[susan53]

No. as long as means on the condition that. So for example, a mother might say to a teenage son or daughter :

You can go to the party as long as you're home by 11.30.

Other expressions you could use to repalace and include :
a) in addition to - which is a subordinating conjunction like as well as and used in the same way : .... emergency situations, in addition to offering you ...
b) the sentence adverbials Moreover, In addition, and Furthermore. These are slightly more formal and should either be used in a separate sentence - ...emergency situations. Moreover, they ofer you ... - or co-ordinated with and : They make communication faster and easier, help you in emergency situations, and in addition, offer you many different functions.

However, by far the best way to write your sentence would, in this case, be simply by using "and".

There are several advantages of mobile phones, such as making comunication faster and easier, helping you in emergency situations, and offering you many different functions to use.

In general, one subordinating conjunction (here you already have such as) is enough in a sentence. A good rule to follow when writing, in order to make your writing clear and understandable, is to aim for sentence of about 25-30 words with no more than one subordinate clause and one co-ordinated clause. Expert writers can include more than this, of course, and still remain clear. But if you have any doubts, it's a useful rule to follow.

Re : emergency situations - remember the answer to a previous question you asked, about specific and general situations. The is only used when you are referring to one or more specific things. When you are speaking generally, either use the plural or a/an + singular. So here you could say in an emergency situation or in emergency situations.