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3 years ago

I need help with this pleae

Chemistry

1 answer:

pantera1 [17]3 years ago

3 0

Depositional landforms are the visible evidence of processes that have deposited sediments or rocks after they were transported by flowing ice or water, wind or gravity. Examples include beaches, deltas, glacial moraines, sand dunes and salt domes

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Phosphoric acid is a triprotic acid ( K a1 = 6.9 × 10 − 3 Ka1=6.9×10−3, K a2 = 6.2 × 10 − 8 Ka2=6.2×10−8, and K a3 = 4.8 × 10 −

irina1246 [14]

Answer: To calculate the pH of the buffer composed of $H_2PO_4^-\text{ and }HPO_4^{-2}$ , we use the $K_a2$

Explanation:

Phosphoric acid is a triprotic acid and it will undergo three dissociation reaction each having their respective dissociation constants.

The chemical equation for the first dissociation reaction follows:

$H_3PO_4\rightleftharpoons H_2PO_4^-+H^+;K_a1=6.9\times 10^{-3}$

The chemical equation for the second dissociation reaction follows:

$H_2PO_4^-\rightleftharpoons HPO_4^{2-}+H^+;K_a2=6.2\times 10^{-8}$

The chemical equation for the third dissociation reaction follows:

$HPO_4^{2-}\rightleftharpoons PO_4^{3-}+H^+;K_a3=4.8\times 10^{-13}$

To form a buffer composed of $H_2PO_4^-\text{ and }HPO_4^{-2}$ , we use the $K_a$ of second dissociation process

To calculate the $pK_a$ , we use the equation:

$pK_a=-\log (K_a)\\\\pK_a=-\log(6.2\times 10^{-8})\\\\pK_a=7.21$

To calculate the pH of buffer, we use the equation given by Henderson Hasselbalch:

$pH=pK_a2+\log(\frac{[\text{conjugate base}]}{[\text{weak acid}]})$

$pH=pK_a2+\log(\frac{[HPO_4^{2-}]}{[H_2PO_4^-]})$

We are given:

$pK_a2$ = negative logarithm of second acid dissociation constant of phosphoric acid = 7.21

$[HPO_4^{2-}]$ = concentration of conjugate base

$[H_2PO_4^{-}]$ = concentration of weak acid

Hence, to calculate the pH of the buffer composed of $H_2PO_4^-\text{ and }HPO_4^{-2}$ , we use the $K_a2$

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4 years ago

N2 + 3H2 → 2NH3 △H = -92 kJ / mol

Tpy6a [65]

Explanation:

(e)the heat is absorbed into the reaction .

3 0

1 year ago

What is an element in science

s2008m [1.1K]

An element is a part or aspect of something abstract, especially one that is essential or characteristic. I hope this helps you good luck :)

5 0

3 years ago

Read 2 more answers

What is the only element in group 1 on the periodic table that forms covalent bonds?

Citrus2011 [14]

I believe it is Hydrogen?

8 0

3 years ago

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How many moles are in 1.22 * 10^20 atoms of Si

mezya [45]

Answer:

2.03 × 10⁻⁴ moles

Explanation:

To convert atoms to moles, use Avogadro's number (6.022 × 10²³).

(1.22 × 10²⁰ atoms)/(6.022 × 10²³ atoms/mol) = 2.03 × 10⁻⁴ mol

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3 years ago