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Diamonds are very hard, they are often used as an abrasive.

Endothermic reactions are those reactions which absorb energy from the surroundings and result in a net decrease in temperature.

The formula to calculate the dilution factor when using concentrations is DF = \(\frac{C_1}{C_2}\), where C\(_1\) is the initial concentration of the stock solution and C\(_2\) is the final concentration of the diluted solution. Dilution factor= \(\frac{0.1}{0.001}\) = 100

A diamond is pure carbon. Graphite is pure carbon. Both will burn to form carbon dioxide.

In a saturated solution dissolved solute and undissolved solute are in equilibrium with each other. Is different from A saturated solution is said to be in equilibrium with undissolved solute when the rate of dissolution of the solute equals the rate of crystallization. This means that the amount of solute being dissolved is the same as the amount of solute coming out of solution, resulting in no net change in the concentration of the solution.

1 mole = \(6.02 \times 10^{23}\) 2.5 moles = \(6.02 \times 10^{23} \times 2.5\) = \(15.05 \times 10^{23} = 1.505 \times 10^{24}\) \(\approxeq 1.5 \times 10^{24}\)

The Magnesium actually reacts with oxygen in the air, is burnt and produces a bright light. The bright light emits a lot of heat so the reaction is exothermic.

The compound CO is treated as a neutral oxide, though in truth, it is slightly acidic. Regardless of this, within the options supplied, CO is the best option available.

The percentage of Carbon in the compound is (100 - 14.3)% = 85.7% C : H \(\frac{85.7}{12.0} : \frac{14.3}{1.0}\) \( 7.14 : 14.3\) \(\frac{7.14}{7.14} : \frac{14.3}{7.14}\) \(\approxeq 1 : 2\) Therefore, the empirical formula is \(CH_{2}\).

Ammonium salts react with bases to release ammonia and not with acids.

The word "halogen" is a Greek word meaning salt former, because they form salts when they react with metals eg NaCl.

For a substance to conduct electricity, it must have charge particles like electrons and ions within it that are able to move freely throughout it. In its solid state, potassium chloride (like many other ionic compounds) have fixed ions, hence, they are immobile and can't conduct electricity.

When water is added to white coloured anhydrous copper sulphate, its colour changes to blue, indicating that the blue coloured copper sulphate pentahydrate is regenerated.

No expanded working has been attached for this question yet. The verified answer is Option C.

Solubility in \(gdm^{-3}\) = \(\frac{mass of salt in gram}{volume of liquid in dm^{3}}\) 200\(cm^{3}\) = \(\frac{200}{1000} dm^{3} = 0.2dm^{3}\) Solubility = \(\frac{0.2g}{0.2dm^{3}}\) = 1.0\(gdm^{-3}\)