During electrolysis of water, a student notices that one test tube collects approximately twice as much gas as the other. Which gas is present in the larger volume?, oxygen, hydrogen, carbon dioxide, nitrogen, A sample of water obtained from different sources always contains hydrogen and oxygen in the same fixed proportion when it is pure. This shows that water is:, compound, mixture, element, solution, A substance contains two elements chemically combined in a fixed ratio. Which conclusion is most appropriate?, It is a mixture, It must be an element, It is a compound, It can be separated by filtration, In an electrolysis setup, gas X is collected at the cathode (−) and gas Y at the anode (+). Which identification is correct?, X = Oxygen, Y = Hydrogen, X = Hydrogen, Y = Oxygen, X = Nitrogen, Y = Oxygen, X = Oxygen, Y = Carbon dioxide, A student tries to separate sodium chloride into sodium and chlorine by filtration. The attempt fails. Why?, Sodium chloride is an element, Sodium chloride is a homogeneous mixture, Sodium chloride is insoluble in water, Sodium chloride is a compound and its elements are chemically combined, A student heats sugar in a boiling tube. The sugar first turns brown and later becomes black. What does the black substance mainly indicate?, Formation of carbon-rich residue, Formation of oxygen, Melting of sugar, Formation of sodium chloride

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