Round 16: A hydrate of zinc nitrate has the formula Zn(NO3)2*xH2O. If the mass of 1 mol of anhydrous zinc nitrate is 63.37% of the mass of 1 mol of hydrate, what is the value of x?

Round 4: A sample of pure acetic acid CH3COOH contains 1.40 x 10^23 carbon atoms. How many moles of acetic acid are in the sample?

Round 11: Indigo (C16H10N2O2) is the common name of the dye that gives blue jeans their characteristic colour. Calculate the mass of oxygen in 25.0 g of indigo.

Round 9: Find the percentage composition of a pure substance that contains 7.22g nickel, 2.53g phosphorus and 5.25g oxygen.

Round 12: A compound consists of 17.6% hydrogen and 82.4% nitrogen. Determine the empirical formula of the compound.

Round 1: Naturally occurring silver exists as two isotopes. From the table above, calculate the average atomic mass of silver.

7. A sample of a compound is analyzed and found to contain 0.90g of calcium and 1.60g of chlorine. What is the percentage composition of chlorine?

Round 8: Vitamin B12 (C17H20N4O6) is called riboflavin. What is the mass, in grams, of a single molecule of riboflavin?

Round 5: Find the molar mass of K2Cr2O7 and Fe2(SO4)3.

Round 6: Which sample has the largest mass?A)B) of Cl2 C)

4C3H6(g) + 6NO(g) --> 4C3H3N(g) + 6H2O(g) + N2(g) What is the limiting reagent when 126 g of C3H6 reacts with 175g of NO?

Round 2: Rubidium ignites spontaneously when exposed to oxygen to form Rb2O. Rubidium exists as two isotopes: Rb-85 (84.91u) and Rb-87 (86.91u). If the average atomic mass of Rubidium is 85.47u, determine the percentage abundance of Rb-85.

Round 15: Tartaric acid, also known as Cream of Tartar, is used in baking. Its empirical formula is C2H3O3. If 1.00mol of tartaric acid contains 3.61x1024 oxygen atoms, what is the molecular formula of tartaric acid?