Answer:
The correct answer is A Energy leaves the iron bar and enters the wood until the temperature are equal.
Explanation:
According to the law of conservation of energy or the first law thermodynamics energy neither be created nor destroyed, energy is transferred from one form to another form.
Here iron bar is placed in wood block energy is transferred from iron bar to wood until the temperatures are equal.
Explanation:
As the given chemical reaction equation is as follows.
Also, it is given that for 2 moles the energy required is 130 kcal. This means that energy required for 1 mole is calculated as follows.
1 mole = 
= 65 kcal
Hence, energy required for 7 moles will be calculated as follows.
Energy required = 
= 455 kcal
Thus, we can conclude that energy required to produce 7.00 mol 
on the basis of given reaction is 455 kcal.
Answer:
Molecules
Explanation:
If you had more than one atom chemically bonded together, then regardless of the types of atoms that are bonded, you're going to have a molecule regardless.
Answer:
D. The electron moved up to an energy level and has an energy of 21.72 x 10−19 J.
Answer:
3.657 kg
Explanation:
Given:
Enthalpy of combustion of hard coal = -35 kJ/g
Enthalpy of combustion of gasoline = 1.28 × 10⁵ kJ/gal
Density of gasoline = 0.692 g/mL
now,
The heat provide 1 gallon of gasoline provide = 1.28 × 10⁵ kJ
and,
heat provided by the 1 gram of coal = 35 kJ
or
1 kJ of heat is provided by (1/35) gram of hard coal
therefore,
For 1.28 × 10⁵ kJ of heat, mass of hard coal = 1.28 × 10⁵ kJ × (1 / 35)
or
For 1.28 × 10⁵ kJ of heat, mass of hard coal = 3657.14 grams = 3.657 kg
