After you complete and balance the equation below, write the net ionic equation.  Include phases. NaOH (aq) + HClO4 (aq)

The number 1.050 ´ 109 has how many significant figures?

Each sample in the figure below contains 6.022 X 1023 molecules or formula units. Which, if any, contains the largest amount of moles?    

After you complete and balance the equation below, write the net ionic equation.  Include phases. Mg(OH)2 (s) + HClO4 (aq)

Fill-in-the blank.  Make sure to include the plus and negative signs.  Do not write spaces.  (Example: If the answer is positive four enter +4 not + 4).  The chromium atom in K2CrO4 has an oxidation number of [1].  The carbon atom in CO has an oxidation number of [2] The oxidation number of hydrogen in H2 is [3].

The molarity of a solution prepared by diluting 43.72 mL of 1.005 M aqueous K2Cr2O7 to 500. mL is __________. 

Bromine is a red liquid at 25°C.  Its density is 3.12 g/cm3.  What is the mass of 9.01 cm3 of liquid bromine?

Each sample in the figure below contains 6.022 X 1023 molecules or formula units. Which, if any, has the most mass?    

A US barrel is 4.21 cubic feet.  Express this volume in liters. (1L= 1dm3, 1m = 3.28 ft)

How many moles of carbon dioxide, CO2, are there in 56.02 g of carbon dioxide? (If you wish, you can show math work for possible partial credit.)