If all the teams in the class received a sample of the same mixture, each team will not obtain the same result for its % composition. Give two main types of reasons.

Alarge marble is dropped in a graduated cylinder with 35ml of water in it. the water level increases to 49ml. what is the volume of the marble

13. a covalent bond between two atoms is likely to be polar if: a. one of the atoms is much more electronegative than the other. b. the two atoms are equally electronegative. c. the two atoms are of the same element. d. the bond is part of a tetrahedrally shaped molecule. e. one atom is an anion.

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.