Question

Chromium metal can be produced by the following reaction:

3Si + 2Cr2O3 - 4Cr + 3SiO2
In an experiment where there is an excess of cr2o3, what mass (in grams) of cr can be produced from 0.250 moles of si?

Answer 1

17.3 g Cr

Step-by-step explanation:

To find the mass of chromium, you need to (1) convert moles Si to moles Cr (using the mole-to-mole ratio from equation coefficients) and then (2) convert moles Cr to grams Cr (using the atomic mass). It is important to arrange the conversions in a way that allows for the cancellation of units. The final answer should have 3 sig figs to match the sig figs of the given value (0.250).

3 Si + 2 Cr₂O₃ ---> 4 Cr + 3 SiO₂
^ ^

Atomic Mass (Cr): 51.996 g/mol

0.250 moles Si 4 moles Cr 51.996 g
------------------------- x -------------------- x ------------------- = 17.3 g Cr
3 moles Si 1 mole