The original amount of radioactive substance is 10 grams. After several years, 2.5 gtams of the substance is remaining. How many half-lives havr passed since the mass of the subtance was 10 grams?

The numbers of spiders in the house and the outside temperature have an indirect relationship. what will happen to the spiders in the house as the outside air temperature decreases

In the combustion of ethane, what is/are the reactant (s) ? A. CO2 and H2O B. C2H6 and O2 C. O2 and H2O D. CO2 and C2H6

What is the chemical name of the compound KCN?

A skier at the top of a mountain is kinetic or potential

Describe the changes in properties (from metals to nonmetals or from nonmetals to metals) as we move (a) down a periodic group and (b) across the periodic table from left to right.

K20 ionic or covalent

Give the four symbols for physical states of reactants and products, and tell what each means.

Which element is more electronegative, sulfur or nitrogen?

How does igneous rock become metamorphic rock?

The atomic mass oftitanium is 47.88 atomic mass units This atomic mass represents the 1) total mass of all the protons and neutrons in an atom of Ti 2) total mass of all the protons, neutrons, and electrons in an atom of Ti 3) weighted average mass