An element has an atomic number of 78. the number of protons and electrons in a neutral atom of the element would be _____.

Chemistry

1 answer:

Maurinko [17]4 years ago

5 0

78 and 78. An atom of the element has 78 electrons and 78 protons.

The atomic number is 78, so the atom has 78 protons (+).

If the atom is neutral, it must contain 78 electrons (-).

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Please help, I'm confused and it's due very soon!

ryzh [129]

Answer:

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Explanation:

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3 years ago

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abruzzese [7]

Explanation:

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3 years ago

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klio [65]

Since the forward reaction is endothermic (heat is consumed in the reaction) that means that the enthalpy change for the forward reaction is a positive value.
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3 years ago

Compounds pure substances made of two or more types of _____ and are _____ _______

melomori [17]

Answer: chemical substance

Explanation:

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3 years ago

I need help on both a and b of question 1

marishachu [46]

Answer:

(a) -0.00017 M/s;

(b) 0.00034 M/s

Explanation:

(a) Rate of a reaction is defined as change in molarity in a unit time, that is:

$r = \frac{\Delta c}{\Delta t}$

Given the following reaction:

$2 N_2O_5 (g)\rightleftharpoons 4 NO_2 (g) + O_2 (g)$

We may write the rate expression in terms of reactants firstly. Since reactants are decreasing in molarity, we're adding a negative sign. Similarly, if we wish to look at the overall reaction rate, we need to divide by stoichiometric coefficients:

$r = -\frac{\Delta [N_2O_5]}{2 \Delta t}$