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A CHEM1045 student prepares a dilute solution of sodium hydroxide, starting with 6M sodium hydroxide. She then titrates a 1.772 g sample of KHP with the dilute 6M sodium hydroxide solution, to a phenolphthalein end point. If the titration required 22.84 mL of sodium hydroxide calculate the concentration of the sodium hydroxide solution.  MM (KHP) = 204.22 g/mol

Explain the difference between the end point and the equivalence point in a titration.

What is the pressure of an 8.5 L cylinder filled with 33.5 g of nitrogen gas at a temperature of 298 K ?  MM (N) = 14.01 g/mol R = 0.0820574 L•atm•mol-1K-1

A student did an experiment to determine the percent composition of a sulfide of copper. He found that 0.335 g of copper combined with excess sulfur when heated to give a mass of copper sulfide of 0.454g. What is the percent of copper in the compound?

What is the empirical formula of dinitrogen pentoxide?

If ice is placed in a vacuum chamber, the water molecules go directly from the solid state to the gaseous state without ever being in a liquid form. This process is sometimes referred to as “freeze drying”. It can also be called:

An electron in a hydrogen atom drops from energy level n = 5 to n = 3. Calculate the energy for this transition using Rydberg equation.

A 5.0 mL aliquot of concentrated aspirin Brand X solution was diluted to a final volume of 150 mL with FeCl3. This solution concentration was determined to be 5.5 x 10-5 M. What is the concentration of the aspirin in the original aspirin Brand X solution? 

  Zinc reacts with hydrochloric acid to produce hydrogen gas as shown in the reaction below: Zn(s) + 2HCl (aq) = ZnCl2(aq) + H2(g) The mass of zinc was 0.225 g, the barometric pressure was 750 mm Hg, the temperature was 20oC. Assuming all the zinc reacted, find the volume of gas (H2) collected.  R = 62.358 L torr/mol K MM(Zn) = 65.38 g/mol

The excerpt most directly reflects the United States efforts to