RHODES UNIVERSITY
DEPARTMENT OF CHEMISTRY
MARCH 2024 MCQ CHEMISTRY 101
Examiners: Mrs J Sewry MARKS: 31
Prof K Lobb
MULTIPLE CHOICE – Attempt ALL questions – 40 minutes
Instructions
1. Write your student number under Student number on the answer form
2. In each column under your student number, fill in the circle containing the digit corresponding to
the digit in your student number above.
3. Task number: 87
4. Select your answer to each question and, with a dark pencil, or a black or blue pen, colour in the
circle containing the letter of that answer in the row corresponding to the question number.
5. Only one circle per row can be filled in.
6. If you make a mistake, cross it out and fill in another circle.
SECTION A – 39 QUESTIONS – 60 MINUTES
1. A sample of magnesium is burned in oxygen to form magnesium oxide. What mass of oxygen
is consumed if 74.62 g magnesium oxide is formed from 45.00 g magnesium? (2 marks)
(A) 0.60 g (B) 29.62 g (C) 119.62 g
(D) 3358.06 g (E) none of the above.
2. In addition to mass, which property of matter must be known to calculate its volume?
(A) molecular weight (B) pressure (C) specific heat
(D) temperature (E) density
3. A sample of cesium carbonate, weighing 3.80 g, requires 1.90 g of hydrogen bromide gas to
completely decompose to water, cesium bromide, and carbon dioxide gas. The total mass of
water and cesium bromide formed is 5.20 g and no hydrogen bromide or cesium carbonate
remains. According to the law of conservation of mass, what mass of carbon dioxide must have
been formed? (2 marks)
(A) 10.90 g (B) 5.49 g (C) 1.90 g
(D) 1.40 g (E) 0.50 g
4. Which of the following is an example of a chemical change?
(A) sodium chloride melting (B) alcohol boiling (C) sucrose dissolving
(D) iodine sublimating (E) silver tarnishing
, Chemistry 101
March 2024 MCQ
5. A student is working on converting a number that has a unit with the SI prefix milli- to a unit
that has the prefix mega-. Using your knowledge about the relative sizes that milli- and mega-
represent, how should the student convert the number?
(A) The student should use the number as is.
(B) The student should divide the number by 106.
(C) The student should multiply the number by 106.
(D) The student should divide the number by 109.
(E) The student should multiply the number by 109.
6. There are three isotopes of carbon differing with respect to
(A) number of neutrons. (B) nuclear charge. (C) number of protons.
(D) electron configuration. (E) atomic number.
7. Which of the following statements about different elements is INCORRECT?
(A) Helium is a noble gas. (B) Aluminum is a transition element.
(C) Potassium is an alkali metal. (D) Barium is an alkaline earth metal.
(E) Fluorine is a halogen.
8. What is the mass of carbon in grams found in one molecule of the compound C7H8O4?
(2 marks)
-23
(A) 1.34 x 10 g (B) 156.000000 g (C) 1.06 x 10-22 g
-22 21
(D) 1.4 x 10 g (E) 3.86 x 10 g
9. Which of the following compounds contains the largest number of atoms?
(2 marks)
(A) 2.0 mol of Na2SO4 (B) 1.0 mol of CH3COOH
(C) 5.0 mol of HBr (D) 3.0 mol of NO3
(E) 4.0 mol of H2S
10. 2H2S + SO2 → 3S + 2H2O
When 5 mol of H2S reacts with 3 mol of SO2, which statement applies?
(A) 2 mol of H2S remains. (B) 3 mol of water is formed.
(C) H2S is the limiting reactant. (D) SO2 is the limiting reagent.
(E) 3 mol of S is formed.
11. The molecular formula of a particular solid is C8H4O6. Its molecular mass is
(A) 296 amu (B) 170 amu (C) 100 amu (D) 288 amu (E) 196 amu.
12. A sample that cannot be separated into two or more substances by physical means is
(A) a compound. (B) a homogeneous mixture.
(C) a heterogeneous mixture. (D) an element.
(E) either a compound or an element.
Page 2 of 6
DEPARTMENT OF CHEMISTRY
MARCH 2024 MCQ CHEMISTRY 101
Examiners: Mrs J Sewry MARKS: 31
Prof K Lobb
MULTIPLE CHOICE – Attempt ALL questions – 40 minutes
Instructions
1. Write your student number under Student number on the answer form
2. In each column under your student number, fill in the circle containing the digit corresponding to
the digit in your student number above.
3. Task number: 87
4. Select your answer to each question and, with a dark pencil, or a black or blue pen, colour in the
circle containing the letter of that answer in the row corresponding to the question number.
5. Only one circle per row can be filled in.
6. If you make a mistake, cross it out and fill in another circle.
SECTION A – 39 QUESTIONS – 60 MINUTES
1. A sample of magnesium is burned in oxygen to form magnesium oxide. What mass of oxygen
is consumed if 74.62 g magnesium oxide is formed from 45.00 g magnesium? (2 marks)
(A) 0.60 g (B) 29.62 g (C) 119.62 g
(D) 3358.06 g (E) none of the above.
2. In addition to mass, which property of matter must be known to calculate its volume?
(A) molecular weight (B) pressure (C) specific heat
(D) temperature (E) density
3. A sample of cesium carbonate, weighing 3.80 g, requires 1.90 g of hydrogen bromide gas to
completely decompose to water, cesium bromide, and carbon dioxide gas. The total mass of
water and cesium bromide formed is 5.20 g and no hydrogen bromide or cesium carbonate
remains. According to the law of conservation of mass, what mass of carbon dioxide must have
been formed? (2 marks)
(A) 10.90 g (B) 5.49 g (C) 1.90 g
(D) 1.40 g (E) 0.50 g
4. Which of the following is an example of a chemical change?
(A) sodium chloride melting (B) alcohol boiling (C) sucrose dissolving
(D) iodine sublimating (E) silver tarnishing
, Chemistry 101
March 2024 MCQ
5. A student is working on converting a number that has a unit with the SI prefix milli- to a unit
that has the prefix mega-. Using your knowledge about the relative sizes that milli- and mega-
represent, how should the student convert the number?
(A) The student should use the number as is.
(B) The student should divide the number by 106.
(C) The student should multiply the number by 106.
(D) The student should divide the number by 109.
(E) The student should multiply the number by 109.
6. There are three isotopes of carbon differing with respect to
(A) number of neutrons. (B) nuclear charge. (C) number of protons.
(D) electron configuration. (E) atomic number.
7. Which of the following statements about different elements is INCORRECT?
(A) Helium is a noble gas. (B) Aluminum is a transition element.
(C) Potassium is an alkali metal. (D) Barium is an alkaline earth metal.
(E) Fluorine is a halogen.
8. What is the mass of carbon in grams found in one molecule of the compound C7H8O4?
(2 marks)
-23
(A) 1.34 x 10 g (B) 156.000000 g (C) 1.06 x 10-22 g
-22 21
(D) 1.4 x 10 g (E) 3.86 x 10 g
9. Which of the following compounds contains the largest number of atoms?
(2 marks)
(A) 2.0 mol of Na2SO4 (B) 1.0 mol of CH3COOH
(C) 5.0 mol of HBr (D) 3.0 mol of NO3
(E) 4.0 mol of H2S
10. 2H2S + SO2 → 3S + 2H2O
When 5 mol of H2S reacts with 3 mol of SO2, which statement applies?
(A) 2 mol of H2S remains. (B) 3 mol of water is formed.
(C) H2S is the limiting reactant. (D) SO2 is the limiting reagent.
(E) 3 mol of S is formed.
11. The molecular formula of a particular solid is C8H4O6. Its molecular mass is
(A) 296 amu (B) 170 amu (C) 100 amu (D) 288 amu (E) 196 amu.
12. A sample that cannot be separated into two or more substances by physical means is
(A) a compound. (B) a homogeneous mixture.
(C) a heterogeneous mixture. (D) an element.
(E) either a compound or an element.
Page 2 of 6
