A:2H2+O2 →点燃 2H2O
B:H2+Cl2 →点燃 2HCl
C:2CO+O2 →点燃 2CO2
D:CH4+2O2 →点燃 2H2O+CO2
下列属于物质物理性质的是( )
①A试管中产生的气体是____,B试管中产生的气体是____,由此证明电解水时发生了____变化,该变化的文字表达式为____,基本反应类型是____.
②已知化学变化前后元素种类不变,那么由此实验可得出水是由____组成的.
CH4、X、H2O、HF四种化合物是按它们的相对分子质量和化合价而有规律地排列的,其中X应该是( )
听短文完成表格。
My friend Cindy
Where does Cindy live?
She lives____.
What is Cindy fike?
She is____.
What does Cindy do on weekends?
She____with her mother.
What's Cindy good at?
She is good at____.
What does Cindy do after school?
She always____with me.