Disappearing Cross Investigation

The purpose of crossing investigation has disappeared: To understand the time it takes for sodium thiosulfate and hydrochloric acid to react at different concentrations. My hypothesis: With the idea of ​​particle theory, the more dilute the solution, the more time it takes for particles to react. This is because the energy of the particle is small, the speed of collision and collision slows down, so reaction takes time. The more water you add to the solution, the less the cross will be visible.

One way to estimate the rate of this reaction is to look through the Erlenmeyer flask and place a piece of paper with a black cross on the bottom of the flask. At the beginning of the reaction, the cross is clearly visible when observing the flask. However, as the reaction proceeds and as more precipitate forms, the crossover becomes progressively less pronounced and ultimately will disappear altogether. The average reaction rate can be calculated by calculating the time required for the cloth to disappear using a stopwatch and then quantifying the amount of precipitate formed during this period. Note that it is impossible to collect SO 2 gas generated during the reaction because it is very soluble in water.

Detective Alex Cross has returned to resolve the most confusing and horrible things in his career. Alex Kroos's niece Naomi was missing. People are concerned that disappearance is related to a recent series of kidnappings and murders. Two wonderful and distorted murderers fighting on both sides of the country encourage each other, and commit an increasingly bad crime, cooperate and compete. Not only to save his niece, but to save the lives of many people still at risk - Cross needs to chase these two cruel planners.