Which statement is true about the elements present in a pure substance?
2 answers:
Answer: Option (D) is the correct answer.
Explanation:
An element is defined as a substance that contains atoms of one type.
For example, a piece of sodium metal will contain only atoms of sodium.
Therefore, it is a pure substance. Whereas a compound is a substance that consists of two or more different atoms in similar composition.
For example, is a compound.
When elements change into compounds then they tend to change their chemical properties.
Hence, we can conclude that the statement they can only be separated by chemical methods, is true about the elements present in a pure substance.
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Answer: 69.72 kg of cryolite will be produced.
Explanation:
The balanced chemical equation is:
To calculate the moles, we use the equation:
moles of =
moles of =
moles of =
As 1 mole of reacts with 6 moles of
166 moles of reacts with =
moles of
As 1 mole of reacts with 12 moles of
166 moles of reacts with =
moles of
Thus is the limiting reagent.
As 1 mole of produces = 2 moles of cryolite
166 moles of reacts with =
moles of cryolite
Mass of cryolite =
Thus 69.72 kg of cryolite will be produced.