To introduce myself
Hello,every one!
My name is **** .
I'm a 15 years old boy.
I live in the beautiful city of Rizhao.
I'm an active ,lovely and clever boy.)
In the school , my favourite subject is maths .
Perhaps someone thinks it's difficult to study well .
But I like it.
I belive that if you try your best, everything can be done well.
I also like sports very much.
Such as,running,volleyball and so on.
I'm kind-hearted.
If you need help ,please come to me .
I hope we can be good friends!
OK.This is me .A sunny boy.(
追问请问把质量分数为5.3%的碳酸钠溶液蒸发掉60g水后,溶液变成了20mL,质量分数变为15.9%,则浓缩后中碳酸钠的物质的 量的浓度为多少呢?
追答这不应该是初一的吧...?
追问不好意思,那请问你是读几年级呢?
追答初三........