Hey there!
The molar mass of nitrogen is 14.007.
Convert grams to moles:
21.2 ÷ 14.007 = 1.51
The sample containing 21.2g of nitrogen contains 1.51 moles of nitrogen.
Hope this helps!
You should read up on Proust's law, better known as the Law of Definite Proportions. This is a chemical law that defines your question more generally, on why the ratio of elements and ions are always fixed.
Basically, this compound Magnesium(II) Chloride is MgCl2 because it has the same number of protons, neutrons, and electrons all the way. This defines the properties of the compound or atom.
Answer: 1.25 miles per minute
Explanation:
Average speed is the rate of change of total distance covered per unit time.
i.e Average speed = (Total distance / Time taken)
Total distance covered = (25miles + 40 miles + 70 miles + 15 miles)
= 150 miles
Total time taken = ( 15 minutes + 30 minutes + 1 hour + 15 minutes) = 120 minutes
Since 60 minutes = 1 hour, the total time taken is 120 minutes
Now, apply Average speed = (Total distance / Time taken)
= (150 miles / 120 minutes)
= 1.25 miles per minutes
Thus, Joseph drove with an average speed of 1.25 miles per minute.