Which one of the following equations is not balanced?

2 answers:

8 0

The key in the balancing of chemical reaction is to make sure that you got the exact chemical formula of the substance that is reacting and the yielded product. After getting the formula, identify first the hardest element/atom to be balanced such as Na, Zn, Cl, C, O, etc. Then proceed to the easier ones such as O, H. Make sure to note the atoms present in the molecule of the substance. Among the three equations, PCl2 + 4H2O --->H3PO4 + 5HCL is not balanced. The hardest element here is the Cl. Observe that there are 5Cls in the product side so you must add 5 to the PCl2. However, there are only 2Cl atoms and it needs 3 to balance the equation. Also, there is no P in the product side. This equation is invalid.

rewona [7]3 years ago

7 0

The third one is incorrectly balance because the are only two chlorine on the reactant side and five on the product side. The correct balanced equation is 2PCL2 + 8H2O -> 2H3PO4 + 5H2 + 4Cl. The reason HCl is broken into two parts is because it is a strong acid and would immediately dissolve if put together.

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Consider the reaction: 2 H2O (g)-->2 H2 (g) + O2 (g). ΔH=483.6 Kj/mol. If 2 moles of H2O (g) are converted H2(g) and O2(g) ag

denis-greek [22]

DE = dH - PdV

2 H2O(g) → 2 H2(g) + O2(g) 

You can see that there are 2 moles of gas in the reactants and 3 moles of gas in the products. 

1 moles of ideal gas occupies the same volume as 1 mole of any other ideal gas under the same conditions of temp and pressure. 

Since it is done under constant temp and pressure that means the volume change will be equal to the volume of 1 mole of gas 

2 moles reacts to form 3 moles 

The gas equation is 

PV = nRT 
P = pressure 
V = volume (unknown) 
n = moles (1) 
R = gas constant = 8.314 J K^-1 mol^-1 
- the gas constant is different for different units of temp and pressure (see wikki link) in this case temp and pressure are constant, and we want to put the result in an equation that has Joules in it, so we select 8.314 JK^-1mol^-1) 
T = temp in Kelvin (kelvin = deg C + 273.15 
So T = 403.15 K 

Now, you can see that PV is on one side of the equation, and we are looking to put PdV in our dE equation. So we can say 

dE = dH -dnRT (because PV = nRT) 

Also, since the gas constant is in the unit of Joules, we need to convert dH to Joules 

dH = 483.6 kJ/mol = 483600 Joules/mol 

dE = 483600 J/mol - (1.0 mol x 8.314 J mol^-1K-1 x 403.15 K) 
dE = 483600 J/mol - 3351.77 J 
dE = 480248.23 J/mol 
dE = 480.2 kJ/mol

5 0

3 years ago

Read 2 more answers

URGENT !! A substance has 55.80% carbon, 7.04% Hydrogen, and 37.16% Oxygen. What is it's empirical and molecular formula if it h

Ede4ka [16]

<h3>Answer;</h3>

Empirical formula = C₂H₃O

Molecular formula = C₁₄H₂₁O₇

<h3>Explanation;</h3>

Empirical formula

Moles of;

Carbon = 55.8 /12 = 4.65 moles

Hydrogen = 7.04/ 1 = 7.04 moles

Oxygen = 37.16/ 16 = 2.3225 moles

We then get the mole ratio;

4.65/2.3225 = 2.0

7.04/2.3225 = 3.0

2.3225/2.3225 = 1.0

Therefore;

The empirical formula = C₂H₃O

Molecular formula;

(C2H3O)n = 301.35 g

(12 ×2 + 3× 1 + 16×1)n = 301.35

43n = 301.35

n = 7

Therefore;

Molecular formula = (C2H3O)7

 = C₁₄H₂₁O₇

6 0

4 years ago

Describe what is happening in this chemical equation: Al2(SiO3)3 + NaOH → Na(SiO3)3 + Al2OH Please Help ASAP

WITCHER [35]

Answer:

Double replacement reaction

Explanation:

This is what is known as a double replacement reaction. The two parts of each molecule separate and recombine to form two new compounds. For instance, $Al_2(SiO_3)_3$ separates into $Al_2$ and $(SiO_3)_3$ , while $NaOH$ separates into $Na$ and $OH$ , and then they recombine with the other compound.