Chem chp1 Flashcards

1
Q

How many methods for collecting gases are there?

A

4

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2
Q

What are the methods for gas collection?

A

Water displacement, Downward delivery, Upward delivery, using gas syringe

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3
Q

What is Water displacement used for?

A

To collect insoluble or slightly soluble gases.

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4
Q

Does density affect Water displacement gas collection?

A

No

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5
Q

What is Downward delivery gas collection method used to collect?

A

Gases denser than air and soluble in water

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6
Q

Is the gas jar sealed during downward delivery?

A

No

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7
Q

What is upward delivery used for?

A

To collect air less dense than air and soluble in water.

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8
Q

Is gas jar sealed during upward delivery?

A

No

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9
Q

What is use of gas syringe collection method used for?

A

To measure and collect any type of gas.

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10
Q

How many drying agents for gases are there?

A

3

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11
Q

What should concentrated sulfuric acid be used for?

A

To dry acidic gases

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12
Q

What should quicklime drying agent be used for?

A

To dry alkaline gases

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13
Q

How does quicklime dry the gas?

A

It absorbs moisture and carbon dioxide from air

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14
Q

What is another name for fused calcium chloride?

A

Anhydrous calcium chloride

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15
Q

What is fused calcium chloride used for?

A

To dry neutral gases

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16
Q

How does fused calcium chloride dry the gas?

A

It absorbs moisture from air

17
Q

Which 2 drying agents have to be freshly heated before use?

A

Quicklime and Fused calcium chloride

18
Q

Define mixture

A

A substance that is made up of two or more substances that are not chemically combined

19
Q

What is a pure substance made up of?

A

One single element or compound, not mixed with any other substance.

20
Q

What are the different types of mixtures?

A

Liquid-liquid, solid-solid, solid-liquid.

21
Q

What separation techniques can be used on solid-solid mixtures?

A

Magnetic attraction, sieving, using solvents, sublimation

22
Q

What separation techniques can be used on solid-liquid mixtures?

A

Filtration, evaporation to dryness, crystallisation, simple distillation

23
Q

What separation techniques can be used on liquid-liquid mixtures?

A

Using separating funnel, chromatography, fractional distillation

24
Q

Define solvent

A

A liquid that dissolves solids (solute)

25
Q

Define solute

A

Solids that dissolve in solvent.

26
Q

Define solubility

A

The ability of a solute to dissolve in a solvent

27
Q

Define sublimation

A

A process in which a substance changes from a solid to gas without passing through the liquid state

28
Q

Describe the sublimation experiment

A

Solid sublimes into gas-> moves away form mixture
Cool surface provided-> gas changes back to solid

29
Q

In filtration, what do you call the mixture collected in the beaker?

A

The filtrate

30
Q

In filtration, what do you call the solid that remains on the filter paper?

A

Residue

31
Q

What are miscible liquids?

A

Liquids which form a uniform (/homogenous) solution when mixed together

32
Q

What is a heterogenous mixture?

A

A mixture which contains **immiscible liquids **that do not form a uniform solution.

33
Q

What do you call the layers which immiscible liquids separate into?

A

Phases

34
Q

What does Rf value stand for?

A

Retention factor

35
Q

What is Rf value refer to in a substance?

A

The measure of the substance’s solubility in a solvent.

36
Q

What is the formula for Rf value?

A

distance travelled by substance/ distance travelled by solvent

37
Q

What is the difference between fractional distillation and simple distillation?

A

Fractional distillation is used to separate two miscible liquids with different boiling points, while simple distillation is used to separate a pure solvent from a solution.

38
Q

What are the three ways to test for purity of substances?

A

Melting point of solid, boiling point of solid, chromatography.

39
Q

What happens to melting and boiling point when containing impurities?

A

Melting point decrease, boiling point increase