If 50% of radioactive element remains after 4000 years what what is the half life

During an effusion experiment, oxygen gas passed through a tiny hole 2.5 times faster than the same number of moles of another gas under the same conditions. What is the molar mass of the unknown gas? (Note: the molar mass of oxygen gas is 32.

Which statement best describes science? A) science can answer any and all questions B) science cannot answer questions about the natural world C) science cannot answer questions about what people should do D) science can answer only mathematical

Monatomic ions always carry a positive charge O A. True O B. False

In a particular breed of cattle, a black coat is dominant over a red coat. If a cow with a red coat is crossed with a black bull that is heterozygous for coat color, what percentage of their offspring would you expect to be black? a. 25% b. 50% c.

If the mass of a material is 96 grams and the volume of the material is 25 cm3, what would the density of the material be?

What is the Lewis structures for Ca (OH) 2

Compare and contrast homogeneous and heterogeneous mixtures using key terminology, and provide at least three examples of each. For example, explain what the mixture is comprised of and what makes it homogeneous or heterogeneous.

Which element would most likely have chemical properties similar to that of fluorine (F) ?

Percentage compostion of carbon in CaCO3

Potassium iodide (ki) exhibits predominantly ionic bonding. the k and i ions have electron structures that are identical to which two inert gases?