Which chemical symbol represents an element?
2 answers:
Answer:
Explanation:
Element is a pure substance which is composed of atoms of similar elements.
It can not be decomposed into simpler constituents using chemical reactions.Example: Nitrogen
Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.
It can be decomposed into simpler constituents using chemical reactions. Example: carbon dioxide , water
, carbon monoxide
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Answer : The mass of hydrogen gas consumed will be, 4.5 grams
Explanation : Given,
Mass of = 21 g
Mass of = 18 g
Molar mass of = 28 g/mole
Molar mass of = 2 g/mole
First we have to calculate the moles of and
.
Now we have to calculate the limiting and excess reagent.
The balanced chemical reaction is,
From the given balanced reaction, we conclude that
As, 1 mole of react with 3 moles of
So, 0.75 moles of react with
moles of
From this we conclude that, is an excess reagent because the given moles are greater than the required moles and
is a limiting reagent because it limits the formation of product.
The moles of hydrogen gas consumed = 2.25 mole
Now we have to calculate the mass of hydrogen gas consumed.
Therefore, the mass of hydrogen gas consumed will be, 4.5 grams