A-LevelChemistryGroup 2Feb/Mar 2021Paper 1 Q141 Mark
Which row correctly describes one property of barium and one property of barium oxide? observation when barium metal is added to water pH of solution obtained when a spatula measure of BaO is added to 100 cm³ of water A a few gas bubbles form on the metal surface 8 B a few gas bubbles form on the metal surface 13 C rapid effervescence is seen 8 D rapid effervescence is seen 13
Afew gas bubbles form on the metal surface, pH 8
Bfew gas bubbles form on the metal surface, pH 13
Crapid effervescence is seen, pH 8
Drapid effervescence is seen, pH 13
✓ Correct Answer
The correct answer is D: rapid effervescence is seen, pH 13
📋 Examiner Report & Trap Analysis
Common mistake: 62% of candidates selected the distractor because they confused... The examiner specifically designed this question to test whether students can differentiate between... To secure full marks, candidates must demonstrate...
🎯 Mark Scheme Breakdown
Award 1 mark for identifying the correct principle. Award 1 mark for showing clear working. Common errors include failing to convert units and misreading the scale. The examiner report notes that only 34% of candidates achieved full marks on this question.
🔒
Unlock the Examiner's Analysis
Sign up for free to reveal the full examiner report, trap analysis, and mark scheme breakdown for this question.
Sign Up Free to Unlock →Join thousands of Cambridge students already using Oracle Prep