Complete the equation for this reaction. $\text{FeCr}_2\text{O}_4 + 4\text{C} \rightarrow \text{Fe} + 2\text{Cr} + \text{[BLANK]}$
Suggest one disadvantage of obtaining chromium by reacting chromite with carbon.
Name the type of substance produced when a metal is mixed with other elements.
State the total of the oxidation numbers in the $\text{Cr}_2\text{O}_7^{2-}$ ion.
Determine the oxidation number of each Cr in $\text{Cr}_2\text{O}_7^{2-}$ ions. Show your working.
Calculate the volume of nitrogen gas produced at r.t.p., in $\text{cm}^3$, when 1.26 g of $(\text{NH}_4)_2\text{Cr}_2\text{O}_7$ is heated by following these steps: • Calculate the number of moles of $(\text{NH}_4)_2\text{Cr}_2\text{O}_7$ used. • Determine the number of moles of $\text{N}_2$ formed. • Calculate the volume of $\text{N}_2$ formed at r.t.p. in $\text{cm}^3$.