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3 years ago

What happens during chemical reactions?

Chemistry

2 answers:

san4es73 [151]3 years ago

7 0

Answer:

I'm pretty sure it is A but, sorry if I'm wrong!!!

stiv31 [10]3 years ago

4 0

Answer:

Energy is given off or absorbed.

Explanation:

A P E X

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which of the following charecteristics will not help u tell whether two solids are the same or are diferent substances?

Sladkaya [172]

Answer:

D. Melting point

Explanation:

A. Color

B. Hardness

C. Shape

D. Melting point

4 0

2 years ago

A monoprotic weak acid, HA , dissociates in water according to the reaction:

Ratling [72]

<u>Answer:</u> The $pKa$ of the acid is 6.09

<u>Explanation:</u>

For the given chemical reaction:

$HA(aq.)\rightleftharpoons H^+(aq.)+A^-(aq.)$

The expression of equilibrium constant [tex[(K_a)[/tex] for the above equation follows:

$K_a=\frac{[H^+][A^-]}{[HA]}$

We are given:

$[HA]_{eq}=0.200M$

$[H^+]_{eq}=4.00\times 10^{-4}M$

$[A^-]_{eq}=4.00\times 10^{-4}M$

Putting values in above expression, we get:

$K_a=\frac{(4.00\times 10^{-4})\times (4.00\times 10^{-4}}{0.200}\\\\K_a=8.0\times 10^{-7}0$

p-function is defined as the negative logarithm of any concentration.

$pKa=-\log(K_a)$

So,

$pKa=-\log(8.0\times 10^{-7})\\\\pKa=6.09$

Hence, the $pKa$ of the acid is 6.09

7 0

4 years ago

Which sample of matter can be separated into different substances by physical means

SpyIntel [72]

Answer:

a heterogeneous mixture

Explanation:

an example would be sand and water because it can be filtered which is a physical mean of separation.

5 0

3 years ago

Read 2 more answers

Match the academic requirements with the careers . Cosmetologist

inessss [21]

Answer:

Technical program - cosmetologist

5 0

4 years ago

PV = nRT. If P = 1 atm, V = 5.0 liter, R = 0.0821 L.atm/mol.K, and T = 293 K; what is the value of n?

Leya [2.2K]

Answer:

n = 0.207 mole

Explanation:

We have,

P = 1 atm

V = 5 liter

R = 0.0821 L.atm/mol.K

T = 293 K

We need to find the value of n. The relation is as follows :

PV = nRT

Solving for n,

$n=\dfrac{PV}{RT}\\\\n=\dfrac{1\times 5}{0.0821 \times 293}\\\\n=0.207\ \text{mol}$

So, the value of n is 0.207 mol.

6 0

3 years ago