Calcium chloride is used to make pickles. The calcium atom transfers electrons to chlorine atoms, leading to the formation of chemical bonds. Calcium chloride contains bonds.
a. covalent
b. ionic
c. metallic

Copper atoms are used to produce pennies. The copper atoms in pennies share many electrons. Pennies contain
bonds.
a. covalent
b. ionic
c. metallic

Hydrochloric acid is the main acid that helps break down food in the stomach. The atoms of hydrochloric acid share electrons. Hydrochloric acid contains
bonds.
a. covalent
b. ionic
c. metallic

Hot air balloons float in the air because of the difference in density between cold and hot air. in this problem, you will estimate the minimum temperature the gas inside the balloon needs to be, for it to take off. to do this, use the following variables and make these assumptions: the combined weight of the pilot basket together with that of the balloon fabric and other equipment is w. the volume of the hot air inside the balloon when it is inflated is v. the absolute temperature of the hot air at the bottom of the balloon is th (where th> tc). the absolute temperature of the cold air outside the balloon is tc and its density is ďc. the balloon is open at the bottom, so that the pressure inside and outside the balloon is the same. as always, treat air as an ideal gas. use g for the magnitude of the acceleration due to gravity.

Match the following vocabulary terms to their definitions. 1. amount of energy required to change 1 gram of material from the solid to the liquid state at its melting point 2. a measure of the kinetic energy of the particles of a substance 3. the amount of heat energy required to raise the temperature of 1 gram of liquid water from 14.5°c to 15.5°c 4. amount of energy required to change 1 gram of material from the liquid to the gaseous state at its boiling point 5. the amount of energy required to change 1 gram of a substance 1°c a. temperature b. latent heat of vaporization c. latent heat of fusion d. calorie e. specific heat

Which of these expressions are correct variations of the combined gas law? p1v1t2 = p2v2t1 both