4 NH3+ 7O2 --> 4NO2+6H2O How many grams of O2 are needed to produce 1.26 x 1028 molecules of H2O?
no idea how to do this, really need to get it done :(

What are the first three quantum numbers for the electrons located in subshell 2s?

The yearly amounts of carbon emissions from cars in belgium are normally distributed with a mean of 13.9 gigagrams per year and a standard deviation of 5.8 gigagrams per year. find the probability that the amount of carbon emissions from cars in belgium for a randomly selected year are between 11.5 gigagrams and 14.0 gigagrams per year. a. 0.340 b. 0.660 c. 0.167 d. 0.397

Asample of tin (ii) chloride has a mass of 0.49 g. after heating, it has a mass of 0.41 g.  what is the percent by mass of water in the hydrate?   %