Question

Calculate the wt% c of an alloy that contains 5 g carbon and 100 g fe. express your answer to the nearest 0.1 %. 4.80 submitmy answersgive up correct part b - atomic % for the same amount of fe and c, what is the atomic % of c concentration? express your answer to the nearest 0.1 %.

Answer 1

a. Mass % = 4.8 %; b. Atom % = 18.9 %

Part a. Mass percent

Mass % = mass of component/total mass × 100 %

Total mass = mass of C + mass of Fe = 5 g + 100 g = 105 g

∴ Mass % = mass of C/total mass = 5 g/105 g × 100 % = 4.8 %

Part b. Atom percent

Atom % = atoms of component/total atoms × 100 %

Step 1. Calculate the atoms of C

Atoms of C = 5 g C × (1 mol C/12.01 g C) × (6.022 × 10^23 atoms C/1 mol C)

= 2.5 × 10^23 atoms C

Step 2. Calculate the atoms of Fe

Atoms of Fe

= 100 g Fe × (1 mol Fe/55.845 g Fe) × (6.022 × 10^23 atoms Fe/1 mol Fe)

= 1.08 × 10^24 atoms Fe

Step 3. Calculate the total atoms

Total atoms = atoms of C + atoms of Fe

= 2.5 × 10^23 atoms + 1.08 × 10^24 atoms = 1.33 × 10^24 atoms

Step 4. Calculate the atom percent

∴ Atom % = atoms of C/total atoms

= 2.5 × 10^23 atoms/1.33 × 10^24 atoms × 100 % = 18.9 %