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WorksheetsPRE-UPS 2 (CHEMISTRY DK014)
Total questions: 20
Worksheet time: 10mins
The oxidation number of nitrogen in N2O and N2F4 are respectively
-2 and -3
-2 and +2
+1 and +2
+1 and -3
Hexane (C6H14) burns in air to produce carbon dioxide and water.
C6H14 + O2 → CO2 + H2O
The stoichiometry coefficient of oxygen in the balanced chemical equation is
17
18
19
20
Balanced the following chemical equation in acidic medium.
MnO4- + C2O42- → Mn2+ + CO2
The sum of stoichiometry coefficient is
25
29
33
43
A sample of 50.0 mL of phosphoric acid, H3PO4 is titrated with 25.0 mL 0.1 M of sodium hydroxide, NaOH solution. The reaction is as follows:
H3PO4 (aq) + 3NaOH (aq) → Na3PO4(aq) + 3H2O (l)
Calculate the molarity of phosphoric acid, H3PO4 needed to neutralise the 25.0 mL 0.1 M sodium hydroxide, NaOH.
0.017 M
0.67 M
1.5 M
6.0 M
Given the following equation
C5H12 + 8O2 → 5CO2 + 6H2O
Determine the excess reactant if 2 mole of C5H12 and 8 mole of O2 are allowed to react.
C5H12
O2
CO2
H2O
The ........... yield is the maximum amount of product possible in a reaction. This determines the amount of product that should be produced in a perfect setting.
Percentage
Actual
Stoichiometry
Theoretical
Given the following equation
4FeS2 + 11O2 → 2Fe2O3 + 8SO2
If 290 g of FeS2 is allowed to react with 180 g of O2, choose the CORRECT answer(s).
I. FeS2 is the limiting reactant.
II. O2 is the limiting reactant.
III. 1.023 mol Fe2O3 is produced.
I only
I and II
II and III
I, II and III
Ammonia burns in oxygen according to the equation below:
4NH3 + 3O2 → 2N2 + 6H2O
If 100 cm3 of ammonia is burnt in 100 cm3 of oxygen at STP, calculate the volume of oxygen gas remained after the reaction completed.
25 cm3
50 cm3
75 cm3
80 cm3
Aluminium, Al reacted with bromine gas, Br2 to produce aluminium bromide, AlBr3. The following statements are true EXCEPT
2Al + 3Br2 → 2AlBr3
2g of Al reacted with 3g of Br2 gas
2 mol of Al reacted with 3 mol of Br2 gas
2 mol of Al produce 2 mol of AlBr3
12.04 x 1023 Al atoms reacted with 18.12 x 1023 molecules of Br2 to produce 12.04 x 1023 formula unit of AlBr3
When potassium chlorate(V), KClO3 , is heated strongly, a mixture of potassium chlorate(VII), KClO4 and potassium chloride, KCl is produced.
4KClO3 → 3KClO4 + KCl
What is the amount of potassium chlorate(V), KClO3 must be used to produce 0.075 mol of potassium chlorate(VII), KClO4?
0.05 mol
0.10 mol
0.15 mol
0.20 mol
When excess of silver nitrate, AgNO3 was added to 25.0 cm3 of magnesium chloride solution, MgCl2, 2.87 g of silver chloride, AgCl was precipitated.
2AgNO3 + MgCl2 → 2AgCl + Mg(NO3)2
What is the concentration of magnesium chloride used in the reaction.
[RAM Ag: 108, Cl: 35.5]
0.1 M
0.2 M
0.4 M
0.8 M
Identify the reducing agent in this redox reaction
2NO2(g) + 7H2 → 2NH3 + 4H2O
H2
NO2
NH3
H2O
How many electrons can the first energy level hold?
2
6
10
18
Which of the following statements is true about the 3s and the 4s sublevels?
These sub-shell have the same energy
These sub-shell hold different amounts of electrons
These sub-shell are the same distance from the nucleus
These sub-shell have the same shape
Which of the following sets of four quantum number is not allowed?
(3, 2, +1, -1/2)
(4, 1, +2, +1/2)
(5, 3, -1, +1/2)
(7, 6, -5, -1/2)
Which of the following atoms have three unpaired electrons?
Boron
Carbon
Nitrogen
Oxygen
In the quantum mechanical model of an atom, an orbital is defined as a
3 dimensional region where high probability of protons can be found.
3 dimensional region where high probability of electrons can be found.
Circular path travelled by an electron around the nucleus.
Circular path travelled by a proton around the nucleus
The ___________ quantum number defines the shape of an orbital.
Magnetic
Electron spin
Angular momentum
Principal
How many quantum numbers are necessary to designate a particular electron in an atom?
3
4
2
1
There are _______ orbitals in the second shell.
1
2
4
8
