Answer:
Explanation:
Combustion reaction is given below,
C₂H₅OH(l) + 3O₂(g) ⇒ 2CO₂(g) + 3H₂O(g)
Provided that such a combustion has a normal enthalpy,
ΔH°rxn = -1270 kJ/mol
That would be 1 mol reacting to release of ethanol,
⇒ -1270 kJ of heat
Now,
0.383 Ethanol mol responds to release or unlock,
(c) Determine the final temperature of the air in the room after the combustion.
Given that :
specific heat c = 1.005 J/(g. °C)
m = 5.56 ×10⁴ g
Using the relation:
q = mcΔT
- 486.34 = 5.56 ×10⁴ × 1.005 × ΔT
ΔT= (486.34 × 1000 )/5.56×10⁴ × 1.005
ΔT= 836.88 °C
ΔT= T₂ - T₁
T₂ = ΔT + T₁
T₂ = 836.88 °C + 21.7°C
T₂ = 858.58 °C
Therefore, the final temperature of the air in the room after combustion is 858.58 °C
Answer:
A. 0.603
Explanation:
Mass fraction of an element in a substance = mass of that element / total mass of the substance.
Mass of magnesium = 24.3g/mol
Mass of oxygen = 16g/mol
Total mass of MgO = 24.3+16 = 40.3g/mol
Hence, the mass fraction of magnesium in Magnesium oxide =
24.3/40.3
= 0.6029
= 0.603
Another way is to divide the percentage by mass of magnesium by 100 i.e. 60.3% = 60.3/100
= 0.603
Answer is: C. CaCl2.
Name of this chemical compounds is calcium chloride.
Calcium chloride is a inorganic salt with ionic bonds between calcium and chlorine.
It is a colorless crystalline solid at room temperature, highly soluble in water.
Calcium form cation with positive charge 2+ and chlorine form anion with negative charge 1-.
Electron configuration of calcium atom: ₂₀Ca 1s² 2s² 2p⁶ 3s² 3p⁶ 4s².
Atomic number of calcium is 20, it means that it has 20 protons and 20 electrons, so atom of calcium is neutral.
When calcium lost two electrons, it will have 20 protons (positive charge) and 18 electrons (negative charge), which means it has two protons more and it has +2 oxidation number.
Halogens are a group of elements found in the periodic table. They are the elements found in Group VIIA. It consists only of five chemical elements which are fluorine, chlorine, bromine, iodine and astatine. They are called as such because they are the salt formers.
