Answer:
V = 94.24 cm3
Explanation:
Uranium metal has a very high density of 19.1 g/cm3.
d = 19.1 g/cm3
m = 1800 g
m = V × d
=> V = m/d = 1800/19.1 = 94.24 cm3
<h3>Answer:</h3>
<u>Breaking</u> chemical bonds requires energy and <u>forming</u> chemical bonds releases energy.
<h3>Explanation:</h3>
Bond Breaking is an endothermic reaction and requires energy. This energy provided to break the bond is called as bond energy. Hence, this is a non spontaneous reaction as it doesn't takes place on its own but requires energy to break them into smaller fragments.
While, Bond Forming is an exothermic reaction. When two substances come close together the formation of bond results in the release of energy. As the resulting product is stable hence, it will be lower in energy as compared to the sum of energies of the reactants. Therefore, the surplus energy is released in the form of heat.
Mass number= atomic number + number of neutrons.
A=Z+N
Z=number of protons=12
N=12
A=12+12=24
If, we have 12 protons and 10 electrons, the charge of this ion is +2
Therefore: mass number:24; charge: +2
Answer: a. mass number: 24; charge: +2
The heat of reaction : 50.6 kJ
<h3>Further explanation</h3>
Based on the principle of Hess's Law, the change in enthalpy of a reaction will be the same even though it is through several stages or ways
Reaction
N₂(g) + 2H₂(g) ⇒N₂H₄(l)
thermochemical data:
1. N₂H₄(l)+O₂(g)⇒N₂(g)+2H₂O(l) ΔH=-622.2 kJ
2. H₂(g)+1/2O₂(g)⇒H₂O(l) ΔH=-285.8 kJ
We arrange the position of the elements / compounds so that they correspond to the main reaction, and the enthalpy sign will also change
1. N₂(g)+H₂O(l) ⇒ N₂H₄(l)+O₂(g) ΔH=+622.2 kJ
2. H₂(g)+1/2O₂(g)⇒H₂O(l) ΔH=-285.8 kJ x 2 ⇒
2H₂(g)+O₂(g)⇒2H₂O(l) ΔH=-571.6 kJ
Add reaction 1 and reaction 2, and remove the same compound from different sides
1. N₂(g)+2H₂O(l) ⇒ N₂H₄(l)+O₂(g) ΔH=+622.2 kJ
2.2H₂(g)+O₂(g)⇒2H₂O(l) ΔH=-571.6 kJ
-------------------------------------------------------------------- +
N₂(g) + 2H₂(g) ⇒N₂H₄(l) ΔH=50.6 kJ
