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WorksheetsPRE-UPS 2.0 DK014 SESSION 2020/2021
Total questions: 20
Worksheet time: 31mins
1. Aluminium reacted with bromine gas to produce aluminium bromide, AlBr3. The following statements are true EXCEPT
2Al(s) + 3Br2(g) → 2AlBr3 (s)
2g of Al reacted with 3g Br2 gas.
2 mol of Al reacted with 3 mol of Br2 gas.
2 mol of Al produced 2 mol 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
A sample of 50.0 ml of phosphoric acid is titrated with 25.0 ml 0.10 M sodium hydroxide solution. The reaction is as follows:
H3PO4(aq) + 2NaOH(aq) → Na3PO4(aq) + 3H2O(l)
0.017 M
0.025 M
1.50 M
2.50 M
You need 2 pieces of bread, 1 tablespoon of peanut butter and 2 tablespoons of strawberry jelly to make a sandwich. If you have 10 pieces of bread, 4 tablespoons of peanut butter and 15 tablespoons of jelly, what is the limiting reactant?
Bread
Peanut butter
Strawberry jelly
In a lab, a scientist calculated that he should produce 12.3 grams of product in his experiment. When he is finished collecting his product, it weighs 10.1 grams. What is his percentage yield?
82.1%
22.1%
18.7%
12.8%
The oxidation number of chlorine in HClO4 is:
+3
+1
+7
+5
Pentane (C5H12), burns in air to produce carbon dioxide and water.
_C5H12 + _O2 → _CO2 + _H2O
The coefficient of oxygen in the balanced equation is
7
8
9
10
How many grams of FeS are formed from 7.62g of Fe reacted with excess S ?
3.82 g
12.0 g
7.62 g
11.0 g
As₄S₄ + 4 O₂ → 4 SO₂ + 4 As
How many grams of sulfur dioxide, SO₂, are produced from 29.2 L of oxygen gas, O₂ at STP?
41.7 g
4.19 x 10⁴ g
2.09 x 10⁴ g
83.5 g
C₅H₁₁OH + 8 O₂ → 6 H₂O + 5 CO₂
How many grams of oxygen gas, O₂, are needed to make 4.05 g of carbon dioxide, CO₂, if the percent yield is 53.2% ?
1.72 x 10⁴ g
3.46 g
8.86 g
12.2 g
Which of the following half reactions correctly represents a reduction half reaction?
Fe →Fe2+ + 2e-
2O2-→O2 + 4e-
Pb4+ + 2e- →Pb2+
Fe + 3e- →Fe3+
Which of the following statements regarding electronic orbitals is/are correct?
Each p-orbital can hold a maximum of six electrons.
The three 3p-orbitals have different energy levels.
The 3p-orbitals have a higher energy level than the 3s-orbital.
The 1s-orbital has the same size and shape as the 2s-orbital.
The number of electrons in the 3d orbital of the atom of atomic number 27 is
9
7
6
6
Which one of the following contains no unpaired electrons in the ground state?
Be
Si
F
N
Which one of the following is the maximum number of atomic orbitals having a principal quantum number of two?
5
9
4
3
What is the electron configuration of As³⁻ ?
1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁴
1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶
1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p¹
1s²2s²2p⁶3s²3p⁶3d¹⁰
Identify the rule that is being violated
Aufbau principle
Hund's rule
Pauli's exclusion principle
Heisenberg uncertainty principle
The valence electron of a sodium atom (11N) in the ground state can have the quantum numbers (n, l, m, s)
(3,0,0,−1/2)
(2,0,0,−1/2)
(2,1,1,−1/2)
(2,0,1,−1/2)
All of the following species have the same number of electrons except
F
Ne
Na+
Al3+
What is the maximum number of electrons that can be accommodated in the third shell of an atom ?
6
10
18
32
An atom of element X has the same number of electrons as Fe2+ ion. Which of the following statement is/are true?
i. The electron configuration of element X is 1s2 2s2 2p6 3s2 3p6 3d4 4s2.
ii. Element X is a transition element.
iii. The electron configuration of X3+ ion is 1s2 2s2 2p6 3s2 3p6 3d3
i only is correct
i and ii only are correct
ii and iii only are correct
i, ii and iii are correct
