pH Flashcards

1
Q

what does pH measure?

A

pH is a measure of the hydrogen ion concentration of a solution.

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2
Q

What would you define pH solution that is less than 7?

A

If the pH of a solution is less than 7 then the solution is acidic.

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3
Q

What would you define pH solution that is greater than 7?

A

If the pH solution is greater than 7 then the solution is alkaline

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4
Q

What would you define a solution that is equal to 7?

A

For pH=7 then the solution is neutral.

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5
Q

What does dissociation of water mean?

A

In pure water a small number of molecules split up (dissociate) into hydrogen ions, H+, and hydroxide ions, OH-. The reactions are reversible: they can go forwards or back.

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6
Q

What is the pH of the dissociation of water reaction in pure water and why?

A

In pure water, there is an equal concentration of hydrogen ions and hydroxide ions so the pH is equal to 7.

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7
Q

In what solution is the concentration of hydrogen ions greater than the concentration of hydroxide ions?

A

In acidic solutions, the concentration of hydrogen ions is greater than the concentration of hydroxide ions.

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8
Q

In which solution is the concentration of hydroxide ions greater than the concentration of hydrogen ion?

A

In alkaline solutions, the concentration of hydroxide ions is greater than the concentration of hydrogen ions.

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9
Q

What do “[ ]” represent?

A

Concentration of

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10
Q

What is the test for hydrogen?

A

The test for hydrogen is that it goes “pop” with a lighted splint.

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11
Q

Explain three things that happen when an acidic solution is diluted with water.

A

The concentration of hydrogen ions decreases
The solution becomes less acidic
The pH rises towards 7

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12
Q

Explain three things that happen when an alkaline solution is diluted with water.

A

The concentration of hydroxide ions decrease
The solution becomes less alkaline
The pH decreases towards 7

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13
Q

How is the pH affected when an acid or alkali is diluted by a factor of 10?

A

When an acid or alkali is diluted by a factor of 10 the pH changes by 1.

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14
Q

How are acidic solutions produced?

A

Soluble non-metal oxides dissolve in water producing acidic solutions. This means that soluble non-metal oxides produce hydrogen ions, H+, in solution.

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15
Q

What are the formula and ionic formulae for hydrochloric acid?

A

HCL and H+CL-

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16
Q

What are the formula and ionic formulae for sulfuric acid?

A

H2SO4 or (H+)2SO42-

17
Q

What are the formula and ionic formulae for Nitric acid?

A

HNO3 and H+NO3-

18
Q

How are alkaline solutions formed?

A

Soluble metal oxides dissolve in water to form alkaline solutions. This means that soluble metal oxides produce hydroxide ions, OH-, in solution.

19
Q

What is the word equation for the formation of metal hydroxides?

A

Soluble metal oxide+water–>metal hydroxide.

20
Q

How do we figure out if a metal oxide is soluble?

A

To find out if a metal oxide is soluble, check the solubility table on page 8 of the data booklet.

21
Q

Do all metal oxides dissolve in water and how can we check this?

A

Not all Metal oxides dissolve in water. You can use the solubility table in the data booklet to check this.

22
Q

What can affect the pH of the water?

A

Only the soluble metal oxides affect the pH of the water. They form alkaline solutions so the universal indicator turns blue.

23
Q

Name two metal oxides that are insoluble in water so do not form alkaline solutions.

A

Metal oxides like copper oxide and iron oxide are insoluble in water so do not form alkaline solutions.

24
Q

What are the formula and ionic formulae for Potassium hydroxide?

A

KOH or K+OH-

25
Q

What are the formula and ionic formulae for sodium hydroxide?

A

NaOH or Na+OH-

26
Q

What are the formula and ionic formulae for Lithium hydroxide?

A

LiOH or Li+OH-

27
Q

What are the formula and ionic formulae for calcium hydroxide?

A

Ca(OH)2 or Ca2+(OH-)2

28
Q

What are bases?

A

Metal oxides, Metal hydroxides, Metal carbonates and ammonia are called bases. Bases are substances that can neutralise acids.

29
Q

What do bases that dissolve in water form?

A

Bases that dissolve in water form alkaline solutions.

30
Q

Why does pure water have low conductivity?

A

Pure water contains a very low concentration of hydrogen ions and hydroxide ions, giving it a very low conductivity.