Starter quiz
- Which of the following statements about bases are correct?
- Bases have a pH less than 7.
- All bases are soluble in water.
- A strong base has a pH of 14. ✓
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- Nitrogen can be found in Group 5, period 2 of the periodic table. What does this tell you about the electron configuration in nitrogen?
- Each atom has 2 shells of electrons. ✓
- Each atom has 5 shells of electrons.
- Each atom's outer shell contains 5 electrons. ✓
- Each atom's outer shell contains 2 electrons.
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- What term do we use in science to show that a substance is dissolved in water?
- 'aqueous' ✓
- Ammonium chloride has the formula NH₄Cl. Which of the following statements about the formula for ammonium chloride are correct?
- The ratio of hydrogen to chlorine is 4 : 1. ✓
- The ratio of nitrogen to chlorine is 1 : 1. ✓
- The ratio of hydrogen to nitrogen is 1 : 4.
- The ratio of chlorine to nitrogen is 1 : 4.
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- What type of bonding forms an ammonia, NH₃, molecule?
- 'covalent bonding' ✓
- Which of the following are examples of physical properties of a substance?
- Melting point ✓
- Electrical conductivity ✓
- pH
- Reaction with oxygen
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Exit quiz
- Match the following terms to the correct definition.
- Toxic⇔A poisonous substance that causes harm or death to living organisms. ✓
- Corrosive⇔A substance that causes damage by chemical action. ✓
- Alkaline⇔A base soluble in water producing a solution with a pH greater than 7. ✓
- Hydrogen chloride reacts with ammonia to form ammonium chloride, NH₄Cl. Which of the following chemical equations shows this reaction correctly?
- HCl + NH₃ → NH₄Cl ✓
- NH₄Cl → HCl + NH₃
- NH₄Cl + NH₃ → HCl
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What does this hazard warning symbol tell you about a substance?- It is corrosive. ✓
- It is toxic.
- It is explosive.
- It is flammable.
- It is a moderate hazard.
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- A student places a piece of damp red litmus paper in ammonia gas. Which of the following statements about this activity are correct?
- The litmus paper will turn blue. ✓
- Ammonia is an alkaline gas. ✓
- The litmus paper will remain red.
- Ammonia is an acidic gas.
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- Which of the following are examples of chemical properties of ammonia?
- Ammonia is a colourless gas at room temperature.
- Ammonia gas has an approximate pH of 11. ✓
- The boiling point of ammonia is -33 °C.
- Ammonia neutralises nitric acid. ✓
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- Ammonia is a toxic gas. What control measures, or precautions, can be taken in a lab to limit the risk?
- Use a fume cupboard. ✓
- Use a well ventilated area. ✓
- Wash in plenty of water.
- Remove contaminated clothing.
- Wear safety goggles.
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Worksheet
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Video
Lesson Details
Key learning points
- Ammonia can be synthesised in the lab by heating a mixture of NH₄Cl and NaOH, producing NH₃ gas and other by-products.
- Ammonia is an alkaline gas that reacts readily with water to form a corrosive, basic solution.
- Ammonia gas turns moist red litmus paper blue, indicating its alkaline nature.
- Ammonia gas is soluble, toxic, and has a pungent smell, requiring careful handling.
- Ammonia reacts with hydrogen chloride (from concentrated hydrochloric acid) to form white fumes of ammonium chloride.
Common misconception
Pupils may think ammonia is safe to handle without precautions because it's a common household chemical.
Emphasise ammonia's toxicity and the importance of using PPE and proper ventilation.
Keywords
Ammonia - a simple molecular substance, with the formula NH₃, is a soluble, toxic, pungent gas at room temperature.
Alkaline - a base that dissolves in water; these solutions have a pH greater than 7
Pungent - a description of a substance that has a sharply strong smell
Toxic - a substance that is poisonous, and can cause harm or death to living organisms
Corrosive - a substance that causes damage by chemical action, often resulting in severe injury or destruction
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