Answer:
1. B, D,
2.A, F
Explanation:
1. According to the law of conservation of mass, In a course of chemical reaction, matter can neither be created nor destroyed but can be changed from one form to another. This means the amount of matter at the begining and ending of a reaction must be thesame.
2. Chemical reaction is not easily reversible. when gas is produced, provided the reaction system is an open system, the gas cannot be recovered and the reactants cannot be recovered from the products. likewise color change are attributed to chemical reaction
Answer:
2.01V ( To three significant digits)
Explanation:
First we show the standard reduction potentials of Cu2+(aq)/Cu(s) system and Al3+(aq)/Al(s) system. We can clearly see from the balanced redox reaction equation that aluminium is the anode and was the oxidized specie while copper is the cathode and was the reduced specie. This observation is necessary when substituting values of concentration into the Nernst equation.
The next thing to do is to obtain the standard cell potential as shown in the image attached and subsequently substitute values of concentration and standard cell potential into the Nernst equation as shown. This gives the cell potential under the given conditions.
Answer:
693K
Explanation:
The enthalpy change in the iron is 3690J
We now apply the formula for enthalpy change which is ΔH=mC∅ where ∅ is the temperature change, m the mass of the substance, and C the specific heat capacity for the substance.
ΔH in this case is 3690J.
Therefore 3690J=21.5g×0.449J/g.K×∅
as we are looking for ∅, we make it the subject of the formula.
∅=3690J/(21.5g×0.44J/g)
∅=390
Temperature=30°C +390
=420°+273
=693K
Answer:
Mass = 9.58 g
Explanation:
Given data:
Mass of Fe₂O₃ formed = ?
Mass of Fe = 6.7 g
Solution:
Chemical equation:
4Fe + 3O₂ → 2Fe₂O₃
Number of moles of Fe:
Number of moles = mass/molar mass
Number of moles = 6.7 g/ 55.8 g/mol
Number of moles = 0.12 mol
now we will compare the moles of Fe and Fe₂O₃.
Fe : Fe₂O₃
4 : 2
0.12 : 2/4×0.12 = 0.06 mol
Mass of Fe₂O₃:
Mass = number of moles × molar mass
Mass = 0.06 mol × 159.69 g/mol
Mass = 9.58 g
