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sweet-ann [11.9K]
3 years ago
5

Which equation obeys the law of conservation of mass?

Chemistry
2 answers:
Gala2k [10]3 years ago
8 0

Explanation:

According to law of conservation of mass, total mass of reactants will be equal to the total mass of products.

For example, HCl + NaOH \rightarrow NaCl + H_{2}O

Therefore, mass of reactant molecules will be as follows.

Mass of HCl is 36.46v g/mol

Mass of NaOH is 39.99 g/mol

Total mass of reactants is (36.46 + 39.99) g/mol = 76.45 g/mol

Mass of product molecules will be as follows.

Mass of NaCl is 58.44 g/mol

Mass of H_{2}O is 18.01 g/mol

Total mass of products is (58.44 + 18.01) g/mol = 76.45 g/mol

Thus, we can conclude that any equation which represents total mass of reactants equal to the total mass of products is actually obeying the law of conservation of mass.

elena55 [62]3 years ago
3 0
4Fe + 3O2 → 2Fe2O3, hope this helps man!
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Where is most of the mass of an atom? •
yaroslaw [1]
B. inside the nucleus
6 0
3 years ago
How many grams do 6.534e+24 molecules of phosphoric acid weigh?
fredd [130]

Answer:

1,063 grams H₃PO₄

Explanation:

To find the mass of phosphoric acid (H₃PO₄), you should (1) convert molecules to moles (via Avogadro's number) and then (2) convert moles to grams (via molar mass from periodic table).

Molar Mass (H₃PO₄): 3(1.008 g/mol) + 30.974 g/mol + 4(15.998 g/mol)

Molar Mas (H₃PO₄): 97.99 g/mol

6.534 x 10²⁴ molecules H₃PO₄                       1 mole                         97.99 g
---------------------------------------------  x  -------------------------------------  x  --------------
                                                            6.022 x 10²³ molecules          1 mole

= 1,063 grams H₃PO₄

3 0
1 year ago
Choose the best statement of the octet rule from those listed below atoms lose 8 electrons to become valent atoms lose 8 electro
Mnenie [13.5K]

Answer:

atoms tend to react in order to gain 8 valence electrons

Explanation:

The octet rule describes the tendency of atoms of elements to react in order to have eight electrons in their valence shell. This is because having eight valence electrons confers stability to the atoms of these elements in the compounds they form.

The octet rule only does not apply to the transition elements or the inner transition elements as only the s and p electrons are involved. the electronic configuration in atoms having an octet is s²p⁶.

For example, sodium atom has one valence electron in its valence shell but a complete octet in the inner shell; it will react with chlorine atom which has seven valence electrons to form a stable compound, sodium chloride by donating its one valence electron in order to have an octet. Similarly, the chlorine atom will then have an octet by accepting the one electron from sodium atom.

7 0
3 years ago
Free-energy change, ΔG∘, is related to cell potential, E∘, by the equationΔG∘=−nFE∘where n is the number of moles of electrons t
mart [117]

Answer:

a)\Delta G=372490 J

b)\Delta G=-568614 J

Explanation:

a) The reaction:

Mg(s) +Fe^{2+}(aq) \longrightarrow Mg^{2+}(aq) + Fe(s)

The free-energy expression:

\Delta G=-n*F*E

E=E_{red}-E_{ox]

The element wich is reduced is the Fe and the one that oxidates is the Mg:

-0.44V=E_{red}-(-2.37V)=1.93V

The electrons transfered (n) in this reaction are 2, so:

\Delta G=-2mol*96500 C/mol * 1.93 V

\Delta G=-372490 J

b) If you have values of enthalpy and enthropy you can calculate the free-energy by:

\Delta G=\Delta H - T* \Delta S

with T in Kelvin

\Delta G=-675 kJ*\frac{1000J}{kJ} - 298K*-357 J/K

\Delta G=-568614 J

7 0
2 years ago
If you start with 0.020 g of Mg, how many moles of H2 will you make if the reaction is complete?
irina [24]

If one starts with 0.020 g of Mg, 0.0008 moles of H2 would be made if the reaction is complete.

Going by the balanced equation of reaction in the image, 1 mole of Mg will produce 1 mole of H2 in a complete reaction.

If 0.020 g of Mg is started with:

mole of Mg = mass/molar mass

                        = 0.020/24.3

                            = 0.0008 moles

Since the mole of Mg to H2 is 1:1, thus, 0.0008 moles of H2 will also be made from the reaction.

More on stoichiometry can be found here: brainly.com/question/9743981

6 0
2 years ago
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