Chem Quiz 5 Flashcards

1
Q

pH lower than 7

A

acid

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2
Q

pH greater than 7

A

base

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3
Q

Turns litmus red and phenolphthalien colourless.

A

acid

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4
Q

Turns litmus blue and phenolphthalien pink.

A

base

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5
Q

electrolyte

A

acid and base

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6
Q

what is an electrolyte?

A

A substance that conducts electricity when dissolved ions in solution.

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7
Q

Reacts with metals to form hydrogen gas and a salt.

A

acid

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8
Q

Doesn’t react with non-metals.

A

Base

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9
Q

Reacts together to form water and a salt.

A

acids and bases

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10
Q

What happens in a neutralization reaction when the base contains carbonate, bicarbonate.

A

carbon dioxide is also produced.

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11
Q

sour taste

A

acid

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12
Q

bitter taste

A

base

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13
Q

WHAT SHOULD YOU NEVER DO IN A CHEM LAB?

A

TASTE THE SUBSTANCE!!!!!!!!!!

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14
Q

List the properties of acids.

A

pH lower than 7, turns litmus red, turns phenophthalien colourless, electrolyt, reacts with metals to form Hydrogen and a salt, reacts with bases to form water and a salt, tastes sour.

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15
Q

List the properties of bases.

A

pH greater than7, turns litmus blue, turns phenophthalien pink, electrolyte, don’t usually react with non-metals, reacts with acids to form water and salt, tastes bitter.

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16
Q

What is colourimetry?

A

A technique used to determine the concentration of a colourless compound in a solution.

17
Q

Explain how a spectrophotometer works.

A

A light source is sent through a lens. It reaches a prism and there is a slit that only allows out one colour. The coloured light passes through the sample in cuvette and the detector tells you the absorbance of whatever colour.

18
Q

What does a spectrophotometer find?

A

The absorbance of a certain colour in a coloured substance.

19
Q

What are the 3 ways to measure pH?

A

acid-base indicator, universal indicator, pH meter.

20
Q

What is an acid-base indicator?

A

A chemical substance which changes colour with a change in pH. (litmus, phenolphthalein).

21
Q

What are the pros and cons of acid-base indicators?

A

Pros: inexpensive, easy to use.
Cons: not very precise.

22
Q

What is a universal indicator?

A

A combination of acid base indicators. (wide range pH paper).

23
Q

What are the pros and cons of using universal indicators?

A

Pros: easy to use, more precise than acid-base indicators.
Cons: more expensive than an acid base indicator.

24
Q

What are the pros and cons of using a pH meter?

A

Pros: most precise method of measuring pH.
cons: expensive, having to calibrate them before use.

25
Q

Place the 3 ways of measuring pH in order from most precise to least precise.

A

pH meter, universal indicator, acid-base indicator.

26
Q

According to the acid-base theories of Arrhenius what is an acid?

A

A substance that ionizes in water to produce hydrogen ions H+.

27
Q

Show how HCL ionizes in water.

A

HCL (aq) ->H+(aq) + Cl-(aq)

28
Q

According to the acid-base theories of Arrhenius what is a base?

A

A substance that dissociates in water to produce hydroxide ions OH-.

29
Q

Show how NaOH dissassociates.

A

NaOH(aq)-> Na+(aq) + OH-(aq)

30
Q

List the properties of a strong acid.

A

Ionizes 100% in water, high conductivity, lower pH.

31
Q

Why are strong acids highly conductive?

A

Because they ionize 100%.

32
Q

Why do strong acids have a lower pH?

A

Because they have more hydrogen ions.

33
Q

What are the strong acids that we have to know?

A

HCl, HI, HBr, HNO3, H2SO4, HClO4.

34
Q

Show how acetic acid ionizes in water.

A

CH3COOH(aq) H+(aq) + CH3COO-(aq).

Doesn’t ionize completely.

35
Q

What are the properties of strong bases?

A

Dissociate completely when dissolved in water.

36
Q

Which are the strongest bases?

A

Hydroxides of group 1 and 2 metals.

37
Q

What are the strong bases we have to know?

A

LiOH, NaOH, KOH, RbOH, CsOH, Mg(OH)2, Ca(OH)2, Ba(OH)2, Sr(OH)2.

38
Q

Show how NH3 reacts with H2O.

A

NH3(g) + H2O(l) NH4+(aq) + OH-(aq).

39
Q

What group of metals is always soluble in water?

A

Alkali metals.