Answer:
D. A compound can be separated into two or more elements through a chemical reaction.
Explanation:
By method of elimination, we are going t obtain the correct option.
A. A compound is made up of a single atom.
This is wrong because, a compound can contain more than one atom. An example is H2O
B. A compound is made up of many atoms that are all the same type.
This is wrong because a compound can contain atoms of different elements. An example is H2O. It contains atoms of hydrogen and oxygen.
C. A compound can be separated into two or more elements through physical processes.
This is wrong. H2O being a compound cannot be separated by ordinary physical means.
D. A compound can be separated into two or more elements through a chemical reaction.
This is the correct option.
Answer:
412.1kJ
Explanation:
For the reaction , from the question -
4Fe (s) + 3O₂ (g) → 2Fe₂O₃ (s)
Δ Hrxn = Δ H°f (products) - Δ H°f (reactants)
In case the compound is in its standard state , enthalphy of formation is zero
Hence ,
for the above reaction ,
ΔHrxn =( 2 * Δ H° (Fe₂O₃ )) - [ ( 4 *Δ H° Fe ) + (3 * Δ H° O₂ )]
The value for Δ H°(Fe₂O₃ ) = - 824.2kJ/mol
Δ H° Fe = 0
Δ H° O₂ = 0
Putting in the above equation ,
ΔH rxn = ( 2 * Δ H° (Fe₂O₃ )) - 0
ΔHrxn = 2× - 824.2 kJ / mol = - 1648.4 kJ/mol
- 1648.4 kJ/mol , this much heat is released by the buring of 4 mol of Fe.
Hence ,
for 1 mol of Fe ,
- 1648.4 kJ/mol / 4 = 412.1kJ
Answer:
When i cat climbs a tree it is using energy that was stored away. When you eat you are storing that energy in the food. when you cimb a tree you are burning calorius from that meal.