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marta [7]
3 years ago
10

Solution A is a 1.00 L buffer solution that is 1.188 M in acetic acid and 1.188 M in sodium acetate. Acetic acid has a pKa of 4.

74. What is the pH change of this solution upon addition of 0.1 mol of HCl? Enter your answer numerically to four decimal places. It will be a negative number.
Chemistry
1 answer:
Tomtit [17]3 years ago
7 0

Answer:

pH change is -0.07

Explanation:

Using H-H equation for acetic acid:

pH = pKa + log [Acetate salt] / [Acetic acid]

Replacing:

pH = 4.74 + log[1.188M] / [1.188M]

pH = 4.74

The HCl reacts with sodium acetate producing acetic acid, thus:

HCl + CH₃COONa → CH₃COOH + NaCl

That means the final moles of sodium acetate are initial moles - moles of HCl and moles of acetic acid are initial moles + moles of HCl.

As the volume of the buffer is 1.0L, initial moles of both substances are 1.188moles. After reaction, the moles are:

sodium acetate: 1.188mol - 0.1mol = 1.088mol

Acetic acid: 1.188mol + 0.1mol = 1.288mol

Using again H-H equation:

pH = 4.74 + log[1.088M] / [1.288M]

pH = 4.67

pH change is: 4.67 - 4.74 = -0.07

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pishuonlain [190]

Answer:

f(x) = 6x²-3

f(x) = 0

6x²-3 = 0

6x² = 3

x² = 3/6

x² = 1/2

x = 1/√2 , -1/√2

Roots of f(x) = 1/√2 , -1/√2

Verification = (i) 6(1/√2)² - 3

= 6(1/2) - 3

= 3-3

= 0

(ii) 6(-1/√2)² - 3

= 6(1/2) - 3

= 3-3

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5 0
3 years ago
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How many iron atoms are in 7.890 g of iron?
zhenek [66]

Answer:

see explanation

Explanation:

#Atoms = (mass/atomic wt) x 6.02 x 10²³

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8 0
2 years ago
Would you expect a Boron (B) atom with atomic mass = 9.999 to be stable?
charle [14.2K]

The balance of forces allows to find the result for the question if the isotope of boron 9.99 una  is stable:

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The stability of atomic nuclei depends on the balance the force is electrostatic repulsion between the protons and the strong interaction of attraction.

One way to achieve this balance is to increase the separation of the protons with uncharged particles between them, the neutral ones, the strong interaction is of the same magnitude for protons and neutrons, therefore the repulsion is decreased and the strong attraction interaction is maintained. .

In the case of Boron, which has 5 protons, the stable structures have more atomistic 10 and 11 una, which is why it has 5 and 6 neutrons each. Therefore each proton has  a neutrons next to it and in the other case a proton at the end has two neutrons, this causes the distance between the protons to increase, decreasing the electrostatic repulsion.

It indicates that we have a Boron nucleus of mass 9.999. The number of protons must remain fixed, therefore there are only 4 neutrons.

Consequently, some of the protons does not have a neutron next to it and can approach the other proton, therefore the electrostatic repulsion increases and the stability of the atom decreases.

In conclusion, using the balance of Forces we can find the result for the question if the isotope of boron 9.99 una is stable:

  • The boron isotope of mass 9.99 amu is unstable because the repulsive force increases.

Learn more about nuclear stability here: brainly.com/question/897383

6 0
3 years ago
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Novosadov [1.4K]

Two common uses for electromagnets are _producing strong magnetic fields_& __electrical switches_.

Explanation:

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An electromagnet switch can also be applied in the switching on and off of a larger current. These are called relay switches. When the smaller current is turn on, it magnetizes a ferromagnetic material. The magnet then attracts another metal that is attached to a contact arm of a switch. The attraction results in the closing of a switch  of a larger current. When the smaller current is switched off, the loss of magnetism causes the metal with the contact arm to open the larger switch.

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6 0
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Inga [223]

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So the identity of the species: ^{136}Ba^{-}

3 0
3 years ago
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