What is the percent by mass of Fluorine in Nitrogen triflouride NF3?

The answer to your question is 80.3%

Explanation:

Data

Percent by mass of F

molecules NF₃

Process

1.- Calculate the molar mass of nitrogen trifluoride

molar mass = (1 x 14) + (19 x 3)

                    = 14 + 57

                    = 71 g

2.- Use proportions and cross multiplications to find the percent by mass of F. The molar mass of NF₃ is equal to 100%.

                       71 g of NF₃ 100%

                       57 g of F   x

                            x = (57 x 100)/71

                            x = 5700 / 71

                            x = 80.3%

3.- Conclusion

Fluorine is 80.3% by mass of the molecule NF₃