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:
6.88 mg
Explanation:
Step 1: Calculate the mass of ³²P in 175 mg of Na₃³²PO₄
The mass ratio of Na₃³²PO₄ to ³²P is 148.91:31.97.
175 mg g Na₃³²PO₄ × 31.97 g ³²P/148.91 g Na₃³²PO₄ = 37.6 mg ³²P
Step 2: Calculate the rate constant for the decay of ³²P
The half-life (t1/2) is 14.3 days. We can calculate k using the following expression.
k = ln2/ t1/2 = ln2 / 14.3 d = 0.0485 d⁻¹
Step 3: Calculate the amount of P, given the initial amount (P₀) is 37.6 mg and the time elapsed (t) is 35.0 days
For first-order kinetics, we will use the following expression.
ln P = ln P₀ - k × t
ln P = ln 37.6 mg - 0.0485 d⁻¹ × 35.0 d
P = 6.88 mg
Answer:
The conservation of energy principle states that energy can neither be destroyed nor created. Instead, energy just transforms from one form into another. So what exactly is energy transformation? Well, as you might guess, energy transformation is defined as the process of changing energy from one form to another. There are so many different kinds of energy that can transform from one form to another. There is energy from chemical reactions called chemical energy, energy from thermal processes called heat energy, and energy from charged particles called electrical energy. The processes of fission, which is splitting atoms, and fusion, which is combining atoms, give us another type of energy called nuclear energy. And finally, the energy of motion, kinetic energy, and the energy associated with position, potential energy, are collectively called mechanical energy. That sounds like quite a lot, doesn't it? Well it is, but don't worry, it's actually all pretty easy to remember. Next, we'll explore all of these kinds of possible transformations in more detail. Different Types of Energy Transformations Chemical energy is the energy stored within a substance through the bonds of chemical compounds. The energy stored in these chemical bonds can be released and transformed during any type of chemical reaction. Think of when you're hungry. When you eat a piece of bread to satisfy this hunger, your body breaks down the chemical bonds of the bread and uses it to supply energy to your body. In this process, the chemical energy is transformed into mechanical energy, which you use to move, and which we'll cover in more detail in a moment. It also transforms it into thermal energy, which is created through the metabolic processes in your body to generate heat. Most of the time, chemical energy is released in the form of heat, and this transformation from chemical energy to heat, or thermal energy, is called an exothermic reaction. Next, there are two main types of mechanical energy: kinetic energy and potential energy. Kinetic energy is the energy associated with the motion of an object. Therefore, any object that moves has kinetic energy. Likewise, there are two types of potential energy: gravitational potential energy and elastic potential energy. Gravitational potential energy is associated with the energy stored by an object because of its location above the ground. Elastic potential energy is the energy stored by any object that can stretch or compress. Potential energy can be converted to kinetic energy and vice versa. For example, when you do a death-defying bungee jump off of a bridge, you are executing a variety of energy transformations. First, as you prepare to jump, you have gravitational potential energy - the bungee cord is slack so there is no elastic potential energy. Once you jump, you convert this gravitational potential energy into kinetic energy as you fall down. At the same time, the bungee cord begins to stretch out. As the cord stretches, it begins to store elastic potential energy. You stop at the very bottom when the cord is fully stretched out, so at this point, you have elastic potential energy. The cord then whips you back up, thereby converting the stored elastic potential energy into kinetic energy and gravitational potential energy. The process then repeats
Explanation:
here u go :P
Answer:
D: Electromagnetic
Explanation:
Chemical energy is the energy in chemical bonds which is a type of potential energy, eliminating both B and C. While kinetic energy is the energy of motion, photons are a wave/ particle so thinking it would have kinetic energy wouldn't be your fault but light is on the electromagnetic spectrum making D the most likely answer.
Three resonance structures can be drawn for the allyl cation while two resonance structures can be drawn for the amidate ion.
Sometimes, we cannot fully describe the bonding in a chemical specie using a single chemical structure. In such cases, we have to use a number of structures which cooperatively represent the actual bonding in the molecule. These structures are called resonance or canonical structures.
The resonance structures of the allyl cation and the amidate ion are shown in the images attached to this answer. These structures show the different bonding extremes in these organic ions.
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