CIE iGCSE Co-Ordinated Science C11.4 Alkanes Exam Style Questions Paper 4
Question
(a) Butane, C4H10, is an alkane.
Complete the sentence about alkanes.
Alkanes are ………………………………………….. hydrocarbons whose molecules contain
only ………………………………………….. covalent bonds.
(b) Table 11.1 shows the energy given out when 1g of different alkanes burns.
(i) State the relationship between the number of carbon atoms in the alkane and the energy
given out.
(ii) State the name given to any reaction that gives out energy.
(c) Butane is a small alkane molecule. Large alkane molecules are cracked into smaller, more useful molecules. The equation shows the cracking of C24H50 to make C10H22 and one other product.
Complete the equation.
C24H50 C10H22 + ……………
(d) Table 11.2 shows the percentage (%) supply and demand for some of the different fractions
obtained from crude oil.
Suggest and explain which fraction is cracked to obtain more gasoline (petrol).
▶️Answer/Explanation
Ans : 11(a) saturated ;
single;
11(b)(i) idea that the higher the number of carbon atoms the lower the energy given out / ORA ✓
11(b)(ii) exothermic ;
11(c) C14H28 ;
11(d) fuel oil / kerosene / naphtha ;
idea that the supply is greater than the demand ;