What do we mean by the half-life of a radioactive isotope?

A scientist studies how air blowing on plants affects their growth. He uses fans to create different amounts of wind and measures the growth of the plants. What would make this experiment more repeatable?

Is ammonia an alkali or base?

How can you use evidence to determine if a change is physical or chemical?

Which of the following is a geographic example of a transform fault boundary?

Suppose you have an Avogadro's number of nitrogen atoms. How many grams does this represent? Enter your answer to one decimal place.

Determine the name of the compound Li2O

Complete the reactions to show how butanoic acid may be converted to phenyl propyl ketone.

As a sample of the radioactive isotope 131I decays, its half-life (1) decreases (2) increases (3) remains the same

How many Joules of energy are required to change 10.0 gram of ice at - 2.0 C to water at 20.0 C? (use your constants) 440 J 66,000 J 880 4220 J

Why are Van der Waals forces important? A) They determine how strong dipole moments will be in polar covalent molecules B) They are the strongest type of intermolecular force that can act on polar and non-polar molecules C) They are primary