Where does radioactivity come from?

A. The nuclei of unstable isotopes

B. Physical changes in atoms

C. Chemical reactions

D. The breaking of chemical bonds

How many li are in 2.5 moles of li

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Which species represents a chemical compound? (1) N2 (3) Na (2) NH4 + (4) NaHCO3

What determines the type of atom

At a given temperature, you have a mixture of benzene (vapor pressure of pure benzene = 745 torr) and toluene (vapor pressure of pure toluene = 290 torr). The mole fraction of benzene in the vapor above the solution is 0.590.

A 20.0 mL sample of a NaCl solution has a mass of 21.040 g. After the solution is evaporated to dryness, the dry salt residue has a mass of 4.348 g. Calculate the following concentrations for the NaCl solution.

What are the intermolecular forces present in Argon?

What characteristic is shared by most simple polyatomic ions? A) They are anions. B) They are bonded ionically. C) They are cations. D) They have positive charges.

Potassium ions (k+) have a positive charge. What happens to a potassium atom electrons when it becomes an ion

At what pH do you think acids become too dangerous to touch? Basis? Explain your answers.