>n2,a为红光,b为紫光
D:n1>n2,a为紫光,b为红光
3H2(g)+Fe2O3(s)=2Fe(s)+3H2O(g)△H2
2Fe(s)+ 32 O2(g)=Fe2O3(s)△H3
2Al(s)+ 32 O2(g)=Al2O3(s)△H4
2Al(s)+Fe2O3(s)=A12O3(s)+2Fe(s)△H5
下列关于上述反应焓变的判断正确的是( )
下列成语使用有错误的一项是( )。
2017年我国实施的一系列新政将影响百姓的生活,如启动医保跨省就医结算;医保卡基本实现全国一卡通……这些新政确立的总依据是( )
∫022x-exdx=____
This is a photo of my family . I'm John . I'm ten . My sister is seven . We are in the same school .My grandparents are Americans . My father is 42 .He is a driver . My mother is 40 . She is a teacher . We are very happy .