Qualitative Analysis Flashcards

1
Q

Name a benefit of using chlorine in water treatment

A

Kills bacteria

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2
Q

What type of ions do halogens form?

A

1- halides

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3
Q

What is the outer shell electron configuration of the halogens?

A

s2 p5

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4
Q

What are the colours of Cl2, Br2 and I2 solutions in organic solvents?

A

Pale green, orange, violet

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5
Q

How does the pH of a group 2 hydroxide solution change down the group?

A

Increases - more alkaline

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6
Q

What is formed from barium reacting with nitric acid?

A

Barium nitrate - Na(NO3)2

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7
Q

What is formed from magnesium reacting with oxygen?

A

Magnesium Oxide (MgO)

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8
Q

What is formed from strontium reacting with water?

A

Strontium hydroxide - Sr(OH)2

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9
Q

Define disproportionation

A

When an element is both reduced and oxidised at the same time

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10
Q

What is the correct sequence of tests for halides, carbonates and sulphates?

A

Carbonate test with acid then sulfate test with barium ions then halide tests.

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11
Q

Identify the test for halide ions and colours of precipitates

A

Add silver nitrate; Cl is white, Br is cream, I is yellow

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12
Q

What is the trend in reactivity down group 2?

A

Increases down the group

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13
Q

What is the outer shell electron configuration of Group 2 metals?

A

s2

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14
Q

What are the products when chlorine reacts with water?

A

HClO and HCl

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15
Q

When group 2 oxides react with water what type of compound forms?

A

The hydroxide eg calcium hydroxide

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16
Q

What are the products when chlorine reacts with dilute, cold NaOH?

A

NaClO, NaCl and H2O

17
Q

Name the test and positive result for sulfate ions

A

Add aqueous barium chloride see white precipitate

18
Q

What is formed from calcium reacting with water?

A

Calcium hydroxide

19
Q

What is NaClO?

A

Sodium chlorate(I) is bleach

20
Q

Name a use of calcium hydroxide

A

Neutralising acidic soil

21
Q

Name the test and positive result for carbonate ions

A

React with dilute nitric acid; effervescence - could check with lime water turning cloudy

22
Q

Describe and explain the trend in BP from Cl to Br to I

A

Increases due to more electrons so stronger London forces

23
Q

Explain why halogens are oxidising agents

A

They gain electrons (are reduced) taking electrons from other species

24
Q

What is formed from barium reacting with oxygen?

A

Barium oxide

25
Q

Explain why group 2 metals are reducing agents

A

The elements lose electrons (are oxidised) giving these to another species

26
Q

Describe the effect of adding dilute and conc ammonia to silver halide precipitates

A

AgCl soluble in dilute NH3, AgBr soluble only in conc NH3, AgI not soluble even in conc NH3

27
Q

Name two risks of using chlorine in water treatment

A

Chlorine is toxic; can react with organic compounds in water to make carcinogenic chloroalkanes

28
Q

What ions do group 2 elements form?

A

2+

29
Q

Why are magnesium hydroxide and calcium carbonate used in antacids?

A

They neutralise stomach acid

30
Q

Which of the other halogens can bromine displace?

A

Just iodine

31
Q

What is the molecular form of all halogens?

A

Diatomic molecules

32
Q

What is formed form magnesium reacting with hydrochloric acid?

A

Magnesium chloride

33
Q

What are the colours of Cl2, Br2 and I2 solutions in water?

A

Pale green, orange, brown

34
Q

What is the trend in reactivity down the halogens?

A

Decreases

35
Q

Identify the test and positive results for ammonium ions

A

Add NaOH, warm and test gas/fumes with moist indicator paper. Will turn paper blue (alkaline)

36
Q
A