According to ptolemy's model of the movement of celestial bodies, a. the sun is the center of the universe. b. the earth rotates around the sun. c. planets orbit in circular paths around the earth. d. the earth rotates around the moon.

6. using 3 – 4 sentences explain (in your own words) why water expands when it freezes? 7. using your knowledge of colligative properties explain whether sodium chloride or calcium chloride would be a more effective substance to melt the ice on a slick sidewalk. use 3 – 4 sentences in your explanation.

Predict the reactants of this chemical reaction. that is, fill in the left side of the chemical equation. be sure the equation you submit is balanced. (you can edit both sides of the equation to balance it, if you need to.) note: you are writing the molecular, and not the net ionic equation. > cacl2(aq) + h20(l)

Find the mass, in grams, of 5.00*10^23 molecules of f2