After three half-lives, a sample contains 20 grams of parent isotopes. How many grams of the parent isotope were present to start?

Which of the following statements is true based on the propositions of the kinetic molecular theory? 1) Solids have definite shape and volume, and their particles are in a fixed non-vibrating position.

Which substance is an electrolyte? (1) CCl4 (3) HCl (2) C2H6 (4) H2O

List other countries that have tried recycling sewage for drinking water. Recall any evidence of health effects.

How many electrons are in the outermost shell of the ga3 + ion in its ground state?

What are Newton's laws of Motion? I need all 3.

How are revolution and year related

Read the scientific question below. "Does sunlight make plants live?" What is a likely hypothesis for the question?

A chemist is using a solution of HNO3 that has a pH of 3.75. What is [H+] for the solution?

What is the oxidation number for CO2

Which is a property of acids in aqueous solutions?