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Citrus2011 [14]
3 years ago
12

Copper has two isotopes,

Chemistry
1 answer:
Anestetic [448]3 years ago
5 0

Answer:

69.152 % → 63Cu

30.848 % → 65Cu

Explanation:

As you know, the average atomic mass of an element is determined by taking the weighted average of the atomic masses of its naturally occurring isotopes.

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Why does a chemical equation have to be balanced
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The chemical equation needs to be balanced so that it follows the law of conservation of mass.
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The standard entropy change of a reaction has a positive value. This reaction results in: Select the correct answer below: a dec
Ira Lisetskai [31]

Explanation:

The standard entropy change of a reaction has a positive value. This reaction results in an increase in entropy.

Positive entropy means the system has increased its degree of disorderness.

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3 years ago
Match each element to the number of electrons in its valence shell
blondinia [14]

Answer: Be= 2, C =4,  Li = 1 and  B=3

Explanation:

The valence shell can be define as the outermost shell of an atom that contains the valence electrons.

Beryllium (Be), electronic configuration; 1s2 2s2, = 2 electrons in its valence shell.

Carbon (C), electronic configuration; 1s2 2s2 2p2, = 4 electrons in its valence shell.

Lithium (Li), electronic configuration; 1s2 2s1 = 1 electron in its valence shell.

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6 0
3 years ago
I really need help with this I would really appreciate it​
gulaghasi [49]
PV=nRT will give you the answer I think. I haven’t worked with a certain unit in that problem
3 0
3 years ago
The rate constant for a certain reaction is measured at two different temperatures:
Talja [164]

Answer: The activation energy Ea for this reaction is 22689.8 J/mol

Explanation:

According to Arrhenius equation with change in temperature, the formula is as follows.

ln \frac{k_{2}}{k_{1}} = \frac{-E_{a}}{R}[\frac{1}{T_{2}} - \frac{1}{T_{1}}]

k_1 = rate constant at temperature T_1 = 2.3\times 10^8

k_2 = rate constant at temperature T_2 = 4.8\times 10^8

E_a= activation energy = ?

R= gas constant = 8.314 J/kmol

T_1 = temperature = 280.0^0C=(273+280)=553K

T_2 = temperature = 376.0^0C=(273+376)=649K

Putting in the values ::

ln \frac{4.8\times 10^8}{2.3\times 10^8} = \frac{-E_{a}}{8.314}[\frac{1}{649} - \frac{1}{553}]

E_a=22689.8J/mol

The activation energy Ea for this reaction is 22689.8 J/mol

3 0
3 years ago
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