Students combine several chemicals and record the observations in their science notebooks. A list of the observed results is given here. • Production of a gas (bubbles) • Phase change (solid to liquid) • A precipitate forms • Change in shape • Crystals dissolving • Heat produced How many of the observations are evidence that a new substance was formed? *
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Oxidation-reduction reactions (often called "redox" for short) are reactions that involve the transfer of electrons from one species to another. oxidation states, or oxidation numbers, allow chemists to keep track of these electron transfers. in general, one element will lose electrons (oxidation), with the result that it will increase in oxidation number, and another element will gain electrons (reduction), thereby decreasing in oxidation number. the species that is oxidized is called the reducing agent or reductant. the species that is reduced is called the oxidizing agent or oxidant. to sum up: oxidation = increase in oxidation state = loss of electrons = reducing agent reduction = decrease in oxidation state = gain of electrons = oxidizing agent part a which element is oxidized in this reaction? fe2o3+3co→2fe+3co2 enter the elemental symbol. view available hint(s) is oxidized part b which element is reduced in this reaction? 2hcl+2kmno4+3h2c2o4→6co2+2mno2+2kcl+4h2o enter the elemental symbol. view available hint(s) is reduced

Which process transfers heat from inside earth to its surface? convection currents in mantle pulling away of tectonic plates drawing in of tectonic plates convection currents in crust

Match the vocabulary terms to their definitions. 1 . a long, chain-like set of molecules made up of repeating units joined end to end polymer 2 . a hard, brittle, heat- and corrosion-resistant material made by subjecting a nonmetallic mineral mixture to intense heat ceramic 3 . a plastic with low elongations that cannot be recycled thermoset 4 . a carbon fiber embedded in a polymer resin matrix thermoplastic 5 . a plastic with high elongations that can be recycled crystal 6 . a solid form resulting from the arrangement of atoms, ions, or molecules in definite geometric patterns composite