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3 years ago

What is a chemical element?

Chemistry

2 answers:

VladimirAG [237]3 years ago

8 0

A pure chemical substance made of one type of atom

Sedaia [141]3 years ago

7 0

Answer: O a pure chemical substance made of one type of atom

A chemical element is a pure chemical substance made of one type of atom. 

Explanation:

Each chemical element will be pure and they will be distinguished chemical properties and they are made up of one type of atom.

So each element in the periodic table of a chemical element which will be similar to single atom of each element. They are the smallest element as they are made of one atom only which cannot be divided further like one carbon element cannot be divided further to half or quarter of carbon element.

So the properties of each chemical element is the properties of single atom of the element.

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Use the given data at 500 K to calculate ΔG°for the reaction

Anton [14]

Answer : The value of $\Delta G^o$ for the reaction is -959.1 kJ

Explanation :

The given balanced chemical reaction is,

$2H_2S(g)+3O_2(g)\rightarrow 2H_2O(g)+2SO_2(g)$

First we have to calculate the enthalpy of reaction $(\Delta H^o)$ .

$\Delta H^o=H_f_{product}-H_f_{reactant}$

$\Delta H^o=[n_{H_2O}\times \Delta H_f^0_{(H_2O)}+n_{SO_2}\times \Delta H_f^0_{(SO_2)}]-[n_{H_2S}\times \Delta H_f^0_{(H_2S)}+n_{O_2}\times \Delta H_f^0_{(O_2)}]$

where,

$\Delta H^o$ = enthalpy of reaction = ?

n = number of moles

$\Delta H_f^0$ = standard enthalpy of formation

Now put all the given values in this expression, we get:

$\Delta H^o=[2mole\times (-242kJ/mol)+2mole\times (-296.8kJ/mol)}]-[2mole\times (-21kJ/mol)+3mole\times (0kJ/mol)]$

$\Delta H^o=-1035.6kJ=-1035600J$

conversion used : (1 kJ = 1000 J)

Now we have to calculate the entropy of reaction $(\Delta S^o)$ .

$\Delta S^o=S_f_{product}-S_f_{reactant}$

$\Delta S^o=[n_{H_2O}\times \Delta S_f^0_{(H_2O)}+n_{SO_2}\times \Delta S_f^0_{(SO_2)}]-[n_{H_2S}\times \Delta S_f^0_{(H_2S)}+n_{O_2}\times \Delta S_f^0_{(O_2)}]$

where,

$\Delta S^o$ = entropy of reaction = ?

n = number of moles

$\Delta S_f^0$ = standard entropy of formation

Now put all the given values in this expression, we get:

$\Delta S^o=[2mole\times (189J/K.mol)+2mole\times (248J/K.mol)}]-[2mole\times (206J/K.mol)+3mole\times (205J/K.mol)]$

$\Delta S^o=-153J/K$

Now we have to calculate the Gibbs free energy of reaction $(\Delta G^o)$ .

As we know that,

$\Delta G^o=\Delta H^o-T\Delta S^o$

At room temperature, the temperature is 500 K.

$\Delta G^o=(-1035600J)-(500K\times -153J/K)$

$\Delta G^o=-959100J=-959.1kJ$

Therefore, the value of $\Delta G^o$ for the reaction is -959.1 kJ

3 0

3 years ago

What effect does mass have on an objects density?

xz_007 [3.2K]

The density of an object or quantity of matter is its mass divided by its volume.

6 0

3 years ago

What is the last step in the scientific method?

nataly862011 [7]

Answer:

Explanation:

Because do all of that and then you do a conclusion

8 0

3 years ago

HELP 20 points!

monitta

Answer:

The limiting reagent is the reactant that is completely used up in a reaction, and thus determines when the reaction stops. ... The limiting reagent is the one that is totally consumed; it limits the reaction from continuing because there is none left to react with the in-excess reactant.

Explanation:

5 0

3 years ago

What point A on the phase diagram called?

Mariana [72]

Answer:

D) the critical point

Explanation:

Point A is the critical point in phase diagram. This is the highest temperature and pressure at which a pure material can exist in vapor/liquid equilibrium. Pretty cool!

6 0

3 years ago