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2 years ago

Advantage of modern perodic law

Chemistry

1 answer:

mario62 [17]2 years ago

6 0

Answer:

it has made the study of chemistry systematic and easy. it acts as an aid to memory

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Give 3 importance of learning about fault

Drupady [299]

Answer:

These breaks, across which slip has occurred, are called faults. ... So understanding the types and patterns of ancient fault can help geologists to ... The faulting patterns can have enormous economic importance

3 0

3 years ago

The work function of an element is the energy required to remove an electron from the surface of the solid element. The work fun

ANEK [815]

Answer:

$\lambda=428.04\ nm$

Explanation:

The work function of the lithium = 279.7 KJ/mol (Source)

It means that

1 mole of electrons can be removed by applying of 279.7 kJ of energy.

Also,

1 mole = $6.023\times 10^{23}\ electrons$

So,

$6.023\times 10^{23}$ electrons can be removed by applying of 279.7 kJ of energy.

1 electron can be removed by applying of $\frac {279.7}{6.023\times 10^{23}}\ kJ$ of energy.

Energy required = $46.44\times 10^{-23}\ kJ$

Also,

1 kJ = 1000 J

So,

Energy required = $46.44\times 10^{-20}\ J$

Also, $E=\frac {h\times c}{\lambda}$

Where,

h is Plank's constant having value $6.626\times 10^{-34}\ Js$

c is the speed of light having value $3\times 10^8\ m/s$

So,

$46.44\times 10^{-20}=\frac {6.626\times 10^{-34}\times 3\times 10^8}{\lambda}$

$\lambda=\frac{6.626\times 10^{-34}\times 3\times 10^8}{46.44\times 10^{-20}}$

$\lambda=\frac{10^{-26}\times \:19.878}{10^{-20}\times \:46.44}$

$\lambda=\frac{19.878}{10^6\times \:46.44}$

$\lambda=4.2804\times 10^{-7}\ m$

Also,

1 m = 10⁻⁹ nm

So,

$\lambda=428.04\ nm$

4 0

3 years ago

Mg(OH)2 is a slightly soluble salt what is the Ksp expressi a. [Mg2+][20H J? b. (Mg2+][OH-]2 c. [Mg2][OH-] d. [Mg2][OH-]?

lesantik [10]

Answer:

B) $k_{sp} =[Mg_{aq} ]*[OH_{aq}]^{2}$

Explanation:

Ksp is the solubility product constant.

For a generic chemical equation

$AB_{2} = A_{aq}+2B_{aq}$

The Ksp for this generic chemical equation is

$k_{sp} =[A_{aq} ]*[B_{aq}]^{2}$

So the Ksp fot the Mg(OH)2 is

$k_{sp} =[Mg_{aq} ]*[OH_{aq}]^{2}$

5 0

3 years ago

A student uses 3.00g of a fertilizer with an npk ratio of 15-15-10, how much mgnh4po4*6h2o (mm =245.1 g/mol) should the student

postnew [5]

The correct answer is 8.89 g.

The production of MgNH₄PO₄.6H₂O is given by the equation:

NH₃ + H₃PO₄ ⇒ (NH₄)H₂PO₄

(NH₄)H₂PO₄ + MgSO₄ + 6H₂O ⇒ MgNH₄PO₄.6H₂O + H₂SO₄

This is the real fertilizer of NPK of weight 3 g.

It is given that the NPK is present in the ratio of 15-15-10.

Therefore, the moles of phosphorus found in the actual fertilizer is as follows:

% of P present as P₂O₅ in the fertilizer is (15/40) × 100 = 37.5 %

% of P = mass of P / actual mass of fertilizer

0.375 × 3 = mass of P

Mass of P = 1.125 g / 31

Moles of P = 0.03629 mol

On the basis of reaction stoichiometry,

1 mol of P in the actual fertilizer = 1 mol of P in the product

0.03629 of P

Moles of MgNH₄PO₄.6H₂O = 0.03629 mol

Mass of MgNH₄PO₄.6H₂O formed = 0.03629 mol × 245.1 g/mol

= 8.89 g

Thus, the mass of the product MgNH₄PO₄.6H₂O formed is 8.89 g.

8 0

3 years ago

Read 2 more answers

How many protons do the following have?<br> Calcium<br> Gold<br> Copper<br> Iron

Otrada [13]

Answer:

Calcium = 20 protons

Gold = 79 protons

Copper = 29 protons

Iron = 26 protons

Explanation:

Atomic Number = #protons and neutrons

Calcium (Ca)

Atomic Number: 20

Protons: 20

Gold (Au)

Atomic Number: 79

Protons: 79

Copper (Cu)

Atomic Number: 29

Protons: 29

Iron (Fe)

Atomic Number: 26

Protons: 26

4 0

3 years ago

Advantage of modern perodic law ​

Advantage of modern perodic law