Go to the Quizzes Page Balancing Chemical Equations 0% 15 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 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. Impossible to determine without knowing the amount of oxygen used. More than 5 grams. Exactly 5 grams. 2 / 20 Which statement best describes the law of conservation of energy? The total energy absorbed and released from a chemical reaction varies. Energy can't be transferred between the system and the surroundings. The total energy absorbed and released from a chemical reaction stays the same. The amount of energy released by a system must be more than that absorbed by the surrounding. 3 / 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 4 / 20 What are the missing coefficients for the chemical equation below? P + O2 → P2O5 2 , 5 , 4 2 , 2 , 5 1 , 3 , 4 4 , 5 , 2 5 / 20 In a closed system undergoing a chemical reaction, the total mass of the reactants must be: Greater than the total mass of the products. Less than the total mass of the products. Unrelated to the total mass of the products. Equal to the total mass of the products. 6 / 20 In the unbalanced equation: Fe + O2 → FeO3 how many Fe atoms are on the reactant side? 2 1 It depends on the amount of Fe used There is no Fe in the equation 7 / 20 What are the missing coefficients for the chemical equation below? Ag2O → Ag + O2 2 , 4 , 1 5 , 4 , 2 1 , 2 , 3 2 , 2 , 2 8 / 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 9 / 20 What does balancing a chemical equation mean? Changing the names of the reactants and products Replacing elements with different ones Making sure the number of atoms of each element is the same on both sides of the reaction arrow Adding heat to a reaction 10 / 20 Why is it important to balance a chemical equation? To identify the reactants and products To make the equation look neat To calculate the rate of reaction To represent the Law of Conservation of Mass 11 / 20 What is the coefficient needed in front of O2 to balance the following equation? CH4 + O2 → CO2 + 2H2O 2 1 4 3 12 / 20 When balancing an equation, you can change the subscripts in the chemical formulas. True False 13 / 20 Which of the following equations is balanced? H2 + O2 → H2O Fe + 2HCl → FeCl2 + H 2Na + 2Cl2 → 2NaCl C3H8 + 5O2 → 3CO2 + 4H2O 14 / 20 A chemical reaction happens when ___________. existing bonds break and the atoms rearrange to form new bonds new bonds are formed to create complex compounds new atoms are created in the products existing atoms in the reactants are destroyed 15 / 20 What is the Law of Conservation of Mass? The total energy absorbed and released from a chemical reaction varies. 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. 16 / 20 What is the balanced equation for the reaction between methane (CH4) and oxygen (O2) to produce carbon dioxide (CO2) and water (H2O)? CH4 + O2 → CO2 + H2O CH4 + 2O2 → CO2 + 2H2O CH4 + O2 → CO2 + 2H2O CH4 + 2O2 → 2CO2 + H2O 17 / 20 What is the coefficient in a balanced chemical equation? A small number written behind a chemical formula An element on the right side of the equation A large number written in front of a chemical formula An element on the left side of the equation 18 / 20 When balancing the equation Fe + S → FeS, what coefficient is needed in front of FeS? 1 2 3 It cannot be balanced. 19 / 20 In the balanced equation N₂ + 3H₂ → 2NH₃, how many atoms of hydrogen (H) are on the reactant side? 6 2 4 3 20 / 20 In the balanced equation 2H₂ + O₂ → 2H₂O, what is the coefficient of hydrogen (H) on the product side? 3 2 4 1 Your score is 0% Restart quiz Go to the Quizzes Page