BIt speeds up the reaction.[1]
A catalyst speeds up the reaction but does not change the yield, and it is not used up. The backward reaction still happens.
Aincreasing the pressure[1]
A higher pressure gives a higher yield. A higher temperature lowers the yield, a catalyst does not change the yield, and the cooler is needed to remove the ammonia.
N2(g) + 3H2(g) ⇌ 2NH3(g) [1]
The cracking of crude oil fractions. [1]
So that they are not wasted: they pass over the catalyst again to make more ammonia. [1]
A reaction that can go both forward and backward. [1]
Cburning charcoal[1]
The ash cannot be turned back into charcoal. The other three can go both forward and backward.
NH4Cl(s) ⇌ NH3(g) + HCl(g) [1]
Ammonia has a lower relative molecular mass (17) than hydrogen chloride (36.5) [1]
so ammonia diffuses faster and reaches the litmus paper first. [1]
Ammonium chloride: ammonia and hydrogen chloride combine again where the tube is cooler (both points for the mark). [1]
Acracking of oil fractions[1]
Hydrogen comes from cracking crude oil fractions. Fractional distillation of liquid air is the source of nitrogen.
BHydrogen is obtained from fractional distillation of liquid air.[1]
Nitrogen, not hydrogen, is obtained from liquid air. Hydrogen comes from cracking crude oil fractions.
CIron is used to increase the yield of ammonia.[1]
Iron is a catalyst. It speeds up the reaction but does not change the yield.
Aincrease the pressure to 450 atm[1]
A higher pressure increases the yield. A higher temperature lowers the yield, the gases react in a 1 : 3 ratio, and a catalyst does not change the yield.
BAt 250 °C, the rate of ammonia production is too low.[1]
450 °C is a compromise. At 250 °C the yield is higher, but the reaction is far too slow.
CHigh pressure is used to increase the rate and yield of the reaction.[1]
High pressure gives both a faster rate and a higher yield. Only nitrogen comes from liquid air, iron does not change the yield, and a high temperature lowers the yield.
N2 + 3H2 ⇌ 2NH3: correct balanced equation [1]
Reversible arrow ⇌ [1]
Nitrogen from the fractional distillation of liquid air or hydrogen from the cracking of crude oil fractions. [1]
A reaction that can go both forward and backward at the same time. [1]
A pressure of 250 atm and a temperature of 450 °C. [1]
450 °C, 250 atm and a finely divided iron catalyst. [1]
The reaction between nitrogen and hydrogen is reversible. [1]