Answer:
Uranium must be purified before it is used as a fuel source
Explanation:
The purer the uranium sample, the more the concentration of uranium in the fuel is.
Whenever uranium is extracted from nature, it contains a lot of impurities. Only a few special nuclear reactors can utilize uranium in this raw state. most of the others have to get uranium to become about 3% pure before they begin using it.
To do this, uranium has to be passed through a series of chemical reactions all with the aim of extracting the other compounds that may be present in the fuel.
The answer to the question is- Fe2O3
Answer:
- <u><em>It is positive when the bonds of the product store more energy than those of the reactants.</em></u>
Explanation:
The <em>standard enthalpy of formation</em>, <em>ΔHf</em>, is defined as the energy required to form 1 mole of a substance from its contituent elements under standard conditions of pressure and temperature.
Then, per defintion, when the elements are already at their standard states, there is not energy involved to form them from that very state; this is, the standard enthalpy of formation of the elements in their standard states is zero.
It is not zero for the compounds in its standard state, because energy should be released or absorbed to form the compounds from their consituent elements. Thus, the first choice is false.
When the bonds of the products store more energy than the those of the reactants, the difference is:
- ΔHf = ΔHf products - ΔHf reactants > 0, meaning that ΔHf is positive. Hence, the second statement is true.
Third is false because forming the compounds may require to use (absorb) or release (produce) energy, which means that ΔHf could be positive or negative.
Fourth statement is false, because the standard state of many elements is not liquid. For example, it is required to supply energy to iron to make it liquid. Thus, the enthalpy of formation of iron in liquid state is not zero.
Below are the choices that can be found from other sources:
<span>A) elements
B) ions
C) molecules
D) neutrons
the answer is ions.
</span>A Star<span> and hence our Sun, is an almost entirely ionized ball of </span>plasma<span>, consisting of electrons and ions, in which there is hardly any gas (neutral atoms). The movement of the </span>plasma<span> produces strong magnetic fields and corresponding electric currents.</span>
If two particles have the same charge they will repel each other when brought close together.