Answer:
ΔH rxn = -1010 kJ/molC₂H₂
Explanation:
To obtain the enthalpy change for a reaction from bond energies what we do is to make an inventory of the bonds broken and formed for the balanced chemical reaction:
C₂H₂ + 5/2O₂ ⇒ 2CO₂ + H₂O
Bond Broken Bonds Formed
2 C-H + 1 C≡C + 5/2 O=O 4C=O + 2 H-O
Enthalpy bonds broken:
2 mol (456 kJ/mol)+ 1 mol (962 kJ/mol) + 5/2 mol (499 kJ/mol) = 3121.5 kJ
Enthalpy bond formed:
4 mol (802 kJ/mol) + 2 mol (462 kJ/mol) = 4132.0 kJ
ΔH rxn = H broken - H formed = 3121.5 kJ - 4132.0 kJ = - 1010 kJ (per mol C₂H₂ )
Answer:
1.78 × 10²⁶ Atoms
Explanation:
Relation between number of molecules and moles is,
No. of Molecules = Moles × 6.022 × 10²³ Molecules/mol
No. of Molecules = 99 mol × 6.022 × 10²³ Molecules/mol
No. of Molecules = 5.96 × 10²⁵ Molecules
Also, In CO₂ Molecule there are 3 atoms.
So,
No. of atoms = 5.96 × 10²⁵ Molecules × 3
No. of atoms = 1.78 × 10²⁶ Atoms
Answer:
The final state of the substance is a gas.
The sample is initially a liquid. One or more phase changes will occur.
Explanation:
Let's consider the phase diagram for Argon (not to scale).
<em>A sample of argon is initially at a pressure of 49.6 atm and a temperature of 101.4 K. The pressure on the sample is reduced to 0.680 atm at a constant temperature of 101.4 K. Which of the following are true? Choose all that apply </em>
<em>The final state of the substance is a gas.</em> TRUE. At 0.680 atm and 101.4 K, the substance is a gas.
<em>The gas initially present will solidify.</em> FALSE. Initially, Ar is present as a liquid.
<em>The final state of the substance is a solid.</em> FALSE.
<em>The sample is initially a liquid. One or more phase changes will occur.</em> TRUE. The sample is initially liquid and only one phase change will occur.
The balanced equation that shows the reaction between oxalic acid and permanganate ion in an acidic medium is: 2MnO4- + 5H2C2O4 + 6H+ -> 2Mn(2+) + 10CO2 + 8H2O. Thus, 1 mole of oxalic acid reacts with 0.4 mole of permanganate ion. This was obtained using stoichiometry:
1 mol H2C2O4 x (2 mol MnO4-/ 5 mol H2C2O4) = 0.4 mol MnO4-
In this redox reaction, the permanganate is reduced to manganese(II) ion.
Neutralization reactions are the reactions type which form salts.
Explanation:
Salts are formed by ionic bonds when the oxidation states of anions and cations are equal and have opposite signs. So one should be highly electronegative in nature and another should be highly electropositive in nature. So the electropositive element will be ready to give electrons and the electronegative element will be ready to accept all the electrons given by the electropositive element. As a whole the compound will be neutrally charged by adding of equal number of positively charged and negatively charged ions.
The reduction or addition of electrons will be occurring in cations and the oxidation or removal of electrons will be occurring in anions.
So the salt formation is based on neutralization reactions.
