Chemical analysis Flashcards

1
Q

What is the difference between a pure substance and a mixture

A

Pure - a substance which consists of a single element or compound
Mixture - two or more different substances, not chemically bonded

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2
Q

How can you tell the difference between a pure substance and a mixture

A

A pure substance will have a fixed melting point
A mixture will have a range of melting points

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3
Q

What is a formulation and what are some examples

A

A mixture that has been designed as a useful product

Fuels
Medicine
Fertiliser

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4
Q

Required practical : Chromatography

What is the method

A

Pour 1 cm of water into a beaker
Draw a pencil to draw a line 1.5 cm from the bottom of the chromatography paper
Put the solvent on the line using a capillary tube and label it underneath in pencil
Wrap the top of the paper on a splint and hold it together with a paperclip and put into the beaker
Take out the paper once the water reaches ¾ of the paper and let it dry

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5
Q

Required practical : Chromatography

What are the phases

A

Mobile - solvent moving through the paper, carrying different substances with it
Stationary - contained on the paper and doesn’t move through it

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6
Q

Required practical : Chromatography

How do you calculate the Rf value

A

Distance travelled by substance / distance travelled by solvent

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7
Q

How do you test for oxygen and what is the expected outcome

A

Place a glowing splint into the tube

Splint relights

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8
Q

How do you test for hydrogen and what is the expected outcome

A

Place a burning splint into the tube

Create a pop sound

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9
Q

How do you test for carbon dioxide and what is the expected outcome

A

Bubble gas through lime water

Lime water will go from clear to cloudy

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