Pure Substances (GCSE Chemistry)

When excess solid carbonate remains after adding it to acid to make a salt, which observation would show that the carbonate is in excess?

Which simple test and result identify oxygen gas in a laboratory test?

Which statement about chromatography Rf values is correct?

Which result shows that a solid sample contains carbonate ions when treated with dilute acid?

Which reagent and observation indicate the presence of sulfate ions in an aqueous sample?

Which instrument separates ions by mass and can identify isotopes and relative atomic masses?

What is one clear advantage of using an instrumental technique (e.g., flame emission spectroscopy) rather than just a simple chemical test to detect metal ions?

How is the chromatographic Rf value calculated for a spot on paper chromatography?

Which test result indicates the presence of ammonia gas?

Which simple laboratory observation most strongly suggests that a sample of water is pure distilled water rather than tap water?

How can the pale lilac flame of potassium be more easily seen when sodium contamination produces a strong yellow flame?