- When a mixture of carbon and copper(II) oxide is heated strongly
- I the oxide ion loses two electrons.
- II the oxidation number of carbon increases from 0 to +4
- III the copper(II) oxide acts as the reducing agent.
- IV the copper(II) ion accepts two electrons
- The chemical equation shows the decomposition of a copper(II) nitrate salt.
2Cu(NO3)2 à 2CuO + 4NO2 + O2
What is the volume of nitrogen dioxide, NO2 gas at room condition if 0.2 mol of Cu(NO3)2 salt is heated.
[Molar volume = 24 dm3 mol-1 at room conditions]
- 1.2 dm3
- 2.4 dm3
- 4.8 dm3
- 9.6 dm3
- Table below shows the electron arrangement of atom P and atom Q.
Atom Electron arrangement P 2.8.2 Q 2.8.7
- Element P reacts with element Q to form a compound. Which of the following is not true about the reaction?
- Atom P donates 2 electrons.;
- Atom Q receives 1 electron.
- PQ2 compound is formed.
- The forces of attraction between the particles in the compound formed is weak.
- Effective collision is the collision where
- its energy is less than the activation energy and with correct orientation
- has a low energy
- its energy is equal to the activation energy
- its energy is greater than the activation energy with the correct orientation
- Table below shows the substances used to study the rate of reaction between marble and nitric acid.
Experiment Substance I Excess marble and 50 cm3 of 0.2 mol dm-3 nitric acid II Excess marble and 100 cm3 of 0.1 mol dm-3 nitric acid
Which of the following graphs represents the two experiments?
- A student wants to make her ring more beautiful and durable. What is the best way to do it?
- Brush the ring with sandpaper
- Wash the ring with detergent
- Plate the ring with silver
- Immerse the ring in acid
- Diagram below shows the set-up of apparatus to investigate the effect of heating on a salt.
Which of the following is true about the salt?
- Nitrogen dioxide gas is liberated
- Carbon dioxide gas is liberated
- Lead(II) oxide is formed
- The black residue is formed
- The aircraft tyres are made from vulcanized rubber What property of vulcanized rubber makes it suitable to be used for making these aircraft tyres?
- It can take the tremendous stress and strength
- It is harder and stronger
- It resist to the oxidation
- It can maintain their elasticity
- The diagram shows a reaction between copper metal and silver nitrate solution.
Which of the following is true?
- Copper is oxidised
- Brown solid deposited on copper
- Blue colour of solution turns
- Oxidation number of silver increases 0 to +4
- Diagram below below shows the molecular formula of two cleaning agent, X and Y.
Cleaning agent X: CH3(CH2)14COONa
Cleaning agent Y: CH3(CH2)11OSO3Na
What statement about X and Y is correct?