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Law Incorporation [45]

3 years ago

12

What are is unusual because it expands as it freezes. Very few substances have this property the reason liquid water is more den

se than the ice can be best explained by?

1 answer:

tiny-mole [99]3 years ago

8 0

Water expands when frozen into ice and ice is less dense because of the greater volume while holding the same amount of mass

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Can someone help me on this please?

lorasvet [3.4K]

Answer: precambrian

5 0

3 years ago

A certain buffer is made by mixing a weak acid HA and its conjugate base A–. When HA is present at a concentration of 0.5 mM and

MAVERICK [17]

Answer:The ratio of the concentrations of $HA$ and $A^-$ when the buffer has a pH of 7.02 is 0.69

Explanation:

The dissociation constant for formic acid = $K_a=1.8\times 10^{-4}$

Concentration of HA= 0.5 mM

Concentration of $A^-$ = 0.1 mM

pH = 6.16

First we have to calculate the value of $K_a$ .

Using Henderson Hesselbach equation :

$pH=pK_a+\log \frac{[A^-}{[HA]}$

Now put all the given values in this expression, we get:

$6.16=pK_a+\log (\frac{[0.1]}{0.5})$

$pK_a=6.86$

To calculate the ratio of the concentrations of $HA$ and $A^-$ when the buffer has a pH of 7.02.

Using Henderson Hesselbach equation :

$7.02=6.86+\log \frac{[A^-]}{[HA]}$

$7.02=6.86+\log \frac{[A^-]}{[HA]}$

$\frac{[A^-]}{[HA]}=1.44$

$\frac{[HA]}{[A^-]}=0.69$

Thus the ratio of the concentrations of $HA$ and $A^-$ when the buffer has a pH of 7.02 is 0.69

7 0

3 years ago

I’m not sure if the answer is 10^6 or 10^9?

Helga [31]

The answer is 2 enjoy !!

6 0

3 years ago

A biotic or an abiotic resource in the environment that causes population size decrease is

Nadusha1986 [10]

Water! (abiotic)

If water runs out then everything dies! :)

Thanks for the opportunity to answer your question and I hope this help! :)

8 0

3 years ago

Can someone help me with these

prisoha [69]

The answer is B. hope you get it

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3 years ago