If an isotope of an element has 40 neutrons and a mass number of 79, how many electrons must it have?
1 answer:
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Answer:
is reduced in the reaction
Explanation:
The given reaction is
The oxidation number of is changed from
And The oxidation number of is changed from
Hence, is oxidized and
is reduced
Answer : The number of sodium ions is equal to the number of formula units of salt.
Explanation : In the given reaction of NaCl the statement which describes it the best is that the number of sodium ions is found to be same along with the formula units in the product side.
+
----> NaCl.
Its clear from the equation that one mole of Na and one mole of Cl combines together to give the product, which is one mole of NaCl. The number of ions on both the sides are equal.
Answer: Lithium
Explanation: The balanced chemical equation is:
It can be seen, 4 moles of lithium combines with 1 mole of oxygen gas to produce 2 moles of lithium oxide.
Thus 8.4 moles of lithium combines with=of oxygen gas to produce 4.2 moles of lithium oxide.
As, Lithium limits the formation of product, it is the limiting reagent and Oxygen gas is present in excess, it is called the excess reagent. (4.6-2.1)=2.5 moles of oxygen gas are present in excess.