chap1, form4 Flashcards
definition of chemistry
A field of science that studies structures, properties, compositions, interactions bw matter
definition of diffusion
A process of spreading a substance from a region of high concentration to a region of low concentration
how do we dispose low concentration of hydrogen peroxide?
down the sink
how do we dispose high concentration of hydrogen peroxide?
dilute with water and NaSO4
where do we throw solid wastes?
special containers
how to dispose organic solvents and hydrocarbon
special containers
how to dispose heavy metals
container
how to dispose toxic substances
plastic bag, fume chamber
how to dispose substance pH<5, pH >9
closed labelled containers
how to dispose volatile substance like alcohol, bromine, ammonia
closed containers away from heat
what are the steps in a scientific investigation
observation-inference-problem-hypothesis-identifying variable-plan experiment-collect data - interpret data-conclusion-report
what is the emergency management procedure?
inform teacher -prohibit students from area- stop spill, by spreading sulphur powder, clean chemical spill, dispose chemical
diffusion in solid of a test tube containing crystals of CuSO4, what is observed?
blue colour of CuSO4 fills up test tube
why does the test tube turn blue?
Cu2+ ions and SO42- ions are present and diffuse randomly upwards turning agar blue
diffusion in liquid of KMnO4, what is observed?
purple colour of KMnO4, fills up test tube
