Nokea
Which of the following could be an empirical formula?
- A. C4H8
- B. C2H6
- C. CH
- D. C3H6
Correct Answer: C
Rationale: An empirical formula represents the simplest whole-number ratio of atoms in a compound. For a hydrocarbon compound consisting of carbon and hydrogen, the empirical formula should have the simplest ratio of carbon to hydrogen. Choice C, 'CH,' is the correct empirical formula as it represents a 1:1 ratio of carbon to hydrogen atoms, indicating the simplest ratio. Choices A, B, and D have multiple atoms of carbon and hydrogen, which do not represent the simplest whole-number ratio. Therefore, 'CH' is the empirical formula that best fits the definition.
You may also like to solve these questions
In a double replacement reaction, which of the following occurs?
- A. Energy in the form of heat or light is not always produced.
- B. The reactants can involve a variety of elements.
- C. A gas, solid precipitate, or compound forms in the exchange of ions.
- D. All of the above.
Correct Answer: C
Rationale: In a double replacement reaction, two compounds exchange ions to form two new compounds. This often results in the formation of a gas, a solid precipitate, or a new compound. Choice A is not always true as energy production can vary in different reactions. Choice B is not a defining characteristic of double replacement reactions, as the reactants can involve a variety of elements. Therefore, the correct answer is C, as it accurately describes a common outcome of double replacement reactions.
How are chemical equations typically written?
- A. Products → Reactants
- B. Reactants → Products
- C. Reactants + Reactants
- D. Products + Reactants
Correct Answer: B
Rationale: Chemical equations are typically written with reactants listed on the left side of the arrow and products on the right side. This convention signifies the progression of reactants transforming into products during a chemical reaction. Therefore, the correct way chemical equations are typically written is 'Reactants Ć’ Products.'
An atom has a mass of 16 and 6 protons. What element is it, and how many neutrons are there?
- A. Sulfur, 10
- B. Sulfur, 22
- C. Carbon, 10
- D. Carbon, 22
Correct Answer: C
Rationale: The atomic mass of an atom is the sum of its protons and neutrons. In this case, the atom has 6 protons. To find the number of neutrons, subtract the number of protons (6) from the atomic mass (16), resulting in 10 neutrons. Since the atom with 6 protons corresponds to Carbon (which has an atomic number of 6), the correct answer is Carbon, 10.
Which type of reaction is most likely represented by the products CO2 + H2O: CO2 + H2O?
- A. Synthesis
- B. Decomposition
- C. Single replacement
- D. Combustion
Correct Answer: D
Rationale: The reaction products CO2 and H2O suggest a combustion reaction. In a combustion reaction, a substance reacts with oxygen gas (O2) to produce carbon dioxide (CO2) and water (H2O) as products. The given reaction matches the characteristic products of a combustion reaction, indicating that option D, 'Combustion,' is the correct answer.
What type of reaction is represented by the equation KCl → K + Cl₂?
- A. Synthesis
- B. Decomposition
- C. Single replacement
- D. Double replacement
Correct Answer: B
Rationale: The reaction KCl → K + Cl2 is an example of a decomposition reaction. In a decomposition reaction, a compound breaks down into its constituent elements or simpler compounds. In this case, potassium chloride (KCl) decomposes into potassium (K) and chlorine gas (Cl2). Therefore, the correct answer is B, Decomposition.