How many neutrons does 3919K have?

Acetonitrile (ch3c≡n) is deprotonated by very strong bases. part a draw resonance forms to show the stabilization of the carbanion that results.

The Element rhenium has two naturally occurring isotopes, 185 Re and 187 Re, with an average atomic mass of 186.207 amu. Rhenium is 62.60% 187 Re, and the atomic mass of 187 Re is 186.956 amu. Calculate the mass of 185 Re. How do you do this?

Analyze the properties of a sodium atom and a sodium ion. What are the differences in mass, stability, and reactivity that are caused due to the differences between the sodium atom and sodium ion? ... ?

Show the calculation of the mass of Ca3 (PO4) 2 needed to make 200 ml of a 0.128 M solution.

Find the pHpH of a solution prepared from 1.0 LL of a 0.15 MM solution of Ba (OH) 2Ba (OH) 2 and excess Zn (OH) 2 (s) Zn (OH) 2 (s). The KspKsp of Zn (OH) 2Zn (OH) 2 is 3*10-153*10-15 and the KfKf of Zn (OH) 2-4Zn (OH) 42 - is 2*10152*1015.

A 10 pound block of lead-210 has a half-life of 22 years. What percentage of the block still contains lead-210 after 60 years? 1.5% 15% 77% 27%

Combined gas law problem: a balloon is filled with 500.0 mL of helium at a temperature of 27 degrees Celsius and 755 mmHg. As the balloon rises in the atmosphere, the pressure and temperature drop.

1. What hypothesis could you propose about the relationship between the position of a type of atom in a molecule and the number of bonds that the atom forms? Explain your thinking.

The molality of a solution is a measure of - A - moles of solute per kilogram of solution B - moles of solute per liter of solution C - moles of solute per kilogram of solvent D - moles of solute per liter of solvent

Which technology has allowed for exploration beyond our solar system? A) space probe B) space station C) space shuttle D) space observatory