How do you find the atomic mass mass number of an atom?

1 answer:

fomenos3 years ago

7 0

To calculate the atomic mass<span> of a single </span>atom<span>, add up the </span>mass<span> of protons and neutrons.

So, your answer would be A) add the number of protons and neutrons</span>

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If 2.0 g of copper(II) chloride react with excess sodium nitrate, what mass of sodium chloride is formed in this double replacem

cluponka [151]

Taking into account the reaction stoichiometry, 1.729 grams of NaCl is formed.

<h3>Reaction stoichiometry</h3>

In first place, the balanced reaction is:

CuCl₂ + 2 NaNO₃ → Cu(NO₃)₂ + 2 NaCl

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

CuCl₂: 1 mole
NaNO₃: 2 moles
Cu(NO₃)₂ : 1 mole
NaCl: 2 moles

The molar mass of the compounds is:

CuCl₂: 134.44 g/mole
NaNO₃: 85 g/mole
Cu(NO₃)₂ : 187.54 g/mole
NaCl: 58.45 g/mole

Then, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:

CuCl₂: 1 mole ×134.44 g/mole= 134.44 grams
NaNO₃: 2 moles ×85 g/mole= 170 grams
Cu(NO₃)₂ : 1 mole ×187.54 g/mole= 187.54 grams
NaCl: 2 moles ×58.45 g/mole= 116.9 grams

<h3>Mass of NaCl formed</h3>

The following rule of three can be applied: If by stoichiometry of the reaction 134.44 grams of CuCl₂ form 116.9 grams of NaCl, 2 grams of CuCl₂ form how much mass of NaCl?

$mass of NaCl=\frac{2 grams of CuCl_{2}x116.9 grams of NaCl }{134.44grams of CuCl_{2}}$

<u><em>mass of NaCl= 1.739 grams</em></u>

Finally, 1.729 grams of NaCl is formed.

Learn more about the reaction stoichiometry:

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6 0

2 years ago

B. 10% is the correct answer

GarryVolchara [31]

No the right answer is c

5 0

3 years ago

Read 2 more answers

Why methylene blue is blue

bixtya [17]

Methylene blue indicates the presence of oxidizing agents because it is oxidized itself by these compounds. When electrons are stripped from methylene blue, the resulting molecule imparts a blue color to the solution--giving a clear sign of a chemical change.

7 0

3 years ago

Ammonia can be produced via the chemicalreaction

otez555 [7]

Answer:

3)The reaction is not at equilibrium and willproceed to the right.

Explanation:

The reaction quotient of an equilibrium reaction measures relative amounts of the products and the reactants present during the course of the reaction at particular point in the time.

It is the ratio of the concentration of the products and the reactants each raised to their stoichiometric coefficients. The concentration of the liquid and the gaseous species does not change and thus is not written in the expression.

Q < Kc , reaction will proceed in forward direction.

Q > Kc , reaction will proceed in backward direction.

Q = Kc , reaction at equilibrium.

Given that:

Q = $3.56\times 10^{-4}$