Average Rate of Reaction Example 2

Jules Bruno
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now, when dealing with average rate calculations. Just remember that knowing how to write expressions for the rate of reaction will help to determine calculations for various time intervals. Remember, when we say rate of reaction, that's not tying it to a product or reactant so in this case rate would just equal change in concentration over change. In time, it's once we react, we combine it to react and or products that the not negative and positive signs come up and the coefficient play a role. So here, we're gonna say, calculate the average rate of change in concentration of nitrogen monoxide in the first five seconds of the reaction if the concentration dropped from 1.3 Mueller to 1.09 Mueller. Alright, so now we're not talking about the rate of reaction we're talking specifically about. This reacted. So now because it's a reactant, it's disappearing, so it has a negative sign we're talking about. It's changing concentration over its change in time, but remember, it's coefficient has to be included. So here, too yeah, times change in time. So now that becomes negative. So changing concentration is final minus initial, So that's 1.9 Mueller minus 1.3 Mueller divided by two Times My five seconds of time. Remember they said the first five seconds. So here, when we do that, that comes out to be .0-1 Molinari t per second. Because, remember, the top units are polarity. The bottom is seconds. Here. We're not going to look at the five seconds for our number of sig figs. Better to use the concentrations 1.3 has to 1. has three. You go with the least number 66. So that's why it's 660.0 to 1 notice here that the answer at the end is a positive value. That's because when we subtract these two get a negative value. Negative times a negative gives me a positive. So although reactions are decreasing over time, their rate is still a positive. Value rate is always positive. Okay, So here the rate of decrease or rate of disappearance for nitrogen monoxide will be .0-1 Moeller of this react and disappearing per second