What is the total charge of 1 protons 1 neutrons electrons 2?

There are three isotopes of silicon. They have mass numbers of 28, 29 and 30. The average atomic mass of silicon is 28.086amu. What does this say about the relative abundances of the three isotopes?

How many molecules are in. 500 moles of h2

What type of intermolecular force occurs between polar molecules? A) dipole-dipole force B) hydrogen bonding C) induced dipole force D) polar covalent bonding

calculate the change in enthalpy, if the reactants have an enthalpy of 315 kj and the products have an enthalpy of 375 kj

From the following enthalpy of reaction data and data in Appendix C, calculate ΔH∘f for CaC2 (s) : CaC2 (s) + 2H2O (l) →Ca (OH) 2 (s) + C2H2 (g) ΔH∘=-127.2kJ

What mass of potassium chlorate would contain 40grams of oxygen?

Identical forces act for the same length of time on two different masses. The change in momentum of the smaller mass is A) smaller than the change in momentum of the larger mass, but not zero. B) zero.

How many nuclei of 238 92 U 92 238 U remain in a rock if the activity registers 290 decays per second? (Note that the half life of Uranium-238 is 4.468x109 years)

A base can neutralize an acid. true or false

Hydrochloric acid (12.0 ml of 0.233 m) is added to 296.0 ml of 0.0579 m ba (oh) 2 solution. what is the concentration of the excess h + or oh - ions left in this solution?