Go to the Quizzes Page Balancing Chemical Equations 0% 315 Created by AbuBakrShalabi Click "Watch Now" to watch the video. Then, answer the following questions: Please write your name and email to receive your certificate. 1 / 20 What is the coefficient needed in front of O2 to balance the following equation? CH4 + O2 →   CO2 + 2H2O 4 1 3 2 2 / 20 What are the missing coefficients for the chemical equation below? P + O2 →  P2O5 4 , 5 , 2 2 , 5 , 4 1 , 3 , 4 2 , 2 , 5 3 / 20 What are the missing coefficients for the chemical equation below? Ag2O → Ag + O2 1 , 2 , 3 2 , 2 , 2 2 , 4 , 1 5 , 4 , 2 4 / 20 Which statement best describes the law of conservation of energy? The amount of energy released by a system must be more than that absorbed by the surrounding. Energy can't be transferred between the system and the surroundings. The total energy absorbed and released from a chemical reaction varies. The total energy absorbed and released from a chemical reaction stays the same. 5 / 20 When balancing an equation, you can: Change the chemical formulas of the reactants and products None of the above Change the coefficients in front of the formulas Add or remove atoms from the equation 6 / 20 Which of the following equations is balanced? C3H8 + 5O2 →  3CO2 + 4H2O 2Na + 2Cl2 →  2NaCl Fe + 2HCl →  FeCl2 + H H2 + O2 →  H2O 7 / 20 A chemical reaction happens when ___________. existing atoms in the reactants are destroyed existing bonds break and the atoms rearrange to form new bonds new atoms are created in the products new bonds are formed to create complex compounds 8 / 20 In the balanced equation 2H₂ + O₂ → 2H₂O, what is the coefficient of hydrogen (H) on the product side? 3 1 2 4 9 / 20 When balancing an equation, you can change the subscripts in the chemical formulas. False True 10 / 20 If 5 grams of magnesium (Mg) react with oxygen (O₂) to form magnesium oxide (MgO), the total mass of the magnesium oxide produced will be: Less than 5 grams. Exactly 5 grams. Impossible to determine without knowing the amount of oxygen used. More than 5 grams. 11 / 20 In a closed system undergoing a chemical reaction, the total mass of the reactants must be: Less than the total mass of the products. Greater than the total mass of the products. Unrelated to the total mass of the products. Equal to the total mass of the products. 12 / 20 Why is it important to balance a chemical equation? To represent the Law of Conservation of Mass To make the equation look neat To identify the reactants and products To calculate the rate of reaction 13 / 20 What is the Law of Conservation of Mass? The total charge of a system must remain constant. Energy can be neither created nor destroyed. Matter can be neither created nor destroyed in a chemical reaction. The total energy absorbed and released from a chemical reaction varies. 14 / 20 What is the balanced equation for the reaction between methane (CH4) and oxygen (O2) to produce carbon dioxide (CO2) and water (H2O)? CH4 + 2O2 → 2CO2 + H2O CH4 + O2 → CO2 + H2O CH4 + 2O2 → CO2 + 2H2O CH4 + O2 → CO2 + 2H2O 15 / 20 In the balanced equation N₂ + 3H₂ → 2NH₃, how many atoms of hydrogen (H) are on the reactant side? 3 6 4 2 16 / 20 In a balanced equation, the total number of atoms of each element must be the same on both sides of the reaction arrow. False True 17 / 20 In the unbalanced equation: Fe + O2 → FeO3 how many Fe atoms are on the reactant side? There is no Fe in the equation 2 It depends on the amount of Fe used 1 18 / 20 What does balancing a chemical equation mean? Changing the names of the reactants and products Adding heat to a reaction Replacing elements with different ones Making sure the number of atoms of each element is the same on both sides of the reaction arrow 19 / 20 When balancing the equation Fe + S →  FeS, what coefficient is needed in front of FeS? 2 1 3 It cannot be balanced. 20 / 20 What is the coefficient in a balanced chemical equation? An element on the left side of the equation An element on the right side of the equation A small number written behind a chemical formula A large number written in front of a chemical formula Your score is 0% Restart quiz Go to the Quizzes Page