If you measure the properties of an unknown material and find that 36.1 g (+/- 1.0 g) dissolve in 100 g of water and the material boils at 1415 °C ( +/- 5 ºC), which material would it most likely be? A) Potassium iodide
B) Sulfur
C) Lead nitrate
D) Iodine
E) Copper chloride
F) Sodium chloride
G) Copper nitrate

Explain why electric current cannot exist if a current doesn't have a voltage source.

Two masses are connected by a rope that hangs over a pulley as shown below. the pulley is a uniform cylinder of radius 푅=0.381meters and mass 푀=3.1푘푔. initially 푚"is on the ground and 푚#rests 2.5 meters above the ground. if the system is released, use conservation of energy to determine the speed of 푚#just before it strikes the ground. assume the pulley bearing is frictionless.

The starship enterprise is caught in a time warp and spock is forced to use the primitive techniques of the 20th century to determine the specific heat capacity of an unknown mineral. the 125-g sample was heated to 96.3°c and placed into a calorimeter containing 85.9 g of water at 20.0°c. the heat capacity of the calorimeter was 14.2 j/k. the final temperature in the calorimeter was 24.5°c. what is the specific heat capacity (in j/g°c) of the mineral? enter to 4 decimal places.