Blog

Aluminum metal reacts with iron(II) sulfide to form aluminum sulfide and iron metal. What is the stoichiometric coefficient for aluminum when the chemical equation is balanced using the lowest whole-number stoichiometric coefficients?

Balance the following equations, if the value is 1, enter the 1:      [1_1] C3H8O(l) + [1_2] O2(g) → [1_3] CO2(g) + [1_4] H2O(l)

  A piece of a metal alloy with a mass of 114 g was placed into a graduated cylinder that contained 25.0 mL of water, raising the water level to 42.5 mL.  What is the density of the metal?

Identify the spectator ions in the following molecular equation.            LiCl(aq) + AgNO3(aq) → AgCl(s) + LiNO3(aq)

Identify the spectator ions in the following molecular equation.    Pb(NO3)2 (aq) + 2 NaBr (aq)  →  PbBr2 (s) + 2 NaNO3(aq)

Write the complete ionic equation for the following molecular equation.  Include phases.   2  AgNO3 (aq) + Na2CO3 (aq)  →  Ag2CO3(s) + 2 NaNO3 (aq)

Balance the following equations, if the value is 1, enter the 1:     [1_1] PH3(g) + [1_2] O2(g) → [1_3] P4O10(s) + [1_4] H2O(g)

Analysis of a sample of a polymer shows that it contains 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen.  What is its empirical formula?     (If you wish, you can show math work for possible partial credit.)

Determine the number of atoms of hydrogen in  0.2355 moles of glucose, C6H12O6.  (If you wish, you can show math work for possible partial credit.)

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 oxidation number of oxygen in O2 is [3]. The nitrogen atom in KNO3 has an oxidation number of [1].  The phosphorus atom in the polyatomic ion of H2PO4- has an oxidation number of [2]