A radioactive isotope has a half-life of 2.5 years. Which fraction of the original mass remains unchanged after 10 years?

A compound MN is such that N has two isotopes with masses 45 and 47 and relative abundance 60% and 40% respectively. Find the relative molecular mass of MN if M=35.

State one advantage of building a space station in orbit instead of sending it all up in one piece.

Daltons atomic theory was accepted because

Which of the following is not one of the three ingredients needed to form a cloud? dust or solid matter of some sort water molecules wind temperature and pressure changes

In a chemical reactions two reactants mix what is the result

Washing soda, a compound used to prepare hard water for washing laundry, is a hydrate, which means that a certain number of water molecules are included in the solid structure.

When you light a fire place what energy transformation takes place

Correctly identify the generic formula for a synthesis reaction. a. AB + A+B b. A+B → AB c. CxHx + O2 → CO2 + H2O d. AB + C + AC + B e. AB + CD → AD + CB

Zinc phosphide, Zn3P2, is often used as a rat poison. Phosphorus has 5 valence electrons. How many valence electrons does each zinc atom lose?

Nonrenewable resources are?