What is the law that ensures that chemical reactions are balanced? First law of thermodynamics The law of conservation of energy The law of conservation of matter Law of definite composition Question 2 Balance the following chemical equation and give the coefficients: underline ( )C_(2)H_(4)+underline ( )O_(2)arrow underline ( )CO_(2)+underline ( )H_(2)O 2,2,1,2 1,3,2,2 2,3,1,3 1,2,1,2

Question 1:<br />The law that ensures that chemical reactions are balanced is the law of conservation of matter. This law states that matter cannot be created or destroyed in a chemical reaction, only rearranged. Therefore, the number of atoms of each element must be the same on both sides of a chemical equation.<br /><br />Answer: The law of conservation of matter<br /><br />Question 2:<br />To balance the chemical equation, we need to ensure that the number of atoms of each element is the same on both sides of the equation. <br /><br />Given equation: $C_{2}H_{4} + O_{2} \rightarrow CO_{2} + H_{2}O$<br /><br />To balance the equation, we need to find the coefficients that make the number of atoms of each element equal on both sides.<br /><br />The correct coefficients are: $1, 3, 2, 2$<br /><br />Balanced equation: $C_{2}H_{4} + 3O_{2} \rightarrow 2CO_{2} + 2H_{2}O$<br /><br />Answer: $1, 3, 2, 2$