C17 Chemical Analysis Flashcards
Define what a pure substance is
a pure substance consists only of one element or one compound
Define what a mixture is
a mixture consists of two or more different substances, not chemically joined together
Define what a formulation is and give examples
Definition - a mixture which has been designed as a useful product.
Uses - fuels, cleaning products, paints, medicines, alloys, fertilisers, foods
Equation for Rf value
Rf = distance moved by substance / distance moved by solvent
In a lab experiment of chromatography what 2 things represent the stationary phase and mobile phase
Stationary phase - Paper
Mobile phase - water
Test for hydrogen and results if present
Squeaky pop test - hold a lit splint near the gas (you will hear a squeak if hydrogen is present)
Test for oxygen and results if present
Hold a glowing splint near the gas, the splint will re-light if oxygen is present
Test for carbon dioxide and results if present
Bubble the gas through limewater, the limewater will turn cloudy if carbon dioxide is present
Test for chlorine and results if present
Hold a piece of damp litmus paper near the gas, the litmus is bleached white if chlorine is present
Flame colour of lithium ions in a flame test
Crimson
Flame colour of sodium ions in a flame test
Yellow
Flame colour of potassium ions in a flame test
Lilac
Flame colour of calcium ions in a flame test
Orange-red
Flame colour of copper ions in a flame test
Green
Test for aluminium cations
- Slow addition of sodium hydroxide solution - White precipitate formed
- Eventually dissolves again with excess sodium hydroxide
