Identify the substance described by the following properties: Colorless, Refractive index = 1.309, Odorless, 10 degrees Celsius, Mass = 934 g, Hexagonal crystal structure, Volume 1000 mL, Tasteless, Low coefficient of friction, Sublimes, Both naturally-occurring & commercially produced

How many moles are in 250 grams of tungsten (w)? * 4.4x10^23 moles 4.2x10^23 moles 0.7 moles 1.4 moles

Agroup of students is studying convection currents. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other in an area with warm air. after 10 minutes, the balloons are released from a height of 1 meter. which of the following do the students most likely observe? a. the balloons both rise. the cold balloon is larger than the warm balloon. b. the balloons rise at the same rate. both balloons are the same size. c. the warm balloon expands and rises. the cold balloon shrinks and sinks. d. the cold balloon expands and rises. the warm balloon shrinks and sinks.

Which of the following is true about the speed of light? it depends on the wavelength.