HELP PLEASE What is the mass of 2.15 liters of N2 gas at STP? (5 points)
1) 1.82 grams
2) 2.68 grams
3) 2.92 grams
4) 3.11 grams

What is the composition, in atom percent, of an alloy that consists of 4.5 wt% pb and 95.5 wt% sn? the atomic weights for pb and sn are 207.19 g/mol and 118.71 g/mol, respectively.(a) 2.6 at% pb and 97.4 at% sn(b) 7.6 at% pb and 92.4 at% sn(c)97.4 at% pb and 2.6 at% sn(d) 92.4 at% pb and 7.6 at% sn

Which position represents spring in the southern hemisphere? a) b) c) d)

Stage in which a star’s outer layers have started to cool and grow outward?