POST UTME SKYLINE UNIVERSITY 2018 Chemistry | Objective

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Question 1
A 2.5 g sample of a metal is heated in a crucible until it reaches a temperature of 1000°C. If the specific heat capacity of the metal is 0.1 J/g°C, what is the energy required to heat the metal?
A. 250 J
B. 500 J
C. 750 J
D. 1000 J
Question 2
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of combustion of 1.5 mol of C(s) to form CO2(g).
A. -589.25 kJ
B. -589.25 kJ/mol
C. -589.25 kJ
D. -589.25 kJ/mol
Question 3
The reaction 2Al(s) + 6HCl(aq) → 2AlCl3(aq) + 3H2(g) is an example of a redox reaction. What is the oxidation state of Al in the reac\tant and product?
A. 0
B. +3
C. -3
D. +1
Question 4
A 2.50 g sample of a metal carbonate is heated to produce a metal oxide and carbon dioxide gas. If the mass of the metal oxide produced is 1.75 g, calculate the percentage yield of the metal oxide.
A. 60%
B. 70%
C. 80%
D. 90%
Question 5
The reaction between sodium hydroxide and hydrochloric acid is a neutralization reaction. What is the products of this reaction?
A. NaCl + H2O
B. NaOH + HCl
C. NaCl + H2O + CO2
D. NaOH + HCl + CO2
Question 6
A 2.5 g sample of a polymer is dissolved in 50 mL of a solvent. If the density of the solution is 1.2 g/mL, what is the molar mass of the polymer?
A. 1000 g/mol
B. 2000 g/mol
C. 3000 g/mol
D. 4000 g/mol
Question 7
The reaction 2CH4(g) + 3O2(g) → 2CO2(g) + 4H2O(g) is an example of a combustion reaction. What is the limiting reac\tant if 1.5 mol of CH4 and 2.5 mol of O2 are present?
A. CH4
B. O2
C. Neither
D. Both
Question 8
A 0.500 L sample of a gas at 25°C and 1.00 atm is collected over water. If the vapor pressure of water at 25°C is 23.8 mmHg, calculate the partial pressure of the gas.
A. 760 mmHg
B. 736 mmHg
C. 712 mmHg
D. 688 mmHg
Question 9
A 2.5 L flask contains 0.5 mol of N2(g) at 25°C. Calculate the pressure of the gas.
A. 1.01 atm
B. 1.01 atm
C. 1.01 atm
D. 1.01 atm
Question 10
A solution of 2.0 g of glu\cose in 100 g of water has a boiling point elevation of 0.5°C. What is the molar mass of glu\cose?
A. 180 g/mol
B. 200 g/mol
C. 220 g/mol
D. 240 g/mol
Question 11
A sample of an ideal gas is heated from 300 K to 400 K at cons\tant volume. What is the ratio of the final pressure to the initial pressure?
A. 1:1
B. 1:2
C. 2:1
D. 3:1
Question 12
A 0.1 M solution of a weak acid, HA, has a pH of 3.50. What is the concentration of the acid in the solution?
A. 0.01 M
B. 0.1 M
C. 0.5 M
D. 1 M
Question 13
A sample of a solid salt, MX2, has a molar mass of 250 g/mol. If 3.75 g of the salt is dissolved in 150 mL of water, what is the concentration of the salt in the solution?
A. 0.1 M
B. 0.2 M
C. 0.3 M
D. 0.5 M
Question 14
A sample of a solid salt, MX2, has a molar mass of 200 g/mol. If 2.50 g of the salt is dissolved in 100 mL of water, what is the concentration of the salt in the solution?
A. 0.05 M
B. 0.1 M
C. 0.2 M
D. 0.5 M
Question 15
A metal M reacts with oxygen to form a basic oxide MO. The reaction is as follows: 4M + 3O2 → 2MO2. What is the oxidation number of M?
A. +2
B. +3
C. +4
D. +5

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