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3 years ago

It is possible for a particular element to have various numbers of neutrons. True False

Chemistry

1 answer:

umka2103 [35]3 years ago

7 0

Answer:

True

Explanation:

Every element is constituted by atoms with the same atomic number, which is the number of protons in their nuclei. So, all the atoms of a same element have the same number of protons.

For instance, the element sodium has atomic number 11, and all its atoms have 11 protons.

The atomic number identifies uniquely every element.

In the atomic nuclei there are protons and neutrons. Neutrons can vary from one atom of a particular element to another atom of the same element. That is what the term isotope accounts for. Isotopes are atoms with the same atomic number and different number of neutrons.

Most elements have different isotopes. The atomic mass of fifferent isotopes of a particular element will differ among them, because the neutrons account for the mass.

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Give the formula for the alkene containing 15 carbons.

STALIN [3.7K]

C15H32

should b the answer

7 0

4 years ago

Is there a way to tell whether or not to put two double bonds or not. For example SeS2 seems to work if it has two double bonds

Nina [5.8K]

Your first step should be to analyse the compound. For example, if the compound is carbon, you know it always has a valence of four, so, if it has a formula C2H4 (ethylene) it obviously has a double bond. There are difficulties here because benzene C6H6 can be considered to have 6 1.5 C-C bonds, being aromatic.

A second step is to look at its structure. Double bonds are traditionally shorter than single bonds; triple bonds shorter still. Covalent bonds do have typical lengths, nevertheless you can still have problems.

A third step is to consider reactivity. For example, if you have a C=C double bond, you can add, say, bromine to it Thus C2H4 gives C2H4Br2, and by adding two bromine atoms you know you have one double bond. Again, benzene becomes an awkward molecule, but because of this, you know benzene does not have double bonds in the traditional sense

8 0

3 years ago

The arsenic in a 1.223 g sample of a pesticide was converted to H3AsO4 by suitable treatment. The acid was then neutralized, and

Vladimir79 [104]

Answer:

5.471% As₂O₃ in the sample.

Explanation:

...the reaction is: Ag+ + SCN- => AgSCN(s) Calculate the percent As2O3 in the sample. (F.W. As2O3 = 197.84 g/mol).

First, with the amount of KSCN we can find the moles of Ag in the filtrates. As we know the amount of Ag added we can know the precipitate of Ag and the moles of AsO₄ = 1/2 moles of As₂O₃ in the sample:

Moles KSCN = Moles Ag⁺ in the filtrate:

0.01127L * (0.100mol / L)= 0.001127moles Ag⁺

Total moles Ag⁺:

0.0400L * (0.0781mol/L) = 0.0031564 moles Ag⁺

Moles of Ag⁺ in the precipitate:

0.0031564 - 0.001127 = 0.0020294 moles Ag⁺

Moles AsO₄ = Moles As:

0.0020294 moles Ag⁺ * (1mol As / 3 moles Ag⁺) = 6.765x10⁻⁴ moles AsO₄

Moles As₂O₃:

6.765x10⁻⁴ moles AsO₄ * (1 mol As₂O₃ / 2 mol AsO₄) =

3.382x10⁻⁴ moles As₂O₃

Mass As₂O₃:

3.382x10⁻⁴ moles As₂O₃ * (197.84g/mol) = 0.0669g As₂O₃

Percent is:

0.0669g As₂O₃ / 1.223g sample * 100 =

<h3>5.471% As₂O₃ in the sample</h3>

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Answer:

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