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2 years ago

at a particulat temperature, a smaple of pure water has a Kw of 7.7x10-14. what is the hydroxide concentration of this sample

Chemistry

1 answer:

ycow [4]2 years ago

4 0

Answer: The hydroxide concentration of this sample is $3.85\times 10^{-7}$

Explanation:

When an expression is formed by taking the product of concentration of ions raised to the power of their stoichiometric coefficients in the solution of a salt is known as ionic product.

The ionic product for water is written as:

$K_w=[H^+]\times [OH^-]$

$7.7\times 10^{-14}=[H^+]\times [OH^-]$

As $[H^+]=[OH^-]$

$2[OH^-]=7.7\times 10^{-14}$

$[OH^-]=3.85\times 10^{-7}$

Thus hydroxide concentration of this sample is $3.85\times 10^{-7}$

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An ethylene glycol solution contains 21.4 g of ethylene glycol (C2H6O2) in 97.6 mL of water. (Assume a density of 1.00 g/mL for

8090 [49]

Answer: The freezing point and boiling point of the solution are $-6.6^0C$ and $101.8^0C$ respectively.

Explanation:

Depression in freezing point:

$T_f^0-T^f=i\times k_f\times \frac{w_2\times 1000}{M_2\times w_1}$

where,

$T_f$ = freezing point of solution = ?

$T^o_f$ = freezing point of water = $0^0C$

$k_f$ = freezing point constant of water = $1.86^0C/m$

i = vant hoff factor = 1 ( for non electrolytes)

m = molality

$w_2$ = mass of solute (ethylene glycol) = 21.4 g

$w_1$ = mass of solvent (water) = $density\times volume=1.00g/ml\times 97.6ml=97.6g$

$M_2$ = molar mass of solute (ethylene glycol) = 62g/mol

Now put all the given values in the above formula, we get:

$(0-T_f)^0C=1\times (1.86^0C/m)\times \frac{(21.4g)\times 1000}{97.6g\times (62g/mol)}$

$T_f=-6.6^0C$

Therefore,the freezing point of the solution is $-6.6^0C$

Elevation in boiling point :

$T_b-T^b^0=i\times k_b\times \frac{w_2\times 1000}{M_2\times w_1}$

where,

$T_b$ = boiling point of solution = ?

$T^o_b$ = boiling point of water = $100^0C$

$k_b$ = boiling point constant of water = $0.52^0C/m$

i = vant hoff factor = 1 ( for non electrolytes)

m = molality

$w_2$ = mass of solute (ethylene glycol) = 21.4 g

$w_1$ = mass of solvent (water) = $density\times volume=1.00g/ml\times 97.6ml=97.6g$

$M_2$ = molar mass of solute (ethylene glycol) = 62g/mol

Now put all the given values in the above formula, we get:

$(T_b-100)^0C=1\times (0.52^0C/m)\times \frac{(21.4g)\times 1000}{97.6g\times (62g/mol)}$

$T_b=101.8^0C$

Thus the boiling point of the solution is $101.8^0C$

4 0

3 years ago

Please help with this

dlinn [17]

Answer:

A sample of a gas (5.0 mol) at 1.0 atm is expanded at constant temperature from 10 L to 15 L. The final pressure is 0.67 atm.

Step by Step Explanation?

Boyle's law states that in constant temperature the variation volume of gas is inversely proportional to the applied pressure.

The formula is,

P₁ x V₁ = P₂ × V₂

Where,

P₁ is initial pressure = 1 atm

P2 is final pressure = ? (Not Known)

V₁ is initial volume = 10 L

V₂ is final volume = 15 L

Now put the values in the formula,

\begin{gathered}\rm 1\times 10 = P_2\times 15\\\\\rm P_2 = \frac{10}{15\\} \\\\\rm P_2 = 0.67\end{gathered]

Therefore, the answer is 0.67 atm.

5 0

1 year ago

Read 2 more answers

Approximately how long does it take for the moon's phases to change from a NEW moon to a FULL moon?

stiks02 [169]

Answer:

4 weeks

Explanation:

It takes 4 weeks for the cyclle to be happening again

8 0

2 years ago

What is a net ionic equation?

jolli1 [7]

Answer:

I think it will option D hope it helps

7 0

2 years ago

What mineral has the least hardness according to the scale?

kenny6666 [7]

The softest mineral in the Mohs Hardness Scale is talc.
Talc is often used in baby powder and corn starch, among other things. Talc cleaves into thin sheets, and it is held together only by van de Waals bonds, which allows these sheets to slip past each other. This gives the mineral its softness and it is often valued as a high-temperature lubricant.

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2 years ago