Answer:
A scientist measures the standard enthalpy change for the following reaction to be -139.5 kj :
h2(g) + c2h4(g)c2h6(g)
based on this value and the standard enthalpies of formation for the other substances, the standard enthalpy of formation of c2h4(g) is _____ kj/mol
Explanation:
Hydrogen ΔHof (kJ/mol) ΔGof (kJ/mol) So (J/mol K)
H2 (g)
0
0
130.7
Carbon ΔHof (kJ/mol) ΔGof (kJ/mol) So (J/mol K)
C2H6 (g)
-84.7
-32.8
229.6
Answer:
83.6 g
Explanation:
The limiting reactant is carbon and oxygen is in excess.
C + O₂ ⟶ CO₂
Data:
Mass of C = 22.8 g
Mass of O₂ = 78.0 g
Mass of unreacted O₂ = 17.2 g
Calculations:
Mass of O₂ reacted = 78.0 g - 17.2 g = 60.8 g
Mass of reactants (C + O₂) = 22.8 g + 60.8 g = 83.6 g
According to the Law of Conservation of Mass, the mass of the product (CO₂) equals the sum of the masses of the reactants.
The mass of CO₂ is 83.6 g.
Answer : The net ionic equation will be,

Explanation :
In the net ionic equations, we are not include the spectator ions in the equations.
Spectator ions : The ions present on reactant and product side which do not participate in a reactions. The same ions present on both the sides.
The given balanced ionic equation will be,

The ionic equation in separated aqueous solution will be,

In this equation,
are the spectator ions.
By removing the spectator ions from the balanced ionic equation, we get the net ionic equation.
The net ionic equation will be,

Answer:
Fluorine, chlorine, bromine and iodine are grouped together because they have the same number of valence electrons.
Explanation:
Fluorine, chlorine, bromine and iodine are all found in group 7, which is the second-last column from the right. Group 7 elements are also called the "Halogens" family.
The group number also tells you the number of valence electrons that the elements have in that group. Valence electrons mean the outermost electrons (See picture).
For example, fluorine has two shells (the circles with dots on them). The outermost electrons, or valence electrons, are the dots on the biggest circle. There are 7 dots, so there are 7 valence electrons, which corresponds with Group "7".
A full shell (except the for first shell) is when there are 8 dots. Since 7 is so close to 8, Halogens are very reactive.
Fluorine, chlorine, bromine and iodine all have 7 valence electrons and are in the Halogens family, which are very reactive.
Here N H 4 O H { NH }_{ 4 }OH NH4OH is not a strong electrolyte because it doesn't dissociates completely.