Help with a few easy chemistry problems?
any questions you answer will be greatly appreciated!
1 how many moles or argon are present in 100g of argon
2 how many moles of hydrogen atoms are present in 25g of water
3 balance this equation
FeS + HCl --> FeCl2 + H2S
Answer:
molar mass of argon = 39.99g
100g/39.99g/mol = 2.5 moles argon
molar mass of water = 18.02g
25.0g/18.02g = 1.39 moles water
(1.39 moles water)(2 mol hydrogen/1 mol water)
=
2.78 moles hydrogen
FeS + 2HCl --> FeCl2 + H2S
ethane = C2H6
Balanced equation is:
2C2H6 + 7O2 = 4CO2 + 6H20
according to the mole ratios, 3.5 moles of O2 are required for one mole of ethane (7/2 = 3.5)
Hope that clears things up a bit.
1. Based on the periodic table, the molar mass of argon is 39.948g/mol. Thus, to find moles of argon in 100g, divide 100 by 39.948:
(100g)/(39.948g/mol)=2.50mol Ar
2. Mole Hydrogen in water
you know that there are two moles of hydrogen in one mole of water, given that water is H20.
So first, convert grams to moles.
1 mole water = 18 g/mol
25g/(18g/mol) = 1.4 mol H20
1.4 mol H2O (2mol H / 1 mol H2O) = 2.8 mol hydrogen
3. Alright, to balance the equation, the trick is to have the correct number of atoms on each side of the equation. We find that the number of sulfur and iron is the same on the reactants and the products side. And we find that there is only one hydrogen and one chlorine on the reactant side but two of each element on the products side. So the trick is to multiply H and Cl by two.
Thus, FeS + 2HCL --> FeCl2 + H2S is the balanced equation.
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