Ammonia - PowerPoint PPT Presentation

1 / 15
About This Presentation
Title:

Ammonia

Description:

We can react nitrogen with hydrogen to produce a useful ... is exothermic. If the temperature is lowered the reaction will favour the exothermic reaction. ... – PowerPoint PPT presentation

Number of Views:3560
Avg rating:3.0/5.0
Slides: 16
Provided by: haybridge
Category:

less

Transcript and Presenter's Notes

Title: Ammonia


1
Ammonia
  • History, production, use

2
The Air
  • The air is made up of almost 78 nitrogen.
  • 21 oxygen.
  • We can react nitrogen with hydrogen to produce a
    useful substance called ammonia

3
Hydrogen
CH4(g) H2O(g) CO(g) 3H2(g)
  • Hydrogen is obtained via the cracking of methane.
  • Methane and steam are passed over a nickel
    catalyst at high temperatures.

4
Nitrogen
  • Nitrogen is very unreactive due to the strong
    triple covalent bond.
  • It is used to preserve food.
  • Liquid nitrogen is used to preserve human organs
    ready for operations.

5
Making Ammonia
  • Nitrogen and hydrogen react to form ammonia.
  • This requires high temperatures and pressures and
    an iron catalyst

6
Ammonia
  • Ammonia is a poisonous gas.
  • It has the formula NH3
  • Nitrogen is covalently bonded to three hydrogens.
  • It is used to make ammonium nitrate fertiliser.

7
Fritz Haber
  • Born 1868 in Prussia
  • Science Teacher
  • Self educated
  • Nobel Prize winner for his inventing a new way to
    manufacture ammonia from the nitrogen in the air.

8
The Haber Process (1908)
9
Conditions?
  • Unfortunately the reaction to produce ammonia is
    reversible.
  • Ammonia can break down to reform hydrogen and
    nitrogen.
  • Industry tries to stop this by altering the
    temperature and pressure.
  • You must know why they chose the relevant
    temperatures and pressures.

10
  • You can see from the chart that low temperatures
    and high pressures are best.

11
Pressure
  • High pressure is favoured.
  • There are less gasous products than reactants.
  • Forming products will lower the pressure.

12
  • High pressures favour making products
  • High pressures are expensive in industry
  • High pressures are dangerous.
  • A compromise pressure of 200 atmospheres is used.

13
Temperature
  • Lower temperatures are preferred.
  • The reaction producing ammonia is exothermic.
  • If the temperature is lowered the reaction will
    favour the exothermic reaction.
  • Hence producing products.

14
  • Low temperatures make more products
  • Low temperatures mean a slow reaction.
  • Industry compromises with a temperature of 450C.

15
You need to revise this!
Write a Comment
User Comments (0)
About PowerShow.com