Qualitative Analysis
Qualitative Analysis
Qualitative is where the results give a colour that you have to match up to a colour chart, or have you have done to see if it is positive or negative with a description of what a positive reaction should look like. This test is less reliable as some colour or positive reaction look similar to each other or the same but by adding different chemicals. An example of qualitative would be a pH test as the result gives you a colour and then you have to match it up to the pH scale to get you final result.
Qualitative analysis is used to find out different ion in a given sample. This also analytical chemistry technique, this testing method uses many different tests to get a reaction that would link with different ions.
Ions
An Ion is an electrically charged particles that are formed when atoms are added or taken way. Metal atoms have positively charged ions and non-metal atoms have negatively charged ions. To work out how many ions a metal and non-metal should have is simple. Metals should have the same amount of charged ions as the group number they are in for example a metal in group 2 will have two positively charged ions. Non-metals should have the same amount of charged ions as the group number they are in but minus eight for example a non-metal in group 5 would have 3 negatively charged ions. Negative ions are called anions and positive ions are called cations.
When testing for cations/metals you could use a flame test this is the simplest and quickest way of test for cations another way that you could test for cations is a sodium hydroxide test this test consist of adding sodium hydroxide to test compound when coloured precipitate is formed them stop adding the sodium hydroxide and see what the cation is by using the table below, this table show what colour the precipitate is and any further results.
Anion
Precipitate colour
Further results
Aluminium
Al3+
White
Precipitate dissolves as more NaOH is added to the
Qualitative is where the results give a colour that you have to match up to a colour chart, or have you have done to see if it is positive or negative with a description of what a positive reaction should look like. This test is less reliable as some colour or positive reaction look similar to each other or the same but by adding different chemicals. An example of qualitative would be a pH test as the result gives you a colour and then you have to match it up to the pH scale to get you final result.
Qualitative analysis is used to find out different ion in a given sample. This also analytical chemistry technique, this testing method uses many different tests to get a reaction that would link with different ions.
Ions
An Ion is an electrically charged particles that are formed when atoms are added or taken way. Metal atoms have positively charged ions and non-metal atoms have negatively charged ions. To work out how many ions a metal and non-metal should have is simple. Metals should have the same amount of charged ions as the group number they are in for example a metal in group 2 will have two positively charged ions. Non-metals should have the same amount of charged ions as the group number they are in but minus eight for example a non-metal in group 5 would have 3 negatively charged ions. Negative ions are called anions and positive ions are called cations.
When testing for cations/metals you could use a flame test this is the simplest and quickest way of test for cations another way that you could test for cations is a sodium hydroxide test this test consist of adding sodium hydroxide to test compound when coloured precipitate is formed them stop adding the sodium hydroxide and see what the cation is by using the table below, this table show what colour the precipitate is and any further results.
Anion
Precipitate colour
Further results
Aluminium
Al3+
White
Precipitate dissolves as more NaOH is added to the