Explain the following examples in terms of physical or chemical changes: breaking a pencil in two; water freezing and forming ice;
frying an egg; burning wood; leaves turning color in the fall. Please
sure that your answer contains the terms physical properties,
change in state, and change in composition.

Inside a flashbulb, oxygen surrounds a thin coil of magnesium. when the flashbulb is set off, a chemical reaction takes place in which magnesium combines with oxygen to form magnesium oxide. which of the chemical equations matches the reaction above? a. mg + o2 mgo2 + energy b. 2mg + o mg2o + energy c. 2mg + o2 2mgo + energy d. mg + o mgo + energy

The comparison of the number of atoms in a copper coin the size of a penny with the number of people on earth is made to illustrate which of the following? a. that atoms are indivisible b. that atoms are very small c. that atoms are very large d. that in a copper penny, there is one atom for every person on earth

Which statement accurately represents the arrangement of electrons in bohr’s atomic model?