8. What coefficients will balance the following equation? underline ( )Al_(2)O_(3)+underline ( )F_(2)arrow underline ( )AlF_(3)+underline ( )O_(2) a. 1,6,43 b. 1,2,1,3 C. 2,6,43 d. 2,12,86 9. Iron and Dioxygen gas react to form Iron (III) oxide. Which of the following equations correctly balances the reaction described? a. Fe+O_(2)arrow Fe_(2)O_(3) b. 4Fe+3O_(2)arrow 2Fe_(2)O_(3) C. Fe_(2)+O_(3)arrow Fe_(2)O_(3) d. 2Fe+3Oarrow Fe_(2)O_(3) 10. During a lab experiment, you observe several signs that a reaction has occurred. Which of the following is a sign that a chemical reaction has occurred? (Choose THREE correct answers) a. Gas was produced and bubbled out of the beaker b. The reactants were both liquid C. The beaker felt cold to the touch d. Formation of a yellow solid from two clear solutions 11. Aluminum chloride and Beryllium are produced when Aluminum is placed in Beryllium chloride. What is the balanced equation for this reaction? a. 2Al+6BeCl_(2)arrow 2AlCl_(3)+3Be b 2Al+3BeCl_(2)arrow 2AlCl_(3)+3Be C. Al+2BeClarrow AlCl_(2)+2Be Be+AlClarrow Al+BeCl 12. Which balanced equation represents a single replacement reaction? a. Mg+2AgNO_(3)arrow Mg(NO_(3))_(2)+2Ag b MgCl_(2)+2AgNO_(3)arrow 2AgCl+Mg(NO_(3))_(2) 2Mg+O_(2)arrow 2MgO MgCO_(3)arrow MgO+CO_(2) 13. Which of the following explanations justifies your selection for Question #13? a. one element replaced another in a compound, forming a new element and a new compound. b. two compounds switched elements, forming two new compounds. C. a single compound broke down into two or more simpler substances. d. two or more reactants combined to form a single product. 14. A balanced chemical equation reflects the idea that - (Choose TWO correct answers) a. the mass of the products is equal to the mass of the reactants. b. the number of atoms of each element is the same on both sides of the equation C. the mass of the products is greater than the mass of the reactants. d. the number of atoms of each element is different on both sides of the equation

8. The correct answer is b. 1,2,1,3. To balance the equation, we need to ensure that the number of atoms of each element is the same on both sides of the equation. In this case, we have 2 aluminum atoms on the left side and 2 aluminum atoms on the right side. We also have 3 fluorine atoms on the left side and 3 fluorine atoms on the right side. Finally, we have 3 oxygen atoms on the left side and 3 oxygen atoms on the right side. Therefore, the balanced equation is: Al2O3 + 2F2 → 2AlF3 + 3O2.<br /><br />9. The correct answer is b. 4Fe + 3O2 → 2Fe2O3. To balance the equation, we need to ensure that the number of atoms of each element is the same on both sides of the equation. In this case, we have 4 iron atoms on the left side and 4 iron atoms on the right side. We also have 6 oxygen atoms on the left side and 6 oxygen atoms on the right side. Therefore, the balanced equation is: 4Fe + 3O2 → 2Fe2O3.<br /><br />10. The correct answers are a, c, and d. Signs that a chemical reaction has occurred include the production of gas, a change in temperature, and the formation of a new substance. In this case, the production of gas (a), the beaker feeling cold to the touch (c), and the formation of a yellow solid from two clear solutions (d) are all signs that a chemical reaction has occurred.<br /><br />11. The correct answer is b. 2Al + 3BeCl2 → 2AlCl3 + 3Be. To balance the equation, we need to ensure that the number of atoms of each element is the same on both sides of the equation. In this case, we have 2 aluminum atoms on the left side and 2 aluminum atoms on the right side. We also have 3 beryllium atoms on the left side and 3 beryllium atoms on the right side. Finally, we have 6 chlorine atoms on the left side and 6 chlorine atoms on the right side. Therefore, the balanced equation is: 2Al + 3BeCl2 → 2AlCl3 + 3Be.<br /><br />12. The correct answer is a. Mg + 2AgNO3 → Mg(NO3)2 + 2Ag. A single replacement reaction occurs when one element replaces another element in a compound, forming a new element and a new compound. In this case, magnesium (Mg) replaces silver (Ag) in silver nitrate (AgNO3), forming magnesium nitrate (Mg(NO3)2) and silver (Ag).<br /><br />13. The correct answer is a. One element replaced another in a compound, forming a new element and a new compound. This explanation justifies the selection of option a in question 12, which describes a single replacement reaction.<br /><br />14. The correct answers are a and b. A balanced chemical equation reflects the idea that the mass of the products is equal to the mass of the reactants (a) and the number of atoms of each element is the same on both sides of the equation (b). This is based on the law of conservation of mass, which states that matter cannot be created or destroyed in a chemical reaction.