Label each of the following changes or properties as being a physical (P) or chemical (C) change or property. a. One cm^3 of water has a mass of one gram. b. Burning hydrogen in the presence of oxygen produces water. C. Candle wax will melt when heated gently. An iron nail left outside for a year will rust. e.To raise the temperature of 1 kg of lead by 1^circ C requires 130 joules of energy. f. If ice is heated enough,the ice will change to steam. Melting , boiling,and bending are considered physical changes, put burning is a chemical change . Explain why this is so. How may a substance be tested to determine whether or not t is an element? upply the missing number for each of the following. The number of naturally occurring elements. The atomic number of the heaviest element. The atomic number of the lightest element. The total number of elements identified (as of the publication of this book).

a. One cm³ of water has a mass of one gram. (P)<br />b. Burning hydrogen in the presence of oxygen produces water. (C)<br />c. Candle wax will melt when heated gently. (P)<br />d. An iron nail left outside for a year will rust. (C)<br />e. To raise the temperature of 1 kg of lead by 1°C requires 130 joules of energy. (P)<br />f. If ice is heated enough, the ice will change to steam. (P)<br /><br />Melting, boiling, and bending are considered physical changes because they do not alter the chemical composition of the substance. The molecules or atoms of the substance are rearranged, but the substance itself remains the same. On the other hand, burning is a chemical change because it involves a chemical reaction where the original substance is transformed into a new substance with different chemical properties.<br /><br />To determine whether a substance is an element, it can be tested by examining its chemical properties and behavior. Elements have unique chemical properties that distinguish them from compounds or mixtures. By analyzing the substance's chemical composition and its reactions with other substances, it can be determined whether it is an element or not.<br /><br />The number of naturally occurring elements: 92<br />The atomic number of the heaviest element: 118<br />The atomic number of the lightest element: 1<br />The total number of elements identified (as of the publication of this book): 118