chemistry atar exam year 11 unit 1 questions & answers 2024/25

chemistry atar exam year 11 unit 1 questions & answers 2024/25 - ANSWERSrepresented by symbols materials - ANSWERSpure substances with distinct measurable properties, including melting and boiling points, reactivity, hardness and density; or mixtures with properties dependent on the identity and relative amounts of the substances that make up the mixture pure substances - ANSWERSelements or compounds which consist of atoms of two or more elements chemically combined; the formulae of compounds indicate the relative numbers of atoms of each element in the compound nano materials - ANSWERSsubstances that contain particles in the size range 1-100 nm and have specific properties relating to the size of these particles which may differ from those of the bulk material dangers of nano materials - ANSWERSNanoparticles are able to travel through skin into the blood stream and even cells. Unwanted biochemical reactions can occur when nanoparticles interact with biomolecules inside the body Similarly, nanoparticles may accumulate in the food chain, so there are potential environmental risks top down fabrication - ANSWERS•Start with large piece (which is cheap to produce) and progressively remove material until required size and shape achieved. •Most common •Used to make computer chips and sunscreen bottom up fabrication - ANSWERSRequires making the material atom by atom