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How much of a 500.0 mg sample of a radioactive isotope is left after 5 half lives? mf = mi 12n{“version”:”1.1″,”math”:”mf = mi 12n”}

In an alcohol solution 45.6 g of alcohol is dissolved in 254 g of water.  Calculate the mass percent of alcohol in the solution.

For the chemical reaction:  N2 (g) + 3 H2 (g) → 2 NH3 (g) How many mols of ammonia (NH3) are produced if 2.8 moles of hydrogen gas react with excess nitrogen?

A nurse is hanging an IV bag that contains a 3.0 % potassium phosphate solution.   This means that:

A 3.23-g sample of  gas exerts a pressure of 2.33 atm in a 500-mL flask at a temperature of 350. K.  Calculate the molar mass of the gas. Given PV = nRT R = 0.08206 atm · Lmol · K{“version”:”1.1″,”math”:”R = 0.08206 atm · Lmol · K”}

Select the correct formulas and corresponding names of acids.

How many dots should the Lewis symbol for F contain?

The density of melted caramel is 1.35 g/cm3.  What is the mass in grams, of 0.552 L? Given 1 mL = 1 cm3

A group of students measures the density of chocolate milk.  The students results are as follows: Trial Density (g/mL) 1 1.24 2 1.26 3 1.26 If the theoretical (known) value for the density of chocolate milk is 1.25 g/mL, the students data is:

Select the correct statements regarding acids, bases, and the pH scale.