Niobium-91 has a half-life of 680 years. After 2,040 years, how much niobium-91 will remain from a 300.0-g sample?

3 g

18.75 g

37.5 g

100.0 g

Draw the alkyne formed when 3,4-dichloroheptane is treated with an excess of strong base such as sodium amide

What is the difference between intensive & extensive phyiscal properties?

Which object will have the most kinetic energy?

Nitrogen makes up 78.08% of the volume of Earth's atmosphere, and oxygen makes up 20.95% of the volume. The total air pressure at sea level is 101.3 kPa. From this information, what can be calculated? A.

What is the remaining concentration of the cation that precipitates first, when the other cation just begins to precipitate? consider a solution that is 2.3*10-2 m in fe2 + and 2.0*10-2 m in mg2+?

How many moles of co2 could fit in a 475 ml bag at - 22c and 1.125 atm?

How mant atoms are in 3N2

The type of nuclear decay an unstable nucleus will undergo depends on its ratio of neutrons to protons. The radioisotope cobalt-65 has a ratio of neutrons to protons of 1.41, which is too high for a nucleus of this size.

1.87 $/gal to dollars per liter, Express your answer using three significant figures.

What can a student do to increase the force of attraction of a magnet on an iron block?