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GREYUIT [131]
3 years ago
13

Why are the elements 57 through 71 and 89 through 102, found separately at the bottom of the table?

Chemistry
1 answer:
Dovator [93]3 years ago
8 0
Elements from 57 to 71 are Lanthanoids and from 89 to 103 are Actinoids. Simply I would say Actinoids have less similarity in chemical properties than Lanthanoids. On the other hands, Actinoids have randomized chemical strutural bonds.
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Compounds X and Y both have the formula C7H14. Both X and Y react with one molar equivalent of hydrogen in the presence of a pal
ArbitrLikvidat [17]

Answer:

See explanation and image attached

Explanation:

Alkenes undergo hydrogenation to give the corresponding alkanes. Where the structure of the original alkene is unknown, we can deduce the structure of the alkene from the structure of the products obtained when it undergoes various chemical reactions.

Now, the fact that we obtained 2-methylhexane upon hydrogenation and the two compounds had different heats of hydrogenation means that the two compounds were geometric isomers. The original compounds must have been cis-2-methyl-3-hexene and trans-2-methyl-3-hexene.

When reacted with HCl, the same compound C7H15Cl is formed because the stereo chemistry is removed.

However, we know that the trans isomer is more stable than the cis isomer hence the cis isomer always has a higher heat of hydrogenation than the trans isomer. Thus X is cis-2-methyl-3-hexene.

4 0
3 years ago
Each chemical element has an atomic number and a mass number. the atomic number refers to the number of ___________________the e
creativ13 [48]
The atomic number tells us the number of protons and electrons.
The atomic mass tells us the weight of the nucleus, which is the amount of protons and neutrons
5 0
3 years ago
Can a combination reaction be a redox reaction ?
saul85 [17]

Answer:

Yes A redox reaction can be a combination reaction.

Two elements are mixed in a combination reaction to produce a single product.

Explanation:

Example: water formula

2H2 + O2 → 2H2O

Oxygen is reduced in this reaction when electrons are transferred from hydrogen to oxygen and hydrogen is also oxidized since oxygen from hydrogen accepts electrons. Oxygen is the oxidizing agent and hydrogen is the reducing agent.

2H2 + O2 → 2H2O

4 0
3 years ago
Calculate the ph of a 0.021 m nacn solution. [ka(hcn) = 4.9  10–10]
ohaa [14]

<span>Answer is: pH of solution of sodium cyanide is 11.3.
Chemical reaction 1: NaCN(aq) → CN</span>⁻(aq) + Na⁺<span>(aq).
Chemical reaction 2: CN</span>⁻ + H₂O(l) ⇄ HCN(aq) + OH⁻<span>(aq).
c(NaCN) = c(CN</span>⁻<span>) = 0.021 M.
Ka(HCN) =  4.9·10</span>⁻¹⁰<span>.
Kb(CN</span>⁻) = 10⁻¹⁴ ÷ 4.9·10⁻¹⁰ = 2.04·10⁻⁵<span>.
Kb = [HCN] · [OH</span>⁻] / [CN⁻<span>].
[HCN] · [OH</span>⁻<span>] = x.
[CN</span>⁻<span>] = 0.021 M - x..
2.04·10</span>⁻⁵<span> = x² / (0.021 M - x).
Solve quadratic equation: x = [OH</span>⁻<span>] = 0.00198 M.
pOH = -log(0.00198 M) = 2.70.
pH = 14 - 2.70 = 11.3.</span>

4 0
2 years ago
An atom of boron has an atomic number of 5 and an atomic mass of 11. the atom contains
kirill [66]
The atom contain 6 neutrons, if that's the question
8 0
3 years ago
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