in chinese,心急is a adjective,to describe sb's mood. 急着is a adverb. it usually followed by to do sth. for example: he was impatient =他很心急。 he is hurry to go=他急着走。

They are really similar.心急is more like adjective. 他迷路了所以很心急 -He gets lost ,so he is very 心急. And 急著is more used as verb. 他急著想找到正確的方向 -He 急著 to find the correct way

一、 '心急'(心急如焚，心急火燎) often acts as '谓语/predicate of grammar' and can be '定语/attributive' if adding a '的' after it. Sometimes, if you put a '地' after '心急', '心急地' can also be ‘状语/adverbial’. For example： 1) '我很(心)急，我还有好多作业没有写完'。 '别太心急，学习要一步一步来。' 中国的科研人员 *心急如焚*，苦苦思索着对策和出路。 '公司领导 *心急如焚*，公司职工如坐标针毡。' 2) 全部落的人们归心似箭，但 *心急 如焚的* 渥巴锡汗决定停止前进。 *心急 的* 农牧民计算了一下，“宁住帐篷，誓盖学堂”，纷纷自发集资，投工投料。 *心急 如焚的* 张德珍一口气读完儿子的信，愣了。 被历史耽误过的 *心急的* 父母几乎是直接用自己的愿望、理想塑造下一代人， 3) 白茹的心已经不平静了，她 *心急地* 希望剑波的思考松缓下来。 《林海雪原》 到了普律当丝家门口，她邀请我们上楼到她家里去参观她引以自豪的那些商品，让我们开开眼界。可想而知我是多么 *心急地* 接受了她的邀请。 《茶花女》 定好了弦，他 *心急地* 等着琴珠上场。两眼目不转睛地盯着上场门的帘子。《老舍》 The examples are from 'http://ccl.pku.edu.cn:8080/ccl_corpus/'（By 北京大学中国语言学研究中心）. 二、 '急着' often acts as '状语/adverbial'. It is often put before a verb or the predicate. For example： '你不用 *急着* 做出决定，选择职业不是一件小事'。 ‘任何事情都不要 *急着* 给出结论。’ 小王 *急着* 要出门去逛街。

.1心急can be used alone.but cannot used as 我心急做……you can say 我心好急，我心很急 for example :somebody ask you"你怎么了？"you can say心急。to express your nervous or anxious. 2.急着cannot be used alone.at least you should add 呢，急着呢。 usually,you can say急着呢/我急着呢/我急着做…… 急着，you can regard it as a adj

I am free. let me explain the 心急 and 急着 for you. 心急 it is 心 heart, mind, feeling and 急 hurry, rush , combine word as 心急。 it means your feeling is impatient and short-tempered, hurry. 我等这一天等得很心急。 I was impatient of waiting this day. 孩子很心急地去游乐场。The children went to playground in hurry. 急着 , when verb+着 it says you are doing something with something. 急着去看病。go to see doctor in hurry. 穿着红衣服。wear with red clothes. 看着书。read with books. it is common expression way. you can say 你心急着去看电视。you go to watch TV in hurry. I may not 100% correct, but I hope it is helpful.