How many grams of fluorine are required to produce 10.0 g of xef6?

Asingle atom of an element has 21 neutrons, 20 electrons, and 20 protons. which element is it? ok o z

0.09 moles of sodium sulfate in 12 ml of solution

Mike and mitchell decide to have a foot race. they mark off a stretch of 100 yards, and recruit cindy to work the stopwatch. after running the race and looking at the results, cindy declared that mitchell was the fastest. so how did the boys times compare?