5. 54 J of heat is required to raise the temperature of a 2.47g unknown substance from 17.10C to 46.70C. a) Calculate the specific heat of the substance b) What is the substance?

Can you guys me with question no. 5!

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

Calculate the number of kilojoules to warm 125 g of iron from 23.5°c to 78.0°c.