Which phrase describes a solution?

A. a homogeneous mixture

B. a graduated substance

C. a heterogeneous mixture

D. a primary mixture of elements

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

What’s the scientific notation for the number 6,840,000,000

How many moles of air are there in a human lung with a volume of 2.4 l at stp? explain your answer