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C4 Predicting and identifying reactions and products

5 dot points across 5 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How do chromatography and instrumental methods identify substances, and why are instruments so useful?

Paper chromatography and Rf values applied to identifying substances, the advantages of instrumental methods of analysis, and using flame emission spectroscopy to identify and measure metal ions.
A focused answer to OCR Gateway GCSE Chemistry A topic C4.2 on identifying substances by instrumental and chromatographic methods, covering paper chromatography and Rf values, the advantages of instrumental analysis, and flame emission spectroscopy.
8 min answer →

How are metals extracted from their ores, and how does the method depend on reactivity?

Metal ores and oxidation, extracting metals by reduction with carbon, extracting reactive metals by electrolysis, the position of carbon in the reactivity series, and predicting reactions of Group 1 and Group 7 elements.
A focused answer to OCR Gateway GCSE Chemistry A topic C4.1 on extracting metals and predicting reactions, covering metal ores, extraction by reduction with carbon, electrolysis of reactive metals, the role of carbon in the reactivity series, and predicting the reactions of Group 1 and Group 7 elements.
9 min answer →

How can we identify carbonate, halide and sulfate ions in a sample?

Tests for negative ions (anions): the carbonate test with acid, the halide test with silver nitrate, and the sulfate test with barium chloride, including the observations and ionic equations.
A focused answer to OCR Gateway GCSE Chemistry A topic C4.2 on tests for negative ions, covering the carbonate test using dilute acid, the halide test using silver nitrate, and the sulfate test using barium chloride, with observations and ionic equations.
8 min answer →

How can we identify metal ions and common gases by chemical tests?

Flame tests for metal ions, the use of sodium hydroxide to identify metal ions by precipitate colour, and the tests for hydrogen, oxygen, carbon dioxide, chlorine and ammonia.
A focused answer to OCR Gateway GCSE Chemistry A topic C4.2 on identifying substances, covering flame tests for metal ions, identifying metal ions using sodium hydroxide precipitates, and the tests for hydrogen, oxygen, carbon dioxide, chlorine and ammonia.
9 min answer →

How does the reactivity series let us predict the reactions of metals?

The reactivity series of metals, the reactions of metals with water, oxygen and acids, displacement reactions, and using the reactivity series to predict reactions.
A focused answer to OCR Gateway GCSE Chemistry A topic C4.1 on the reactivity series, covering the order of metal reactivity, the reactions of metals with water, oxygen and acids, displacement reactions, and using the series to predict whether a reaction will happen.
9 min answer →