Answer:
91.7 kJ
Explanation:
Step 1: Given data
- Mass of ammonia (m): 66.7 g
- Molar heat of vaporization of ammonia (ΔH°vap): 23.4 kJ/mol
Step 2: Calculate the moles (n) corresponding to 66.7 g of ammonia
The molar mass of ammonia is 17.03 g/mol.
66.7 g × 1 mol/17.03 g = 3.92 mol
Step 3: Calculate the heat (Q) required to boil 3.92 moles of ammonia
We will use the following expression.
Q = ΔH°vap × n
Q = 23.4 kJ/mol × 3.92 mol = 91.7 kJ
It is an example of physical change. The molecules are not changing, so it is not chemical, and a physical property is something that a physical thing has.
Answer:
8.58 g/cm3
Explanation:
density = mass / volume
be attention that the question gives u the length of
one side of the cube so u should calculate the volume
of the cube using your information of math .
1st we calculate the volume of the cube :
V of cube = a 3= axaxa
= 0.250 x0.250 x0.250
= 0.0156 cm3
2nd step
density = mass/volume
= 0.134/ 0.0156 = 8.58 g/cm3
