For decades, all Apple's portable computers (and Mac Minis too) have been 100-240 V - making them perfect for travel. So yes you can.
Power cords in Argentina look a bit different from those in US (
this?) so an adapter won't hurt. The good news is you don't need a voltage converter, so any US type > Argentine type will do, though something
like this would generally be best IMHO. I had years of pain with three types of plugs in use constantly - US and European plugs in UK type input, then those US input in EU input and all constantly crossed over. End result - about six of that type of adapters (sometimes they sell them at airports and planes too), each costing more than just normal one way adapters, but they work everywhere so wherever I travel I don't need to buy any more adapters. And that many adapters as I didn't bother to get local power cords...
Anyway, to a longer term solution: if you would stay there much longer, you could always get a nomal local Apple power cord and use that for the last piece of the cable. That separate part you could always buy from an Apple reseller or repair center, but for one week of travel it would be quite an overkill. (And especially as there are those of us who didn't bother to get a local cable for over 5 years of different laptops...)
Buen viaje - Buenos Aires should be awesome. Enjoy