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gulaghasi [49]
3 years ago
6

Which of the following aqueous solutions are good buffer systems? . 0.32 M calcium chloride + 0.27 M sodium chloride 0.35 M ammo

nia + 0.36 M calcium hydroxide 0.19 M barium hydroxide + 0.28 M barium chloride 0.12 M hydrofluoric acid + 0.17 M potassium fluoride 0.20 M hydrobromic acid + 0.22 M sodium bromide
Chemistry
1 answer:
irga5000 [103]3 years ago
7 0

Answer:

0.12 M hydrofluoric acid + 0.17 M potassium fluoride

Explanation:

To make a buffer, you must to have an aqueous mixture of a weak acid and its conjugate base or vice versa.

Knowing that:

0.32 M calcium chloride + 0.27 M sodium chloride: <em>is not a good buffer system </em>because CaCl₂ and NaCl are both salts.

0.35 M ammonia + 0.36 M calcium hydroxide <em>is not a good buffer system </em>because ammonia is a weak base but calcium hydroxide is a strong base

0.19 M barium hydroxide + 0.28 M barium chloride <em>is not a good buffer system </em>because Ba(OH)₂ is a strong base.

0.12 M hydrofluoric acid + 0.17 M potassium fluoride <em>is a good buffer system </em>because HF is a weak acid and KF (F⁻ in aqueous medium), is its conjugate base

0.20 M hydrobromic acid + 0.22 M sodium bromide <em>is not a good buffer system </em>because HBr is a strong acid.

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Lady_Fox [76]

Answer:

In case of plants surface tension help to support the transpiration pull.

Explanation:

Surface tension is a force that hold the molecules in the surface to minimize the surface area.

   During evaporation of excess amount of water from the stomata of leaves of plants by transpiration a surface tension is generated.

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3 0
3 years ago
There are three factors in which natural selection occurs. Select one statement from the list below that is a true statement abo
azamat

Answer: There is no list in your question. But the three factors in which natural selection occurs are:

1. A struggle for existence,

2. Variation and

3. Inheritance

Explanation:

Darwin’s theory of natural selection is the way in which organisms change overtime.

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1. A struggle for existence,

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8 0
3 years ago
If 60. liters of hydrogen gas at 546 K is cooled to 273 K at constant pressure, the new volume of the gas would be
Korvikt [17]

Answer:30 L

Explanation:

Initial Volume

=

V

1

=

60

l

i

t

e

r

Initial Temperature

=

T

1

=

546

K

Final Temperature

=

T

2

=

273

K

Final Vloume

=

V

2

=

?

?

Sol:-

Since the pressure is constant and the question is asking about temperature and volume, i.e,

V

1

T

1

=

V

2

T

2

⇒

V

2

=

V

1

⋅

T

2

T

1

=

60

⋅

273

546

=

60

2

=

30

l

i

t

e

r

⇒

V

2

=

30

l

i

t

e

r

Hence the new volume of the gas is

30

l

i

t

e

r

6 0
3 years ago
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Semmy [17]

Answer:

89.1 N

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W = m gm = 55.0 x 1.62 = 89.1 N

5 0
3 years ago
How many atoms are in 4 moles of oxygen?
Paha777 [63]

Answer:

There are 6.022 × 10 23 O atoms in a mole of O atoms. There are 6.022 × 10 23 O 2 molecules in a mole of . Since you have 2 oxygen atoms in one molecule, there are 2 × 6.022 × 10 23 O atoms in a mole of . A 'mole' is not short for a 'molecule

Explanation:

5 0
3 years ago
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