Question 1:
Which of the following is the correct way to balance the chemical equation: H2 + O2 → H2O?
Explanation: The correct answer is B) 2H2 + O2 → 2H2O. Balancing the equation requires two molecules of hydrogen gas (H2) and one molecule of oxygen gas (O2) to form two molecules of water (H2O).
Question 2:
What coefficient should be placed in front of H2SO4 in the following equation to balance it: Al + H2SO4 → Al2(SO4)3 + H2?
Explanation: The correct answer is C) 3. Balancing the equation requires three molecules of sulfuric acid (H2SO4) to react with two atoms of aluminum (Al) to form one molecule of aluminum sulfate (Al2(SO4)3) and three molecules of hydrogen gas (H2).
Question 3:
Which of the following is the balanced chemical equation for the reaction between potassium permanganate (KMnO4) and hydrogen peroxide (H2O2) in acidic solution?
Explanation: The correct answer is A) 2KMnO4 + H2O2 → 2KOH + 2MnO2 + 3H2O + O2. This equation is balanced, with two molecules of potassium permanganate (KMnO4) and one molecule of hydrogen peroxide (H2O2) reacting to form two molecules of potassium hydroxide (KOH), two molecules of manganese dioxide (MnO2), three molecules of water (H2O), and one molecule of oxygen gas (O2).
Question 4:
Which of the following is the correctly balanced chemical equation for the combustion of methane (CH4) in oxygen (O2) to form carbon dioxide (CO2) and water (H2O)?
Explanation: The correct answer is B) CH4 + 2O2 → CO2 + 2H2O. This equation is balanced, with one molecule of methane (CH4) reacting with two molecules of oxygen (O2) to form one molecule of carbon dioxide (CO2) and two molecules of water (H2O).
Question 5:
What is the balanced chemical equation for the reaction between potassium hydroxide (KOH) and sulfuric acid (H2SO4) to form potassium sulfate (K2SO4) and water (H2O)?
Explanation: The correct answer is A) KOH + H2SO4 → K2SO4 + H2O. This equation is balanced, with one molecule of potassium hydroxide (KOH) reacting with one molecule of sulfuric acid (H2SO4) to form one molecule of potassium sulfate (K2SO4) and one molecule of water (H2O).