Given these reactions, X ( s ) + 1 2 O 2 ( g ) ⟶ XO ( s ) Δ H = − 668.5 k J / m o l XCO 3 ( s ) ⟶ XO ( s ) + CO 2 ( g ) Δ H = + 384.3 k J / m o l what is Δ H for this reaction? X ( s ) + 1 2 O 2 ( g ) + CO 2 ( g ) ⟶ XCO 3 ( s )


Answer 1

Answer: The \Delta H^o_(rxn) for the reaction is -1052.8 kJ.


Hess’s law of constant heat summation states that the amount of heat absorbed or evolved in a given chemical equation remains the same whether the process occurs in one step or several steps.

According to this law, the chemical equation is treated as ordinary algebraic expressions and can be added or subtracted to yield the required equation. This means that the enthalpy change of the overall reaction is equal to the sum of the enthalpy changes of the intermediate reactions.

The given chemical reaction follows:

X(s)+(1)/(2)O_2(g)+CO_2(g)\rightarrow XCO_3(s)      \Delta H^o_(rxn)=?

The intermediate balanced chemical reaction are:

(1) X(s)+(1)/(2)O_2(g)\rightarrow XO(s)    \Delta H_1=-668.5kJ

(2) XCO_3(s)\rightarrow XO(s)+CO_2     \Delta H_2=+384.3kJ

The expression for enthalpy of the reaction follows:

\Delta H^o_(rxn)=[1* \Delta H_1]+[1* (-\Delta H_2)]

Putting values in above equation, we get:

\Delta H^o_(rxn)=[(1* (-668.5))+(1* (-384.3))=-1052.8kJ

Hence, the \Delta H^o_(rxn) for the reaction is -1052.8 kJ.

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B. has little solvent
C. it has a lot of solvent
D. has maximum solute


The answer to your equation is C. Hope this Helps!
C. It has more solvent
To dilute a solution means to add more solvent without the addition of more solute

Please Please! help help! so stress



Sodium phosphate and calcium chloride react to form sodium chloride and calcium phosphate. If you have 379.4 grams of calcium chloride and an excess of sodium phosphate, how much calcium phosphate can you make?


Answer:- 353.3 g

Solution:- The balanced equation is:

2Na_3PO_4+3CaCl_2\rightarrow 6NaCl+Ca_3(PO_4)_2

We start with given grams of calcium chloride and convert them to moles. Then using mol ratio, the moles of calcium phosphate are calculated and converted to grams as.

Molar mass of calcium chloride is 110.98 gram per mol and molar mass of calcium phosphate is 310 gram per mol.

The set is made using dimensional analysis as:


= 353.3gCa_3(PO_4)_2

So, 353.3 grams of calcium phosphate can be formed.




How to prepare ethanoic acid from ethane


anonymous 5 years ago
First you chlorinate it in presence of light.
C2H6 + Cl2 ---hv -> C2H5Cl + HCl
Then you add aqeuos KOH to get C2H5OH
C2H5Cl+KOH-> C2H5OH+ KCl.
Then you add KMnO4 to get the rquired compound.
C2H5OH ----KMnO4 ---> CH3COOH.
C2h6 + O2 ----> CH3CooH

At standard temperature and pressure (0 ∘C and 1.00 atm ), 1.00 mol of an ideal gas occupies a volume of 22.4 L. What volume would the same amount of gas occupy at the same pressure and 55 ∘C ?


Taking into account the Charles's law, the same amount of gas at the same pressure and 55 ∘C would occupy a volume of 26.91 L.

Charles's Law consists of the relationship that exists between the volume and the temperature of a certain quantity of ideal gas, which is maintained at a constant pressure.

This law states that the volume is directly proportional to the temperature of the gas: if the temperature increases, the volume of the gas increases, while if the temperature of the gas decreases, the volume decreases.

Mathematically, Charles's law is a law that says that when the amount of gas and pressure are kept constant, the quotient that exists between the volume and the temperature will always have the same value:


Studying an initial state 1 and a final state 2, it is satisfied:


In this case, you know:

  • V1= 22.4 L
  • T1= 0 C= 273 K
  • V2= ?
  • T2= 55 C= 328 K


(22.4 L)/(273 K)=(V2)/(328 K)


V2=328 Kx(22.4 L)/(273 K)

V2= 26.91 L

Finally, the same amount of gas at the same pressure and 55 ∘C would occupy a volume of 26.91 L.

Learn more:


Explanation: this is Charles' law which states that the volume of a gas is directly proportional to the absolute temperature at contant pressure. The expression is V1/T1 = V2/T2

Making V2 the subject of the formula we have

V2 = V1 xT2/T1

= 22.4 x 328/273

= 26.9L

Convert 50g of calcium carbonate, CaCO3, into moles


            Moles  =  0.5 mol


Moles is related to mass as follow,

                                       Moles  =  Mass / M.mass   ----- (1)

           Mass  =  50 g

           M.mass  =  Ca (40) + C (12) + O₃ (16)₃  =  100 g/mol

Putting values in equation 1,

                                        Moles  =  50 g ÷ 100 g.mol⁻¹

                                        Moles  =  0.5 mol