Yarns vary enormously in how far they go, so you need to look on the ball band where this information is often given. If not, the manufacturer's website may help.
Are you knitting or etc. because chrocheting takes up lots of yarn
The length of yarn in a skein varies greatly with brand, variety, etc. You can determine the length of the yarn by looking on the front of the label, where it is listed along with weight, recommended needle/hook size and dye lot
Another name for a hank of yarn would be a skein of yarn.
skein
To skein yarn without a niddy noddy, you can use a chair or your arm to wrap the yarn around in a loop, creating a skein.
Approximately 1000. However, brands vary. It should give the measurement on the ball band.
There is no hard and fast number that I could give you as an answer. It all depends on what the yarn is made of, what "weight" the yarn is (sock versus bulky, for example). So, as asked, this isn't really an answerable question--there is too much unknown about your yarn to answer with any certainty. My best suggestion would be to go to the yarn manufacturers website and look there for your answer. Or, go back to where you purchased the yarn, and ask there.
Yarn comes in different "gatherings"--ways that it can be sold. Your question mentioned 2 out of the three: ball of yarn and skein of yarn. The third would be a Hank of yarn. A hank is a skein of yarn (which is yarn in a large oblong shape, and tied in a few places around the skein to maintain a bit of control over the yarn staying in that loose shape), which has been twisted around itself to make for a smaller and more controllable yarn, which is easier to pack, and store. A hank also is a bit more manageable than a skein of yarn. A ball of yarn would be wound from a skein or a hank.
The yarn that is attached to the skein is often referred to as the "tail" or "end" of the skein. This tail is used to pull off the yarn for knitting or crocheting without unraveling the entire skein. In some cases, it may also be called the "working yarn" once it is being used in a project.
Depends on the yarn. There is yarn that is 100% cotton, but cotton/rayon mixes and other mixes are common.
A skein of wool can come in different weights. There is not a specific amount of wool needed in a skein.
You can not determine how many yards from the weight of the skein or cone. 50 grams is 1.75 ounces but it would depend on the exact thickness and type of yarn to know how many yards. The thicker the yarn the less the yards as a rule. Example a 50 gram ball of sport yarn can be anywhere from 110 to 170 yards give or take , but a 50 gram ball of bulky can be anywhere from 30 yards to 60 yards give or take ..