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Bicarbonate indicator. A hydrogencarbonate indicator (hydrogencarbonate indicator) is a type of pH indicator that is sensitive enough to show a color change as the concentration of carbon dioxide gas in an aqueous solution increases. The indicator is used in photosynthesis and respiration experiments to find out whether carbon dioxide is being ...
Until 2014, the Standard Grade section of the site had 12 subjects: Biology, History, Chemistry, Computing Studies, Maths, English, Modern Studies (a course exclusive to Scotland), French, Physical Education, Geography, and Physics. [9] The site was updated in 2014 to replace the Standard Grade section with National 4 and National 5 sections.
Combined Science results in two GCSEs. Those with GCSEs in Combined Science can progress to A Levels in all of the three natural science subjects. Prior to this, around 1996, Combined Science GCSEs were available as an alternative to three separate Sciences for many exam boards. Combined Science consists of either Higher Tier (HT) or Foundation ...
A flame test is relatively quick test for the presence of some elements in a sample. The technique is archaic and of questionable reliability, but once was a component of qualitative inorganic analysis. The phenomenon is related to pyrotechnics and atomic emission spectroscopy. [1] The color of the flames is understood through the principles of ...
Filtration is used to separate particles and fluid in a suspension, where the fluid can be a liquid, a gas or a supercritical fluid. Depending on the application, either one or both of the components may be isolated. Filtration, as a physical operation enables materials of different chemical compositions to be separated.
Gas exchange is the physical process by which gases move passively by diffusion across a surface. For example, this surface might be the air/water interface of a water body, the surface of a gas bubble in a liquid, a gas-permeable membrane, or a biological membrane that forms the boundary between an organism and its extracellular environment.
At 25 °C (77°F), solutions with a pH less than 7 are acidic, and solutions with a pH greater than 7 are basic. Solutions with a pH of 7 at 25 °C are neutral (i.e. have the same concentration of H + ions as OH − ions, i.e. the same as pure water). The neutral value of the pH depends on the temperature and is lower than 7 if the temperature ...
A packaging gas is used to pack sensitive materials such as food into a modified atmosphere environment. The gas used is usually inert, or of a nature that protects the integrity of the packaged goods, inhibiting unwanted chemical reactions such as food spoilage or oxidation. Some may also serve as a propellant for aerosol sprays like cans of ...