1) Reaction: 3Mg + N₂ → Mg₃N₂.
m(Mg) = 0,225 g
n(Mg) = 0,225 g ÷ 24,3 g/mol = 0,009 mol.
n(Mg) : n(N₂) = 3 : 1
n₁(N₂) = 0,003 mol.
n₂(N₂) = 0,5331 ÷ 28 = 0,019 mol.
n₃(N₂) = 0,019 mol - 0,003 mol = 0,016, m(N₂) = 0,016mol·28g/mol=0,4467g.
or simpler: m(N₂) = 0,225 g + 0,5331 - 0,3114 g = 0,4467 g.
2) Answer is: 6 <span>of fluorine atoms are combined with one uranium atom.
</span>m(U) = 209 g.
m(F) = 100 g.
n(U) = m(U) ÷ M(U)
n(U) = 209 g ÷ 238 g/mol.
n(U) = 0,878 mol.
n(F) = m(F) ÷ M(F)
n(F) = 5,263 mol
n(U) : n(F) = 0,878 mol : 5,263 mol /:0,878.
n(U) : n(F) = 1 : 6.
n - amount of substance
Answer : The partial pressure of nitrogen gas is, 2.94 atm
Explanation:
According top the Henry's Law, the concentration of a gas in a liquid is directly proportional to the partial pressure of the gas.


is Henry's constant.
or,

where,
= initial concentration of gas = 
= final concentration of gas = 
= initial partial pressure of gas = 0.78 atm
= final partial pressure of gas = ?
Now put all the given values in the above formula, we get the final partial pressure of the gas.


Therefore, the partial pressure of nitrogen gas is, 2.94 atm
Answer:

Explanation:
When water changes from ice (solid) to water (liquid), it is melting or fusion. Therefore, we can use the following formula to find energy:

where <em>q</em> is the energy, <em>m </em>is the mass, and <em>Hf</em> is the heat of fusion.
1. Define Values
The mass is 150 grams. The heat of fusion for water is 334 Joules per gram.

2. Calculate Energy
Substitute the values into the formula.

Multiply. Note that the grams (g) will cancel each other out and leave Joules as our units.


3. Convert Units
We found the answer in joules, but the question asks for kilojoules, so we must convert.
There are 1000 Joules in 1 kilojoule. Therefore, we can divide the joules calculated by 1000.



<u>50.1 kilojoules </u>are needed to change 150 grams of ice to water.