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4 years ago

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A chemist titrates 150.0 mL of a 0.2653 M carbonic acid (H2CO3) solution with 0.2196 M NaOH solution at 25 °C. Calculate the pH

at equivalence. The pKa of carbonic acid is 3.60

1 answer:

xxTIMURxx [149]4 years ago

6 0

Answer:

9.3

Explanation:

This is long and complicated so get ready

We are going to use the conjugate base of carbonic acid with water to make carbonic acid and OH- (Na is simply a spectator ion and is irrelavent here)

Let the conjugate base be A- and Carbonic acid be HA

A- + H20 ⇄ HA + OH-

To find the concentration of A- we must find the concentration of the reactants given. We know this will be equal because it is a strong base and all of it disassociates.

to get moles of acid we take the concentration and multiply by liters to cancel

.2653 x .150 = .039795 mol HA

Because it is at equivalence point we know the moles will be equal. We are given the concentration so we only have to solve for liters

We plug it into the equation and found: .181 L

Now use moles and combined volums to fins concentrarion which is .120 M

Now plug that use the Ka converted to Kb to find the cincentrations of HA and OH-

Ka is (10^-3.60) = 2.4E-4

Kb x Ka is 10^-14

Kb = 3.98E-11

Now we know Kb = [HA] [OH] / [A-]

Solve for this through algebra by using x for the values you dont know

youll find x^2 = 3.3E-10

X = 1.8 E -5

this is the OH- concentration

-log [oh] = pOH

pOH = 4.73

We know 14-pOH = ph so pH= 9.3

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Answer:

Explanation:

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Starting with 2.50 mol of N2 gas (assumed to be ideal) in a cylinder at 1.00 atm and 20.0C, a chemist first heats the gas at con

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Answer:

a) $T_b=590.775k$

b) $W_t=1.08*10^4J$

d) $Q=3.778*10^4J$

d) $\triangle V=4.058*10^4J$

Explanation:

From the question we are told that:

Moles of N2 $n=2.50$

Atmospheric pressure $P=100atm$

Temperature $t=20 \textdegree C$

$t = 20+273$

$t = 293k$

Initial heat $Q=1.36 * 10^4 J$

a)

Generally the equation for change in temperature is mathematically given by

$\triangle T=\frac{Q}{N*C_v}$

Where

$C_v=Heat\ Capacity \approx 20.76 J/mol/K$

$T_b-T_a=\frac{1.36 * 10^4 J}{2.5*20.76 }$

$T_b-293k=297.775$

$T_b=590.775k$

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Generally the equation for ideal gas is mathematically given by

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For v double

$T_c=2*590.775k$

$T_c=1181.55k$

Therefore

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$Wbc=(2.20)(8.314)(1181_590.778)$

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$W_t=1.08*10^4J$

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Generally the equation for amount of heat added is mathematically given by

$Q=nC_p\triangle T$

$Q=2.20*2907*(1181.55-590.775)\\$

$Q=3.778*10^4J$

d)

Generally the equation for change in internal energy of the gas is mathematically given by

$\triangle V=nC_v \triangle T$

$\triangle V=2.20*20.76*(1181.55-293)k$

$\triangle V=4.058*10^4J$

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3 years ago

Which statement is correct regarding the reaction below? 3A + 2B yields C + 2D The rate of formation of D is twice the rate of d

Vedmedyk [2.9K]

Answer:

The correct statements are:

The rate of disappearance of B is twice the rate of appearance of C.

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Rate of the reaction:

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The rate of disappearance of B is twice the rate of appearance of C.

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The nuclear number or proton number (image Z) of a synthetic component is the quantity of protons found in the core of a particle. It is indistinguishable from the charge number of the core. The nuclear number particularly distinguishes a compound component. In an uncharged iota, the nuclear number is likewise equivalent to the quantity of electrons.

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The nuclear number (otherwise called the proton number) is the quantity of protons found in the core of an iota. It is customarily spoken to by the image Z. The nuclear number exceptionally distinguishes a substance component. In a particle of impartial charge nuclear number is equivalent to the quantity of electrons.

Meaning of subshell:

A subshell is a subdivision of electron shells isolated by electron orbitals. Subshells are marked s, p, d, and f in an electron design.

Subject: chemistry

Level: High School

Keywords: atomic number, The elemenents of the intermittent table arranged by atomic mass, atomic number speak to, Meaning of subshell.

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3 years ago

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which of the following is a balanced chemical equation for the reaction of magnesium with nitrogen gas to form magnesium nitride

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So the unbalanced equation would be Mg + N^2 --> Mg^3N^2

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