Why is nucleus configured the brain of the cell

11) A sample of rhenium of suspected extrasolar origin (translation: not from this solar

jarptica [38.1K]

Answer:

Atomic number 75 is dedicated to an element named rhenium and has been given Re as its chemical name.

Explanation:

With a really low concentration it is one of the rarest metals that is found in Earth's crust.

Like all other elements rhenium also has certain isotopes among with 185 and 187 are the most stable ones. Hence these two are the ones that are naturally available abundance is 34% and 63% respectively.

4 0

3 years ago

Calculate ΔH⁰298 (in kJ) for the process P(s) + 5/2 Cl2(g) → PCl5(g) from the following information.

Viefleur [7K]

Answer:

$\Delta H_{298}^{0}$ for the process is -375 kJ

Explanation:

Given reaction is a combination of the two given elementary steps.

Summation of change in standard enthalpy ( $\Delta H_{298}^{0}$ )of the two elementary reactions give $\Delta H_{298}^{0}$ of the reaction $P(s)+\frac{5}{2}Cl_{2}(g)\rightarrow PCl_{5}(g)$ .

$P(s)+\frac{3}{2}Cl_{2}(g)\rightarrow PCl_{3}(g)$ ...... $\Delta H_{1}=-287kJ$

$PCl_{3}(g)+Cl_{2}(g)\rightarrow PCl_{5}(g)$ ...... $\Delta H_{2}=-88kJ$

-----------------------------------------------------------------------------------------------------

$P(s)+\frac{5}{2}Cl_{2}(g)\rightarrow PCl_{5}(g)$

$\Delta H_{298}^{0}$ = $\Delta H_{1}+\Delta H_{2}=-287kJ-88kJ=-375kJ$

3 0

3 years ago

If a solution containing 23.81 g of lead(II) acetate is allowed to react completely with a solution containing 7.410 g of sodium

jeka57 [31]

Answer:

The correct answer is 15.80 grams.

Explanation:

The reaction taking place in the given question,

Pb(CH₃COO)₂ + Na₂SO₄ ⇒ PbSO₄ + 2NaCH₃COO

The number of moles can be calculated by using the formula,

n = weight / molecular mass

Based on the given question, the weight of lead (II) acetate is 23.81 grams and the weight of sodium sulfate is 7.410 grams.

The number of moles of Pb(CH₃COO)₂ is,

n = 23.81 g / 325.29 g/mol = 0.0732 moles

The number of moles of Na₂SO₄ is,

n = 7.410 g / 142.04 g/mol = 0.0521 moles

As one mole of lead (II) acetate needs one mole of sodium sulfate. Therefore, 0.0732 moles of lead (II) acetate needs 0.0732 moles of sodium sulfate.

However, as sodium sulfate is less, that is, 0.0521, therefore, Na₂SO₄ is a limiting reactant.

One mole of sodium sulfate produces one mole of PbSO₄. So, 0.0521 moles of Na₂SO₄ produces 0.0521 moles of PbSO₄.

Now the mass of PbSO₄ is,

mass = moles × molecular mass

mass = 0.0521 × 303.26 g/mol

mass = 15.80 grams.

6 0

3 years ago

Be sure to answer all parts. draw the product of the lewis acid-base reaction. label the electrophile and nucleophile. br2 + feb

jolli1 [7]

Br₂ + FeBr₃----->Br-Br-FeBr₃

In this reaction, FeBr₃, is a electron-deficient species that is it act as a lewis acid.

While Br₂, donates its electron to FeBr₃.

Br₂, act as a electrophile while FeBr₃ is a lewis acid.

Futher if Br₂, undergoes a reaction an aromatic ring , then that ring will attack Br₂, and it acts as a electrophile.

4 0

3 years ago

Read 2 more answers

Select all of the chirality centers in the structure. a selected atom will turn green.

scZoUnD [109]

Answer:

The answer is C is attached to four unique gatherings A, B C and D, Thus it frame two optical isomers as the perfect representations of one another.

Explanation:

A critical class of isomers in which mixes have the equivalent sub-atomic recipe and structure, yet the distinction emerges from the introduction of the gatherings in the 3D space. Optical isomers are called as enantiomers. Enantiomers are optical isomers whose identical representations are non-superimpose. They turn the plane enraptured light inverse way. Optical action is characterized as the capacity of a choral atom to pivot the plane energized light. The enantiomers that pivots the plane energized light a clockwise way is called extraordinary, while the one that turns the plane spellbound light an anticlockwise way is called rotatory. Basics , Centrality is the major behind the optical movement of a natural atom. Choral focus: A'C' particle in a particle turns into a choral focus when all the four valences of that molecule are fulfilled by synthetically unique gatherings.

4 0

3 years ago