GRADE A Q&A
What is the empirical formula for hydrogen peroxide?
Molecular formula?
Structural formula? - (CORRECT ANSWER)HO
H2O2
H-O-O-H
Molecular and structural formula for acetic acid? - (CORRECT ANSWER)C2H4O2
What is the mole ratio of this reaction?
C8H18 > CO2 - (CORRECT ANSWER)1:8
1mol C8H18 > 8 mol CO2
Mole ratio of Mg(OH)2 to MgN2? - (CORRECT ANSWER)1:3
There is 1g of MgNH4PO4 x 6H2O in a sample of fertilizer.
Molar mass of MgNH4PO4 x 6H2O =245.42g/mol
Molar mass of P2O5 = 141.948g/mol
What is the equivalent mass of P2O5 in the sample? - (CORRECT ANSWER)1g/
(245.42g/mol) = 0.0041 mol MgNH4PO4 x 6H2O
equivalent mass of p2o5 = 1/2 (0.0041mol)(141.948 g/mol)
=0.289g P2O5
half because there is only 1 O in MgNH4PO4... but there are 2 of them in P2O5
meaning you would need half of it to match up with the mgnh...
1mol of = 6.02214x10^23 atoms . how many atoms in 3.32 x 10^-24 mol? -
(CORRECT ANSWER)3.32 x 10^-24 mol / 6.02214x10^23 = 2 ATOMS
balance this equation :
Al + KOH +H2O > K+(aq) + Al (OH)4^- + H2 - (CORRECT ANSWER)2 Al + 2 KOH
+6H2O > 2K+(aq) + 2Al (OH)4^- + 3H2
Atomic mass of Al = 26.98154g/mol. Can you have 5 x 10^-25 g of Al? - (CORRECT
ANSWER)(26.98154g/mol) / (6.02 x 10^23 atoms/mol) = 4.48x10^23g/atom.
No because 5.0x10^-25 is less than 4.48 x 10^23g.
Assume that you carry out the following dilutions
i) you take 1mL of 10^-6M of AsCl3 and diluted it to 1 Kiloleter (Solution A)
(ii) Then you take 1microliter of Solution A and dilute to 10L to make solution B
(iii) Then you take 1mL of Solution B and dilute to 1L to make Solution C.
Calculate the conc in solution c - (CORRECT ANSWER)CfVf = CiVi
What is the empirical formula for hydrogen peroxide?
Molecular formula?
Structural formula? - (CORRECT ANSWER)HO
H2O2
H-O-O-H
Molecular and structural formula for acetic acid? - (CORRECT ANSWER)C2H4O2
What is the mole ratio of this reaction?
C8H18 > CO2 - (CORRECT ANSWER)1:8
1mol C8H18 > 8 mol CO2
Mole ratio of Mg(OH)2 to MgN2? - (CORRECT ANSWER)1:3
There is 1g of MgNH4PO4 x 6H2O in a sample of fertilizer.
Molar mass of MgNH4PO4 x 6H2O =245.42g/mol
Molar mass of P2O5 = 141.948g/mol
What is the equivalent mass of P2O5 in the sample? - (CORRECT ANSWER)1g/
(245.42g/mol) = 0.0041 mol MgNH4PO4 x 6H2O
equivalent mass of p2o5 = 1/2 (0.0041mol)(141.948 g/mol)
=0.289g P2O5
half because there is only 1 O in MgNH4PO4... but there are 2 of them in P2O5
meaning you would need half of it to match up with the mgnh...
1mol of = 6.02214x10^23 atoms . how many atoms in 3.32 x 10^-24 mol? -
(CORRECT ANSWER)3.32 x 10^-24 mol / 6.02214x10^23 = 2 ATOMS
balance this equation :
Al + KOH +H2O > K+(aq) + Al (OH)4^- + H2 - (CORRECT ANSWER)2 Al + 2 KOH
+6H2O > 2K+(aq) + 2Al (OH)4^- + 3H2
Atomic mass of Al = 26.98154g/mol. Can you have 5 x 10^-25 g of Al? - (CORRECT
ANSWER)(26.98154g/mol) / (6.02 x 10^23 atoms/mol) = 4.48x10^23g/atom.
No because 5.0x10^-25 is less than 4.48 x 10^23g.
Assume that you carry out the following dilutions
i) you take 1mL of 10^-6M of AsCl3 and diluted it to 1 Kiloleter (Solution A)
(ii) Then you take 1microliter of Solution A and dilute to 10L to make solution B
(iii) Then you take 1mL of Solution B and dilute to 1L to make Solution C.
Calculate the conc in solution c - (CORRECT ANSWER)CfVf = CiVi
