BECE - Basic Education Certificate Examination Matter, Elements, and Compounds Questions and Answers 1 — Questions and Answers
Question 1: Which of the following substances is a compound?
- Air
- Water (Correct answer)
- Nitrogen
- Gold
Correct answer: Water
Water is a compound because it is formed from the chemical combination of two elements, hydrogen and oxygen, in a fixed ratio (H₂O). Air is a mixture of gases, while nitrogen and gold are elements.
Question 2: A student observes that a substance is made up of only one type of atom and cannot be broken down into simpler substances by chemical means. How should the student classify this substance?
- A mixture
- A compound
- An element (Correct answer)
- A solution
Correct answer: An element
An element is a pure substance consisting of only one type of atom, which cannot be broken down into a simpler type of matter by either physical or chemical means.
Question 3: In a science experiment, two clear liquids are physically mixed together. The resulting liquid is also clear, but its components can be separated by distillation. The original properties of the liquids are retained. This new substance is best described as a...
- Compound
- Mixture (Correct answer)
- Element
- Molecule
Correct answer: Mixture
The scenario describes a mixture. Key indicators are that the substances are physically mixed, not chemically combined; they can be separated by a physical means (distillation); and they retain their original properties.
Question 4: Which of the following correctly describes a key difference between a compound and a mixture?
- A compound has a variable composition, while a mixture has a fixed composition.
- The components of a compound can be separated by physical means, while those of a mixture cannot.
- Energy is always absorbed when a mixture is formed, but released when a compound is formed.
- A compound has properties different from its constituents, while a mixture retains the properties of its components. (Correct answer)
Correct answer: A compound has properties different from its constituents, while a mixture retains the properties of its components.
A defining characteristic of a compound is that it has new, unique properties that are different from the elements that formed it. In a mixture, the individual substances keep their own properties. For example, salt (a compound) is very different from its constituent elements, sodium and chlorine.
Question 5: Table salt has the chemical formula NaCl. This indicates that it is a compound made up of which two elements?
- Sodium and Carbon
- Nitrogen and Chlorine
- Sodium and Chlorine (Correct answer)
- Nitrogen and Carbon
Correct answer: Sodium and Chlorine
The chemical formula NaCl represents Sodium Chloride. 'Na' is the chemical symbol for the element Sodium, and 'Cl' is the chemical symbol for the element Chlorine.
Question 6: All of the following are examples of matter EXCEPT:
- A book
- Air
- Sunlight (Correct answer)
- Water
Correct answer: Sunlight
Matter is defined as anything that has mass and occupies space. A book, air, and water all have mass and take up space. Sunlight is a form of energy, which does not have mass or volume.
BECE - Basic Education Certificate Examination Matter, Elements, and Compounds Questions and Answers 1
Which of the following substances is a compound?