- Lai ManLv 51 十年前最愛解答
oxygen is a kind of element in chemistry which is a gas
the colour in every temperature is colourless
there is no smelly in oxygen
the melting point is-218.79 °C
the uses of daily life can divide in two part
first in industry oxygen (can cut and welding metal)
Second for breathing(eg.we need oxygen to carry out the respiration)
third in rockets and space shuttles(Liquid oxygen is the most important on rockets,is a kind of fuel)
The word "hydrogen" means different things to different people, leading too much confusion.
-Hydrogen is the name of an element
-Hydrogen is a diatomic molecule that would be a convenient fuel except that it occurs naturally only in trace amounts and must be extracted from other sources, such as fossil fuels; chemists increasingly refer to H2 as dihydrogen to distinguish this molecule from atomic hydrogen and hydrogen found in other compounds,
-Hydrogen is atomic constituent within all organic compounds, water, and many other chemical compounds.
-Hydrogen is the lightest chemical element; its most common isotope comprises just one negatively charged electron, distributed around a positively charged proton (the nucleus of the hydrogen atom - all other atoms have more complex nuclei involving more protons or neutrons).
Carbon dioxide is a substance that combine one carbon and two oxygen molecule.
When it frozen, carbon dioxide will form a solid called dry ice, carbon dioxide can not be liquidize, it go from the solid states to gas states directly.
Carbon dioxide is tasteless and perhap colorless. As animal, when cell respiration take place, carbon dioxide is produced; when we burning fire or fossil fuel, some carbon dioxide will also release. When the rainfall, the mixture of rain and CO2 will form a carbonic acid.