Given :
A compound has a molar mass of 129 g/mol .
Empirical formula of compound is C₂H₅N .
To Find :
The molecular formula of the compound.
Solution :
Empirical mass of compound :

Now, n-factor is :

Multiplying each atom in the formula by 3 , we get :
Molecular Formula, C₆H₁₅N₃
Answer:
a) 
b) 
d) 
d) 
Explanation:
From the question we are told that:
Moles of N2 
Atmospheric pressure 
Temperature 

Initial heat 
a)
Generally the equation for change in temperature is mathematically given by

Where




b)
Generally the equation for ideal gas is mathematically given by

For v double


Therefore



Total Work-done 



c)
Generally the equation for amount of heat added is mathematically given by



d)
Generally the equation for change in internal energy of the gas is mathematically given by



Answer:
3.64g
Explanation:
Given parameters:
Mass of NH₃ = 18.1g
Mass of Cu₂O = 90.4g
Unknown:
Limiting reactant = ?
Mass of N₂ formed = ?
Solution:
The reaction equation is given as:
Cu₂O + 2NH₃ → 6Cu + N₂ + 3H₂O
The limiting reactant is the one in short supply in the reaction. Let us find the number of moles of the given species;
Number of moles =
Molar mass of Cu₂O = 2(63.6) + 16 = 143.2g/mol
Molar mass of NH₃ = 14 + 3(1) = 17g/mol
Number of moles of Cu₂O =
= 0.13moles
Number of moles of NH₃ =
= 5.32moles
From this reaction;
1 mole of Cu₂O combines with 2 mole of NH₃
So 0.13moles of Cu₂O will combine with 0.13 x 2 mole of NH₃
= 0.26moles of NH₃
Therefore, Cu₂O is the limiting reactant. Ammonia is in excess;
Mass of N₂;
Mass = number of moles x molar mass
1 mole of Cu₂O will produce 1 mole of N₂
0.13 mole of Cu₂O will produce 0.13 mole of N₂
Mass = 0.13 x (2 x 14) = 3.64g
Answer:
The change in internal energy of the heater is 0 kJ
Explanation:
∆U = Q - W
Q is quantity of heat transferred = 1 kJ
W is work done on the heater = 1 kJ
Change in internal energy (∆U) = 1 - 1 = 0 kJ