C3 Topic 1

Qualitative analysis tells you what substances are present. This can be used to detect poision and you don't need to know the quantity as a trace could be a problem. 

Quantative analysis tells you how much substance is present. This can be used by the police to know how much alcohol is present in a drivers body. If it's greater than 80mg per 100 ml of blood, the driver can be prosecuted. 

Tests: Oxygen-glowing splint relights

Acid:universal indicator turns red

Carbon dioxide: gas passed through delivery tube to test tube turning limewater cloudy. 

Alkali: unviersal indicator turns purple

Hydrgen: makes a squeaky pop with lighted splint. 

Carbonate Test: Place the unknown substance into the conical flask which is closed off with a bung and delivery tube. If it's a carbonate, the gas produce will be carbon dioxide which will turn the limewater in the test tube cloudy. Acid + carbonate goes to from salt+water+carbon dioxide.

Sulphate ions: Place the unknown substance into the test tube, add dilute hydrochloric acid and barium chloride. If a white precipitate forms; then the unknown substance was a sulphate.

Chloride ions: Place the unknown substance into a test tube add diluted nitric acid and silver nitrate solution. If the unknown substance was a chloride, a white precipitate will form a silver chloride.

Spectroscopy: When elements are heated, they produce a spectrum of light. The spectrum of light is unique to each element so you can identify the element even if it's a small amount. It is fast, reliable and it ca detect even the most smallest amount.

Flame Test: 1. Take a nichrome wire and place it into hydrocholric acid to sterile the wire. 

2. Dip the nichrome wire into the unknown substance.

3. Place the wire into the blue part of the bunsen burner flame.

4. Record the colour observed.

5. Repeat step 1

 Results: 

…