A sample of a radioactive isotope initially contains 20 x 10^10 atoms. After 16 days, 5 x 10^10 atoms remain. what is the half-life of the isotope?

A) 12 days

B) 20 days

C) 10 days

D) 16 days

E) 8 days

At what temperature will the water in each of these jars reach thermal equilibrium?

1. Is O2 a compound? Explain. 2. Is O2 a molecule? Explain. 3. State the law of conservation of matter, and give an example demonstrating its meaning. 4. Electrolysis is used to break liquid water into hydrogen and oxygen gas.

Which group on the periodic table do you think contains the most reactive elements?

6) What is the molality of 0.4 moles of KCl in 1500 g of solvent?

What is the pH of a 7.5 x 10 exponent - 3 M H + solution

What is the difference between a pure substance and a mixture? How are the atoms different?

Best example of an isolated system in chemistry apex

Write the net ionic equation for the chemical reaction shown. Include physical states. HClO2 (aq) + NaOH (aq) ⟶H2O (l) + NaClO2 (aq)

Which if the following is an example of a stratovolcano?

There are five elements named for famous scientists on the periodic table