A sample of 2.0×1010 atoms that decay by alpha emission has a half-life of 100 minmin. How many alpha particles are emitted between t=50mint=50min and t=200mint=200min ?

Which set of characteristics best describes igneous rock? a) largest type of rock, made of organic matter, hardest type of rock b) least abundant type of rock, made of other rocks, made mostly of minerals c) found on all continents, contains wavy bands of stripes, contains fossils d) most abundant type in earth's crust, made of magma/lava, contains no fossils

Define the kinetic molecular theory

Chemistry worksheet - i am not sure what they are asking for exactly?