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1 PCS Mini Car Air Ion Tester Meter Counter Air Ion Tester Meter Counter for Negative Air Ion Generator with a Necklace

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grades 9–12 K12 advanced subsidiary chemistry course etc. and help you to identify unknown inorganic and organic This time, only the zinc hydroxide precipitate redissolves - for the same reason that the copper(II) hydroxide that we have already looked at dissolves in excess ammonia solution.

The presence of the hydroxide ions means that you might expect ammonia solution to react with metal ions in the same way as sodium hydroxide solution. With this test, you can compare the reaction time of one person at different times or compare the results of different people.

Note: Strictly speaking this should be the [Cu(NH 3) 4(H 2O) 2] 2+ ion. At this level, all you may be expected to know is its deep blue colour. What is happening here is that the excess ammonia solution reacts with the copper(II) ions to give the deep blue soluble ion [Cu(NH 3) 4] 2+ where ammonia molecules have attached themselves to the copper ion. You start with a solution of your compound and then add a few drops of sodium hydroxide solution or ammonia solution. Note what happens. This also works perfectly well if you add the sodium hydroxide solution to some solid containing ammonium ions and warm that mixture.

Remember that your speed on this test is the sum of the reaction time of your brain and the movement of your finger to press the button.

The video shows what happens when you add sodium hydroxide solution to these three ions (and also to Al 3+ ions - ignore that for now.) In each case the formation of the precipitates involves exactly the same chemistry as with sodium hydroxide solution. All that matters is the presence of the hydroxide ions, not where they came from. Again, the precipitates are the metal hydroxides. Remember that ammonia solution contains some hydroxide ions. newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}}}\) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash{#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\)

There are two useful short pieces of video showing what happens in these reactions. They look at the aluminium ion reactions first, followed by the zinc ion reactions. Ammonia solution contains far fewer hydroxide ions than sodium hydroxide solution of the same concentration. So you don't form enough calcium hydroxide to form a reasonable precipitate. This reaction speed test is not very scientific, but just for fun and practice. How to do time reaction test You can test for ammonium ions either in a solid or in solution by adding sodium hydroxide solution and warming gently. Magnesium ions give a white precipitate insoluble in excess in both sodium hydroxide or ammonia solution.So both of these give a white precipitate of the metal hydroxide and they both dissolve in excess sodium hydroxide to give a colourless solution.

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