6 (a) Methane is a hydrocarbon fuel - Edexcel - GCSE Chemistry - Question 6 - 2020 - Paper 1

Carbon and carbon monoxide are produced in the incomplete combustion of methane due to insufficient oxygen being available. When methane does not receive enough oxygen during combustion, it cannot fully convert to carbon dioxide, resulting in the formation of carbon as soot and carbon monoxide, which is a toxic byproduct.

The fraction used to surface roads is bitumen.

The fraction that contains hydrocarbons with the lowest boiling point is gases.

The correct option is A: kerosene, diesel oil, bitumen.

In the cracking reaction:

C8H18 → C6H14 + CxHy

We can determine the value of 'x' by balancing the carbon atoms:

From the left side, we have 8 carbon atoms in octane. From the right side, we have 6 carbon atoms in C6H14, so:

8 (total carbons) = 6 (from C6H14) + x;

This simplifies to:

x = 8 - 6 = 2.

Thus, the value of x in the molecule of CxHy is 2.

To calculate the maximum mass of octane that can be produced from 340g of dodecane, we first need to find out how many moles of dodecane are present:

Molar mass of dodecane (C12H26) = 170 g/mol.

Moles of dodecane = mass / molar mass = 340 g / 170 g/mol = 2 moles.

The reaction produces 1 mole of octane (C8H18) per mole of dodecane.

So, from 2 moles of dodecane, we can produce 2 moles of octane.

Now, calculate the mass of octane produced:

Molar mass of octane = 114 g/mol.

Mass of octane = moles × molar mass = 2 moles × 114 g/mol = 228 g.

Therefore, the maximum mass of octane that could be produced is 228g.