4. A student was not sure that she accurately recorded the final temperature of her melting point sample. Therefore, she decided to rerun the experiment with the same sample. Was this a wise decision

Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.

Which of the following is an indication that a substance has undergone a chemical change? a. no new product has been formed. b. the color of the substance has not changed. c. the original constitute has not changed. d. the molecular structure has changed.

Use the periodic table to find the molar mass of each element. molar mass h = g/mol molar mass s = g/mol molar mass o = g/mol