DP Chemistry (last assessment 2024)

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Question 19M.3.hl.TZ1.17a

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Date May 2019 Marks available [Maximum mark: 1] Reference code 19M.3.hl.TZ1.17a
Level hl Paper 3 Time zone TZ1
Command term Outline Question number a Adapted from N/A
a.
[Maximum mark: 1]
19M.3.hl.TZ1.17a

E10 is composed of 10% ethanol and 90% normal unleaded fuel.

(a)

Ethanol has a Research Octane Number (RON) of 108.6.

Outline how higher octane fuels affect engine performance.

[1]

Markscheme

increased AND fuels can be compressed more «before ignition»   [✔]

 

Note: Accept “engines can be designed with higher compression ratio” OR “less chance of pre-ignition/auto-ignition/knocking occurring”.

Examiners report

One G2 respondent was concerned that “Research Octane Number” was used instead of “Octane Rating”, but most candidates correctly outlined how higher octane fuels affect engine performance.

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