Basic Concepts of ChemistryElements, Compounds and Mixtures21Choose the best answerIn known elements, the maximum number is of:AMetalsBNon-metalsCMetalloidsDNone of these Like 1 Discuss 0Share
Basic Concepts of ChemistryPhysical and Chemical Changes22Choose the best answerWhich of the following are chemical processes? 1. Rusting of a nail 2. Freezing of water 3. Decomposition of water into hydrogen and oxygen 4. Compression of oxygen gasA2, 3 and 4B1, 3 and 4C1 and 3D1 and 2 Like 0 Discuss 0Share
Basic Concepts of ChemistryPhysical and Chemical Changes23Choose the best answerWhich of the following is a characteristic of a chemical change?AFormation of one or more new substancesBNo energy change can occurCChemical composition remains unchangedDOnly the physical state changes Like 0 Discuss 0Share
Basic Concepts of ChemistryPhysical and Chemical Changes24Choose the best answerA chemical change results in:ALoss of matterBSolutionCPhase changeDFormation of different kinds of matter Like 0 Discuss 0Share
Basic Concepts of ChemistryPhysical and Chemical Changes25Choose the best answerLiquid → Solid is called:AMeltingBBoilingCFreezingDDeposition Like 0 Discuss 0Share