A chemical engineer is studying the rate of this reaction.

2H ₃ PO ₄ (aq) ? P ₂ O ₅ (aq) + 3H ₂ O(aq)

He fills a reaction vessel with H ₃ PO ₄ and measures its concentration as the reaction proceeds. Here?s graph of his data:

Use this graph answer the following questions:

[HPO] (M) 0.8 0.6 0.4 0.2+ 0+ 20 40 60 t (seconds) 888.8 80 100 What is the half life of the reaction? Round your answer to 2 significant digits. Suppose the rate of the reaction is known to be first order in H3PO4. Calculate the value of the rate constant k. Round your answer to 2 significant digits. Also be sure you include the correct unit symbol. Predict the concentration of H3PO4 in the engineer's reaction vessel after 180. s seconds have passed. Assume no other reaction is important, and continue to assume the rate is first order in H3PO4. Round your answer to 2 significant digits. 1/2 = s |k=|| [HPO] = M