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2 years ago

Can someone help me plz

Chemistry

1 answer:

Sidana [21]2 years ago

4 0

That answer is what characteristic you have.

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JOE BIDEN GOT ELECTED

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Organisms that breakdown waste and dead organisms and return the raw materials to the environment is called

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2 years ago

When 15.3 g of sodium nitrate, NaNO3,was dissolved in water in a calorimeter, the temperature fell from 25.00oC to 21.56oC. If t

satela [25.4K]

Answer:

20.468 kilo Joules is the enthalpy change when one mole of sodium nitrate dissolves.

Explanation:

Heat lost by solution ad calorimeter = Q

Heat capacity of solution ad calorimeter = C = 1071 J/°C

Change in temperature = ΔT = 21.56°C - 25.00°C = -3.44°C

$Q=C\times Delta T$

$Q=1071 J/^oC\times (-3.44^oC)=-3,684.24 J$

Heat gained by sodium nitrate = -Q = -(-3,684.24 J)=3,684.24 J

Moles of sodium nitrate = $\frac{15.3 g}{85 g/mol}=0.18 mol$

When 0.18 mole of sodium nitrate was dissolved in water 3,684.24 joulesof heat was absorbed by it.

Then heat absorbed by 1 mole of sodium nitrate :

$\frac{3,684.24 J}{0.18}=20,468 J=20.468 kJ$

1 J = 0.001 kJ

20.468 kilo Joules is the enthalpy change when one mole of sodium nitrate dissolves.

8 0

3 years ago

Arrange the elements in decreasing order of first ionization energy.

just olya [345]

Answer:

The decreasing order of first ionization energy: Se > Ge > In > Cs

The decreasing order of first ionization energy: x > y > z

Explanation:

Ionization energy refers to the energy needed to completely pull out an electron from the valence shell of a neutral gaseous atom.

First ionization energy is the energy involved in the removal of first valence electron.

In the periodic table, down the group, as atomic radius of elements increases, the ionization energy decreases

Whereas, across a period, as atomic radius of elements decreases, the ionization energy increases.

PART (A):

Position of the given elements in the periodic table:

Indium (In): Group 13, period 5

Germanium (Ge): Group 14, period 4

Selenium (Se): Group 16, period 4

Caesium (Cs): Group 1, period 6

Thus, the increasing order of atomic radius: Se < Ge < In < Cs

Therefore, the decreasing order of first ionization energy: Se > Ge > In > Cs

PART (B):

Given elements:

element x: radius = 110 pm

element y: radius = 199 pm

element z: radius = 257 pm

Thus, the increasing order of atomic radius: x < y < z

Therefore, the decreasing order of first ionization energy: x > y > z

5 0

3 years ago