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2 years ago

Can you please help solve and explain the steps for the calculation?

Chemistry

1 answer:

Nimfa-mama [501]2 years ago

8 0

Answer:

The hydrogen ion concentration in a solution, [H+], in mol L-1, can be calculated if the pH of the solution is known.

pH is defined as the negative logarithm (to base 10) of the hydrogen ion concentration in mol L-1 pH = -log10[H+] ...

[H+] in mol L-1 can be calculated using the equation (formula): [H+] = 10-pH

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Which of the following electron configurations gives the correct arrangement of the four valence electrons of the carbon atom in

Juliette [100K]

Answer:

D) $2s^12p^3$

Explanation:

Carbon.

The electronic configuration is -

$1s^22s^22p^2$

Thus, 2s orbital is fully filled and p orbital can singly filled 3 electrons. Thus, Carbon has 2 singly occupied orbitals.

But in methane, $CH_4$ it forms 4 bonds. So, 1 electron each from 2s orbital jumps to the next orbital in the p subshell.

Thus, the configuration is:-

$1s^22s^22p^2$

Thus, the valence electron configuration is:-

$2s^12p^3$

7 0

2 years ago

Near the equator, the sun heats the surface strongly, causing warm air to rise steadily. This creates the _________________, an

kenny6666 [7]

Doldrums, low is the correct answer.

8 0

2 years ago

Calculate the ph of a 0.20 m solution of kcn at 25.0 ∘c. express the ph numerically using two decimal places

storchak [24]

The pH of the solution is basically the negative logarithm of the concentration of hydrogen ions or H+. In equation form, pH = -log[H+]. It could also be in terms of the concentration of hydroxide ions or OH- as pOH, where pOH = -log[OH-]. The sum of pH and pOH is 14. These are the important equations to know when it comes to equilibrium pH problems.

KCN is a basic salt coming from the reaction of a weak acid, HCN, and a strong base, KOH. In the hydrolysis of KCN, only the strong conjugate base (SCB) is involved. Since HCN is the weak acid, the SCB is CN-. The reaction would be

CN- + H2O ⇔ HCN + OH-

The important data is the equilibrium constant of acidity of the weak acid. Ka for HCN is 6.2×10^-10. Then, let's do the ICE(Initial-Change-Equilibrium) analysis.

CN- + H2O ⇔ HCN + OH-

I 0.2 m ∞ 0 0
C -x ∞ +x +x
-----------------------------------------------------------
E 0.2-x +x +x

The value x denotes the number of moles CN- reacted. There is no value for H2O because the solution is dilute such that H2O>>>CN-. Then, we apply the ratio:

$K_{H} = \frac{ K_{W} }{ K_{A} } = \frac{[HCN][OH-]}{[CN-]}$

where K,H is the equilibrium constant of hydrolysis and Kw is equilibrium constant for water solvation which is equal to 1×10^-14. Therefore,

$K_{H} = \frac{ 1x10^-14}{ 6.2x10^-10 } = \frac{[X][X]}{[0.2-X]}$

x = 0.001788 m
Since the value of OH- is also x, then OH-=0.001788 m. Consequently,

pOH = -log(0.001788) = 2.75
pH = 14 - pOH = 14 - 2.75
pH = 11.25

4 0

3 years ago

Read 2 more answers

While you are using a battery, the cell reaction is going a) forward, b) backward, c) at equilibrium, d) TEXASIN all possible

polet [3.4K]

Answer:Cell reaction is going forward.

Explanation:

For any chemical reaction to be spontaneous or to move in forward direction the ΔG ,the Gibbs free energy must be negative.

The cell potential of a battery is positive for a spontaneous reaction, so for a battery to give output its cell potential must be positive.

Thermodynamics and electro-chemistry are related in the following manner:

ΔG=-nFE

n=number of electrons involved

F=Faradays constant

E=cell pottential of battery

so from the above equation ΔG would only be negative when E cell that is the cell potential is positive.

For a battery which is being used its cell potential is positive and hence the ΔG would be negative. So the cell reaction occurring would be in forward direction as ΔG is negative.

when the cell potential Ecell is 0 then ΔG is also zero then the reaction occurring in battery would be at equilibrium.

When the cell potential Ecell is - then ΔG is positive and the reaction would be occurring backwards.

3 0

2 years ago

The mass of a 6.0 mL sample of kerosene is 4.92. The density of kerosene is

weqwewe [10]

4.92 grams / 6 mL = .82 grams / mL

<span>(A) 0.82 g/mL</span>

3 0

2 years ago