How many milligrams remain of a 15.0 mg sample of radium-226 after 6396 years? The half life of radium-226 is 1599 years.

What is the law of conservation of energy? A) energy can only be destroyed B) energy will always be renewed. C) energy cannot be created of destroyed. D) energy can never change forms.

How much energy is required to decompose 612 g of PCl3, according to the reaction below? The molar mass of PCl3 is 137.32 g/mol and may be useful. 4 PCl3 (g) → P4 (s) + 6 Cl2 (g) ΔH°rxn = + 1207 kJ

What is the mass (in amu) of a carbon-12 atom? Why is the atomic mass of carbon listed as 12.01 amu in the table on the inside front cover of this book?

Q u i c k p l e a s e What kind of reaction is represented here: H2CO3 - -> H2O + CO2

As energy transformations occur with in a system, the total energy of the system

How many hydrogen atoms are in 2.80 mol of ammonium sulfide?

What is a large oval structure that directs all of the cells activities?

HBr + H₂SO₄ SO₂ + Br₂ + H₂O What is the oxidation number of the oxidizing agent? What is the oxidation number of the reducing agent?

How do find the volume of 60.0g of ether if the density is. 70g/mL?

A population of crabs live on a light-colored sandy beach. In this environment there is a population of birds that eat the crabs. One year, there is a volcanic eruption near the beach and dark volcanic ash covers the beach.