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3 years ago

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rank the group 1a elements tested in order of increasing energy emission when electrons returns to the ground state. explain thi

s pattern in terms of changes in energy levels.

1 answer:

labwork [276]3 years ago

3 0

<em>Answer:</em>

The increasing order of energy emission is as follow

Li < Na < K < Rb < Cs

<em>Explanation:</em>

The Characteristic colors of alkali metals are

Li-crimson<em> red</em>
Na- golden<em> yellow</em>
K- pale <em>violet</em>
Rb and Cs- <em>violet</em>

These flame color show that when we moved from down the group, the wavelength decreases (frequency increases).
As the color of Li is red that shows ,it has less emission energy as compare to Rb and Cs that have color violet (more emission energy).

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Answer:

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Picture of gas laws question below:

Vera_Pavlovna [14]

Volume of the tank is 5.5 litres.

Explanation:

mass of the CO2 is given 8.6 grams

Pressure of the gas is 89 Kilopascal which is 0.8762 atm

Temperature of the gas is 29 degrees ( 0 degrees +273.5= K) so (29+273)

R = gas constant 0.0821 liter atmosphere per kelvin)

FROM THE IDEAL GAS LAW

PV=nRT ( P Pressure, V Volume, n is number of moles of gas, R gas constant, Temperature in Kelvin)

no of moles = mass/atomic mass

= 8.6/44

= 0.195 moles

now putting the values in equation

V=nRT/P

= 0.195*0.0821*302/ 0.8762

= 5.5 litres.

As the carbon dioxide gas occupies the volume os the tank hence volume of tank is 5.5 litres.

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3 years ago

4.41 g of propane gas (C3H8) is injected into a bomb calorimeter and ignited with excess oxygen, according to the reaction below

gayaneshka [121]

Answer : The heat of the reaction is -221.6 kJ

Explanation :

Heat released by the reaction = Heat absorbed by the calorimeter

$q_{rxn}=-q_{cal}$

$q_{cal}=c_{cal}\times \Delta T$

where,

$q_{rxn}$ = heat released by the reaction = ?

$q_{cal}$ = heat absorbed by the calorimeter

$c_{cal}$ = specific heat of calorimeter = $97.1kJ/^oC=97100J/^oC$

$\Delta T$ = change in temperature = $(T_{final}-T_{initial})=(27.282-25.000)=2.282^oC$

Now put all the given values in the above formula, we get:

$q_{cal}=(97100J/^oC)\times (2.282^oC)$

$q_{cal}=221582.2J=221.6kJ$

As, $q_{rxn}=-q_{cal}$

So, $q_{rxn}=-221.6kJ$

Thus, the heat of the reaction is -221.6 kJ

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3 years ago

What is 190 K in degrees Celsius? Show your work for full credit.

saveliy_v [14]

Answer:

-83.15

Explanation:

190K − 273.15 = -83.15°C

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3 years ago

Reactions are classified as either exothermic or endothermic. . ____________ reactions feel hot (e.g., a burning campfire), wher

creativ13 [48]

Answer:

Exothermic reactions feel hot

Endothermic reactions feel cool

Explanation:

In an exothermic reaction, heat is given out by the system. The energy of the reactants is greater than that of the products hence the excess energy is given off as heat. The reaction vessel feels hot.

In an endothermic reaction, the energy of products is greater than that of the reactants hence energy is taken into the system and the reaction vessel feels cool.

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3 years ago