D= M/V so, D=300/40 wich is 7.5 so D= 7.5g/m3
Answer: see figure attached and explanation below.
Explanation:
1) Chemical equation (given):
Fe + CuCl₂ → Cu + FeCl₂
2) ΔHf reactants: -256 kJ/mol (given)
3) ΔHf products: - 321 kJ/mol (given)
4) ΔH reaction = ΔHf products - ΔHf reactants = - 321 kJ/mol - (- 256 kJ/mol) = - 65 kJ/mol
5) Conclusion:
i) Since ΔHf of products is less (more negative) than ΔHf of reactants, the reaction is exhotermic: the reaction released energy, which is the reason why the products content less potential energy than the reactants.
ii) Then, the energy diagram is the typical one of an exothermic reaction: the products start a certain potential energy level, the energy incrases until reaching the activation energy (the energy barrier to form the activated complex) and then energy decreases until a level below the energy of the reactants.
iii) See the attached figure with such kind of diagram showing the products at a lower level than the reactans
Answer:
MoClBr₂
Explanation:
First we calculate the mass of bromine in the compound:
- 300.00 g - (82.46224 g + 45.741 g) = 171.79676 g
Then we<u> calculate the number of moles of each element</u>, using their <em>respective molar masses</em>:
- 82.46224 g Mo ÷ 95.95 g/mol = 0.9594 mol Mo
- 45.741 g Cl ÷ 35.45 g/mol = 1.290 mol Cl
- 171.79676 g Br ÷79.9 g/mol = 2.150 mol Br
Now we <u>divide those numbers of moles by the lowest number among them</u>:
- 0.9594 mol Mo / 0.9594 = 1
- 1.290 mol Cl / 0.9594 = 1.34 ≅ 1
- 2.150 mol Br / 0.9594 = 2.24 ≅ 2
Meaning the empirical formula is MoClBr₂.