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3 years ago

1. An example of a polyatomic ion is:a) SO²-4b) Ca?c) O2d) NaCl

Chemistry

1 answer:

zlopas [31]3 years ago

8 0

Answer:

A is the answer. Ca(calcium) is an element, O2 is a diatomic element, and NaCl is a compound composed of Na(sodium) and Cl(chlorine)

Explanation:

hopefully that helps!!!

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What is the symbol for the carbon isotope with seven neutrons?

Tresset [83]

Carbon -13 has 7 neutrons and carbon -12 has six neutrons. Carbon -12 is the most common isotope of Carbon. Carbon -14 is radioactive and vary rare. The symbols for the isotopes of Carbon atoms shown here indicate they each have six protons but mass numbers of 14, 13, and 12. Hope this helps. :)

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3 years ago

The reaction H2(g)+F2(g)?2HF(g) is spontaneous at all temperatures. A classmate calculates the entropy change for this reaction

Pachacha [2.7K]

Answer:

The correct answer is there is a mistake in the calculation. The second law of thermodynamics state that in any spontaneous process there is an increase in the entropy of the universe.

Explanation:

According to the second law a reaction will occur in a system spontaneously if the total entropy of both system and surrounding increases during the reaction.That means in case of spontaneous reaction entropy change is always positive.

But according to the question the reaction H2+F2=2HF is spontaneous in all temperature.So according to the second law of thermodynamics i can say that my classmate made a mistake in calculation that"s why his result for entropy change comes negative.

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3 years ago

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3 years ago

Identify each statement as true or false. Explain in every case.a.Ionization energies are always negative quantities.b.Oxygen ha

worty [1.4K]

Answer:

(a) FALSE

(b) FALSE

(d) FALSE

Explanation:

Ionization energy refers to the energy needed for removal of a valence electron present in valence shell of a gaseous atom.

(a) The value of ionization energy of an atom is always positive. This is because energy has to be always supplied or provided to a gaseous atom for the removal of the valence electron.

Therefore, the statement (A) is false

(b) The ionization energy of an atom increases across a period i.e. from left to right. This is because the effective nuclear charge that is experienced by the valence electron increases from left to right in the periodic table, as the atomic number increases.

So, more energy is required to remove the valence electron of fluorine as compared to oxygen.

Therefore, the ionization energy of fluorine is greater than oxygen.

Therefore, the statement (B) is false

(c) First ionization energy is energy needed for removal of first electron present in valence shell of a neutral atom. Whereas, second ionization energy is the energy needed for removal of second electron present in valence shell of a monovalent cation

The second ionization energy of an atom is always greater than the first ionization energy. This is because removing an electron from a positively charged species, requires more energy.

Therefore, the statement (C) is true

(d) The third ionization energy refers to the energy needed to remove the third electron from a divalent cation.

Therefore, the statement (D) is false

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3 years ago

Which do you think will cool down faster in? The teaspoon of water or the cup of water? Why?

777dan777 [17]

Answer:

I think the teaspoon will cool down faster.

Explanation:

The teaspoon of water will cool down faster because it is a smaller amount of water so the entire [drop] will absorb heat energy faster.

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3 years ago

1. An example of a polyatomic ion is:a) SO²-4b) Ca?c) O2d) NaCl​

1. An example of a polyatomic ion is:a) SO²-4b) Ca?c) O2d) NaCl