Also, how do you know the chemical symbol for ions like Aluminum, barium, or sulfide ion? I know that they are Al^3+, Ba^2+ and S^2- but how do you get the superscripts?
Here is the method for every stoichiometry question: 1get a balanced formula (you got that)2Try to convert some part of the formula to moles (Al H2SO4 Al2(SO4)3 H23Then when you have it, you can find the amount of moles for all the ingridients.ingredientsnvert moles to whatever you need.
By how many electrons the atom gains or loses when it forms the ion Eg Al is electron structure 2.8.3 so it loses three electrons to become a stable ion Al - (-3 ) Al3+ Sulphur is 2.8.6 so adds two electrons to become a stable ion S + (-2) S2-
First of all, balance the equation: 2 Al + 3 H?SO? → Al?(SO?)? + 3 H? If I directly solve the problem for you, you lose because you learn nothingSo, I will give you hints: [First of all, do you know dimensional analysis? If not, google it up or see link for example [1] ] b) Whats given? 6.71g AlWhats asked? X g H2SO4Now convert g Al to g H2SO4 via moles! 1 mole Al 26.98g Al 1 mole H2SO4 (1.008g H x 2) + (32.07g S) + (16.00g O x 4) 1 mole H2SO4 98.09g H2SO4 HINT: xg H2SO4 6.71g Al x ( 1 mole Al / g Al) x (3 mole H2SO4 / 2 mole Al) x ( _g H2SO4 / 1 mole H2SO4) g H2SO4 ( fill in the blanks ) If you still don't understand how to do this, mention it by editing your post c) Not too different than problem BKnow the plan: Convert given grams of Al to H2SO4Compare result with given value 12.95g H2SO4Example: If the calculated value is less, than excess of H2SO4 was used Also asked, 6.21g Al xg H2 So, use dimensional analysis, keeping in the mind the factors: 1 mole Al 26.98g Al 1 mole H2 (1.008g H x 2) 1 mole H2 2.016g H2 HINT: xg H2 6.21g Al x ( 1 mole Al / g Al) x ( 2 mole H2 / 1 mole Al) x ( _g H2 / 1 mole H2) g H2 ( fill in the blanks ) d) Again, same as problem 1Know dimensional analysis (aka how to connect like units and then multiply and divide them)What is given? 62.5g Al, 126.2g H2SO4What is asked? xg Al2(SO4)3 Plan: 1Find out which one is the limiting reactant(The limit reactant is the one that is completely used up)2Simply convert the limiting reactant, if its Al or H2SO4, to Al2(SO4)3.
