It can be. The 5w20 is the weight of the oil which you can buy conventional or synthetic. If it is synthetic it will say so right on the container. If it does not say synthetic it is conventional oil.
Yes, you can even mix synthetic with conventional oil.
It is a combination of synthetic oil and conventional oil.
It is conventional oil and contains no synthetic oil. 3000 & 5000 are part synthetic and part conventional. 7000 is a full synthetic oil.
That's easy synthetic oil. Ill tell you why it sounds better
I will change my oil from conventional oil to synthetic oil on my next oil change.
Semi synthetic or synthetic blend is a combination of synthetic and conventional oil. Full synthetic oil is just that 100% synthetic oil.
You can use synthetic, synthetic blend, or conventional oil. It is your choice.
Synthetic and conventional oil can be mixed and used with no problem. That is exactly what a synthetic blend that you can buy is. A mix of synthetic oil and conventional.
It they are the same weight oil as in SAE 30 weight oil there is no difference and they are identical. 30 weight oil is 30 weight oil synthetic or conventional.
Yes, semi synthetic is a blend of synthetic and conventional oil already.
Yes, without any issues. That's what synthetic blend oils are (better than conventional oil, not quite as good as pure synthetic).