The answer is hard to give without any information.
Answer:
No, ΔE does not always equal zero because it refers to the systems internal energy, which is affected by heat and work
Explanation:
According to the first law of thermodynamics, energy is neither created nor destroyed. This implies that the total energy of a system is always a constant.
So, according to the first law of thermodynamics we have that ΔE = q + w. This means that the value of ΔE depends on q (heat) and w(work). Hence ΔE is not always zero since it depends on the respective values of q and w.
Answer:
HF is the limiting reactant
Explanation:
The balanced equation for the reaction is given below:
SiO₂ + 4HF —> SiF₄ + 2H₂O
From the balanced equation above,
1 mole of SiO₂ reacted with 4 moles of HF.
Finally, we shall determine the limiting reactant. This can be obtained as illustrated below:
From the balanced equation above,
1 mole of SiO₂ reacted with 4 moles of HF.
Therefore, 7.5 moles of SiO₂ will react with = 7.5 × 4 = 30 moles of HF.
From the calculation made above, we can see clearly that it will take a higher amount (i.e 30 moles) of HF than what was given from the question (i.e 5 moles) to react completely with 7.5 moles of SiO₂.
Therefore, HF is the limiting reactant and SiO₂ is the excess reactant.
The mineral is Iron Sulphide. It is not a mixture, but a compound. A mixture is when two substances are together, but not chemically bonded. For example, if I add food colouring to water, I have made a mixture because the food colouring has not chemically bonded to the water. If I react Iron with Suphur, the resulting substance is a compound. The resulting mineral will not burn or be magnetic because the compound has different properties to the elements themselves. For example, chlorine gas is toxic and sodium reacts violently with water, but sodium chloride is table salt, nor toxic nor explosive.
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