Chemical Analysis Flashcards

1
Q

What is a pure substance

A

A substance made of only one type of element or compound

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2
Q

What are fixed points

A

Fixed points are melting and boiling points of an element or compound

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3
Q

What happens to the melting point if a substance becomes impure

A

Melting point decreases

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4
Q

What happens to the boiling point if a substance becomes impure

A

Increases

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5
Q

What is a formulation

A

A mixture that is designed to be useful

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6
Q

Give two examples of formulations

A

Paint
Cleaning agents

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7
Q

What is the technique used to analyse unknown substances in solution

A

Chromatography

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8
Q

What are the two phases in chromatography

A

Mobile phase and stationary phase

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9
Q

What does Rf mean

A

Retention Factor

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10
Q

How can we work out the Rf value of a substance

A

Rf = Distance move by substance / Distance moved by solvent

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11
Q

How can a substance be identified by its Rf value

A

The Rf value can be matched against a database

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12
Q

What is the test for hydrogen and what is the positive result

A

Lighted splint is placed in test tube with hydrogen, produces a ‘pop’

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13
Q

What is the test for oxygen and what is the positive result

A

Glowing splint is placed in test tube with hydrogen, relights

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14
Q

What is the test for carbon dioxide and what is the positive result

A

Bubble through limewater, goes cloudy

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15
Q

What is the chemical name for limewater

A

Calcium hydroxide

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16
Q

What is the test for chlorine and what is the positive result

A

Reacted with damp blue litmus paper, litmus paper turns white as it is bleached

17
Q

What are the two tests that can be used to test for positive ions

A

Flame test
Sodium Hydroxide

18
Q

Sodium ion flame colour

A

Yellow

19
Q

Lithium ion flame colour

A

Crimson

20
Q

Potassium ion flame colour

A

Lilac

21
Q

Copper ion flame colour

A

Green

22
Q

Calcium ion flame colour

A

Orange-red

23
Q

How to test for halide ions

A

Dilute nitric acid, then add silver nitrate
Iodine - Yellow
Bromine - Creamy
Chlorine - White

24
Q

How to test for sulfate ions

A

Add dilute nitric acid, then add barium chloride.

If present, white precipitate will form