a student mixed 4.00g of zinc (mm=65.4) with 8.00g ofsulphuric acid (mm=98) **mm
ID: 683768 • Letter: A
Question
a student mixed 4.00g of zinc (mm=65.4) with 8.00g ofsulphuric acid (mm=98) **mm=molar mass** a)how many grams of hydrogen gas will be produced? b)which reactant is the limiting reactant? c)how many grams of excess reactant remain? Its been years since I've taken a chemistry course and Ireally dont even know where to start with this question. Anyhelp would be greatly appreciated!!! a student mixed 4.00g of zinc (mm=65.4) with 8.00g ofsulphuric acid (mm=98) **mm=molar mass** a)how many grams of hydrogen gas will be produced? b)which reactant is the limiting reactant? c)how many grams of excess reactant remain? Its been years since I've taken a chemistry course and Ireally dont even know where to start with this question. Anyhelp would be greatly appreciated!!!Explanation / Answer
The limiting reagent, LR, is the one that is NOT in excess,therefore, it controls how much product can theoretically beproduced. Whichever one of the starting materials (SM) is less (inmols) relative to the other is limiting. Start by writing out the balanced chemical eqtn. Make sure itis balanced: Zn + H2SO4 --> ZnSO4 + H2(g) this one was easy.. Now find the mols of both SMs and then divide by their molarcoefficient, both 1 in this case. Zn: 4/65.4=0.061 H2SO4: 8/98 = 0.082 So Zn is limiting. You can find the grams of either product produced by using theLR and by going through the molar ratio (the coefficients): (4g/65.4g/mol) (1molH2/1molZn) (2.02H2/1molH2), wher 2.02 isMW of H2(g). The units cancel and you are left in g H2. All the Zn will be used up, so there will be xs sulphuricacid. Find it by reversing the idea that I showed you above.. Hope that helps.Related Questions
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