Answer:
Coefficient
Explanation:
Chemical equation:
aA + bB → dD
This equation shows that reaction is balanced by coefficient q,b and d.
Reactant coefficients Product Coefficient
A a D d
B b
Every balanced equation follow the law of conservation of mass.
Law of conservation of mass:
According to the law of conservation mass, mass can neither be created nor destroyed in a chemical equation.
Explanation:
This law was given by french chemist Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.
For example:
In given photosynthesis reaction:
6CO₂ + 6H₂O + energy → C₆H₁₂O₆ + 6O₂
there are six carbon atoms, eighteen oxygen atoms and twelve hydrogen atoms on the both side of equation so this reaction followed the law of conservation of mass. The numbers 6 with CO₂, 6 with H₂O and 6 with O₂ are coefficient which balance the equation.
Answer: The enthalpy of formation of
is -396 kJ/mol
Explanation:
Calculating the enthalpy of formation of 
The chemical equation for the combustion of propane follows:

The equation for the enthalpy change of the above reaction is:
![\Delta H^o_{rxn}=[(2\times \Delta H^o_f_{(SO_3(g))})]-[(2\times \Delta H^o_f_{(SO_2(g))})+(1\times \Delta H^o_f_{(O_2(g))})]](https://tex.z-dn.net/?f=%5CDelta%20H%5Eo_%7Brxn%7D%3D%5B%282%5Ctimes%20%5CDelta%20H%5Eo_f_%7B%28SO_3%28g%29%29%7D%29%5D-%5B%282%5Ctimes%20%5CDelta%20H%5Eo_f_%7B%28SO_2%28g%29%29%7D%29%2B%281%5Ctimes%20%5CDelta%20H%5Eo_f_%7B%28O_2%28g%29%29%7D%29%5D)
We are given:

Putting values in above equation, we get:
![-198=[(2\times \Delta H^o_f_{(SO_3(g))})]-[(2\times \Delta -297)+(1\times (0))]\\\\\Delta H^o_f_{(SO_3(g))}=-396kJ/mol](https://tex.z-dn.net/?f=-198%3D%5B%282%5Ctimes%20%5CDelta%20H%5Eo_f_%7B%28SO_3%28g%29%29%7D%29%5D-%5B%282%5Ctimes%20%5CDelta%20-297%29%2B%281%5Ctimes%20%280%29%29%5D%5C%5C%5C%5C%5CDelta%20H%5Eo_f_%7B%28SO_3%28g%29%29%7D%3D-396kJ%2Fmol)
The enthalpy of formation of
is -396 kJ/mol
There are no numbers provided so I will try to explain the equation. If you want to find the percent error you would do theoretical (the number it’s supposed to be) minus experimental (the number you got in the experiment) over the theoretical value (same as the first one.) You must multiply this by 100 in order to show the actual percentage rather than very low decimals. You want the percent error to be as low as possible because the lower it is the less mistakes happened. Mistakes can include too much/less of solvent, solution, or the glassware wasn’t clean enough, and much much more.
I hope this helps!
Please mark the brainliest if it does! (:
Volume:
2.00 x 11.0 x 11.0 => 242 cm³
mass : 213 g
D = m / V
D = 213 / 242
D = 0.880 g/cm³
Answer B
hope this helps!