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3 years ago

EXTREME HURRY!! State the ionization constant expression Ka for lactic acid. Given: pKa = 3.85 and Ka = 1.4*10^-4 mol dm^-3

1 answer:

5 0

Ka expression for any substance:
Ka = [H+] [A-] / [HA]

In this case,
Ka = [H+][C₃H₅O₃-]/[C₃H₆O₃]
1.4 x 10⁻⁴ = [H+] [C₃H₅O₃-] / [C₃H₆O₃]

pKa = -log(Ka)
pH = -log([H+])
The difference between pKa and pH is that pH is the negative logarithm of only the concentration of hydrogen ions, while pKa is the negative logarithm of the ratio of the product of the concentrations of hydrogen ions and concentration of base to the concentration of acid.

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Problem PageQuestion The airbags that protect people in car crashes are inflated by the extremely rapid decomposition of sodium

Shalnov [3]

Answer:

1. 2NaN₃(s) → 2Na(s) + 3N₂(g)

2. 14.5 g NaN₃

Explanation:

The answer is incomplete, as it is missing the required values to solve the problem. An internet search shows me these values for this question. Keep in mind that if your values are different your result will be different as well, but the solving methodology won't change.

" The airbags that protect people in car crashes are inflated by the extremely rapid decomposition of sodium azide, which produces large volumes of nitrogen gas. 1. Write a balanced chemical equation, including physical state symbols, for the decomposition of solid sodium azide (NaN₃) into solid sodium and gaseous dinitrogen. 2. Suppose 71.0 L of dinitrogen gas are produced by this reaction, at a temperature of 16.0 °C and pressure of exactly 1 atm. Calculate the mass of sodium azide that must have reacted. Round your answer to 3 significant digits. "

1. The reaction that takes place is:

2NaN₃(s) → 2Na(s) + 3N₂(g)

2. We use PV=nRT to calculate the moles of N₂ that were produced.

P = 1 atm

V = 71.0 L

n = ?

T = 16.0 °C ⇒ 16.0 + 273.16 = 289.16 K

1 atm * 71.0 L = n * 0.082 atm·L·mol⁻¹·K⁻¹ * 289.16 K

n = 0.334 mol

Now we convert N₂ moles to NaN₃ moles:

0.334 mol N₂ * $\frac{2molNaN_{3}}{3molN_2}$ = 0.223 mol NaN₃

Finally we convert NaN₃ moles to grams, using its molar mass:

0.223 mol NaN₃ * 65 g/mol = 14.5 g NaN₃

6 0

3 years ago

Lab: Magnetic and Electric Fields Step 3: Determine the Polarity of Magnets

Yakvenalex [24]

Answer:

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Explanation:

8 0

3 years ago

Ascorbic acid (H2C6H6O6; H2Asc for this problem), known as vitamin C, is a diprotic acid (Ka1= 1.0x10–5 and Ka2= 5x10–12) found

Igoryamba

Answer:

The concentrations are :

$[HAsc^-]=0.000702 M$

$[Asc^{2-}]=5.92\times 10^{-8} M$

The pH of the solution is 3.15.

Explanation:

$H_2Asc\rightleftharpoons HAs^-+H^+$ $K_{a1}=1.0\times 10^{-5}$

Initial

c 0 0

Equilibrium

c-x x x

$K_{a1}=\frac{[HAs^-][H^+]}{[H_2Asc]}$

$1.0\times 10^{-5}=\frac{x\times x}{(c-x)}$

$1.0\times 10^{-5}=\frac{x^2}{(0.050-x)}$

Solving for x:

x = 0.000702 M

$[HAsc^-]=0.000702 M$

$HAsc^-\rightleftharpoons As^{2-}+H^+$ $K_{a2}=5\times 10^{-12}$

Initially

x 0 0

At equilibrium ;

(x - y) y y

$K_{a2}=\frac{[As^{2-}][H^+]}{[HAsc^-]}$

$5\times 10^{-12}=\frac{y\times y}{(x-y)}$

$5\times 10^{-12}=\frac{y^2}{(x-y)}$

Putting value of x = 0.000702 M

$5\times 10^{-12}=\frac{y^2}{(0.000702 -y)}$

$y=5.92\times 10^{-8} M$

$[Asc^{2-}]=5.92\times 10^{-8} M$

Total concentration of $[H^+]=x+y=0.000702 M+5.92\times 10^{-8} M=7.0206\times 10^{-4} M$

The pH of the solution :

$pH=-\log[H^+]$

$pH=-\log[7.0206\times 10^{-4} M}=3.15$

7 0

2 years ago

Balance the following chemical reaction: _NaOH + _H2SO4 ----->_Na2SO4 +_H20

Dima020 [189]

Answer:

Sodium Hydroxide + Sulfuric Acid = Sodium Sulfate + Water

2NaOH + H2SO4 → Na2SO4 + 2H2O

Explanation:

To balance a chemical equation, enter an equation of a chemical reaction and press the Balance button. The balanced equation will appear above.

Use uppercase for the first character in the element and lowercase for the second character. Examples: Fe, Au, Co, Br, C, O, N, F.

Ionic charges are not yet supported and will be ignored.

Replace immutable groups in compounds to avoid ambiguity. For example, C6H5C2H5 + O2 = C6H5OH + CO2 + H2O will not be balanced, but XC2H5 + O2 = XOH + CO2 + H2O will.

Compound states [like (s) (aq) or (g)] are not required.

You can use parenthesis () or brackets [].

8 0

2 years ago

Use the image above to answer the question: Roger collected four rock samples and wrote a description of how each was formed. Wh

IrinaVladis [17]

Answer:

Explanation:

Cause metamorphic rock is formed by heat pressure overtime

4 0

2 years ago

Read 2 more answers