Chemical analysis Flashcards

1
Q

What is a formulation?

A

A mixture that has been designed as a useful product. Carefully controlled quantitities of each substance are added to ensure the product has the required properties.

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2
Q

Examples of formulations

A

Alloys, fertilizers, fuels, medecines, foods, paints and cleaning agents.

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3
Q

What is a sharp melting point?

A

One specific temperature

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4
Q

What is the diffrence between the melting poins of mixtures and pure substances?

A

Mixtures melt over a range of temps but pure substances have a sharp melting point.

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5
Q

-Test for hydrogen
-Test for chlorine
-Test for Carbon dioxide
-Test for water vapour

-Test for ammonia
Test for oxygen

A

-Burns with a squeaky pop
-Bleaches litmus paper
-Turns limewater milky
-Turns anhrydrous copper sulfate from white to blue
-Turns damp red litmus to blue
-Relights a glowing splint

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6
Q

What’s an element

A

When only one type of atom is present (Sodium)

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7
Q

What’s a mixture

A

Two or more elements that aren’t chemically combined

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8
Q

What’s a compound

A

Two or more elements that are chemically combined

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9
Q

What is decanting? Give an example.

A

Liquid from an insoluble solid. sand + water

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10
Q

What is filtration? Give an example.

A

Insoluble solid from a liquid. sand + water

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11
Q

What is evaporation? Give an example.

A

Solute from a solution. Salt from salt solution

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12
Q

What is distillation? Give an example.

A

Solvent from a solution. Water from salt solution

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13
Q

What is fractional distillation? Give an example.

A

Mixture of miscible liquids. Petrol + diesel from crude oil.

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14
Q

What is a separating funnel? Give an example.

A

Mixture of immiscible liquids. Oil and water

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15
Q

What is chromotography? Give an example.

A

Mixture of soluble solids. Mixture of food dyes.

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16
Q

What are the two phases of chromotography?

A

The stationary phase the part that doesn’t move and the mobile phase the part that moves.

17
Q

Explain what to do in paper chromotography

A

Draw a starting line on the paper in pencil
Small spots of each dye placed on the starting line by a glass capillary tube no more than 5mmm in diameter
Pour 0.1m sodium hydroxide in beaker
Paper left vertically in solvent below level of sample spots
Solvent soaks up paper for a few minutes.
Once solvent near the top take paper out and leave to dry.

18
Q

Why do substances in a mixture seperate?

A

Because they have different attractions to the stationary phase and mobile phase.

19
Q

Whats the formula for each distance the substance moved?

A

distance travelled by substance
——————————distance moved by solvent