A student reads a barometer in the laboratory and finds the prevailing atmospheric pressure to be 675 mm Hg. Express this pressure in atmospheres, kilopascals, torrs, pounds per square inch, and pascals. Hint: 1 atm = 101.3 kPa = 760 torr = 760 mm Hg = 14.69 psi 1.013x10 Pa mm Hg atm kPa torr psi Pa 675

Evaluate this exponential expression,8. (2 + 3)2 – 42

Why is the bond angle in a water molecule less than the bond angle of methane? a. the central oxygen atom in water has two lone pairs of electrons, whereas the central carbon atom in methane has no lone pairs. b. the central hydrogen atom in water has one lone pair of electrons, whereas the central carbon atom in methane has two lone pairs. c. the central oxygen atom in water has four lone pairs of electrons, whereas the central carbon atom in methane has only one lone pair. d. the central oxygen atom exerts more repulsive force on surrounding atoms than the central carbon atom in methane does. reset next

Observation and experimentation have led many scientists to accept a theory about the origin of the universe. this theory is called the big bang theory. scientific evidence collected and observed by scientists around the world suggests that the universe is ever expanding from a hot and dense initial state. what makes this a scientific theory? (2 points)