Nokea
How many water molecules are present in the products?
- A. 2
- B. 4
- C. 1
Correct Answer: A
Rationale: In chemical reactions, it is essential to balance the equation to determine the quantity of each molecule present in the products accurately. For this specific reaction, the balanced equation reveals that 2 water molecules are produced. When the reactants undergo the reaction, the products formed include 2 water molecules. Thus, the correct answer is A: 2.
You may also like to solve these questions
What is a combustion reaction?
- A. It absorbs heat.
- B. It involves the replacement of one element by another.
- C. It involves the sharing of electrons.
- D. It is a reaction that involves oxygen.
Correct Answer: D
Rationale: A combustion reaction is a chemical process that involves a substance reacting with oxygen to produce heat and light. The key component in a combustion reaction is oxygen, making choice D the correct answer. Combustion reactions are typically exothermic, releasing energy in the form of heat and light, making choice A incorrect. Choices B and C describe different types of chemical reactions, not combustion reactions. Therefore, the correct answer is D.
What is pH?
- A. The measure of concentration of H₃O⺠ions
- B. The measure of concentration of hydrogen ions
- C. The measure of concentration of Hâ‚‚O molecules
- D. None of the above
Correct Answer: A
Rationale: The correct answer is 'A: The measure of concentration of H₃O⺠ions.' pH is a measure of the concentration of hydronium ions (H₃Oâº) in a solution, indicating the acidity or alkalinity on a scale from 0 to 14. Values below 7 are acidic, 7 is neutral, and above 7 is alkaline/basic. Choice B is incorrect as pH specifically measures hydronium ions, not hydrogen atoms. Choice C refers to water (Hâ‚‚O), which is not directly related to pH measurement.
Which of the following statements is most accurate about chemical formulas?
- A. 2Hâ‚‚O has a total of 2 hydrogen atoms
- B. 2Hâ‚‚O represents two water molecules
- C. Hâ‚‚Oâ‚‚ represents two water molecules
- D. None of the above
Correct Answer: B
Rationale: The correct answer is 'B: 2Hâ‚‚O represents two water molecules.' The chemical formula for water is Hâ‚‚O, which consists of two hydrogen atoms and one oxygen atom per molecule. Therefore, when it is written as 2Hâ‚‚O, it indicates two water molecules. Option B accurately represents this, making it the most accurate statement among the choices.
An element has 6 protons, 6 electrons, and 6 neutrons. What is its atomic number?
- A. 6
- B. 12
- C. 18
- D. Not enough information
Correct Answer: A
Rationale: The atomic number of an element is determined by the number of protons in its nucleus. Since the element in question has 6 protons, its atomic number is also 6. The number of neutrons and electrons does not impact the atomic number, which is solely based on the number of protons. Therefore, the correct answer is A: 6.
The products of a reaction are CO2 and H2O. Which type of reaction is this most likely to be?
- A. Synthesis
- B. Decomposition
- C. Single replacement
- D. Combustion
Correct Answer: D
Rationale: The reaction products CO2 and H2O indicate the formation of carbon dioxide and water, which are typical products of a combustion reaction. Combustion reactions involve the rapid combination of a substance with oxygen, producing heat and light energy. In this case, the presence of CO2 and H2O suggests a combustion reaction where a hydrocarbon or organic compound has reacted with oxygen to form these products. Therefore, the correct answer is 'Combustion' (choice D) as it aligns with the formation of CO2 and H2O in this reaction scenario.