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Desiré was investigating a chemical reaction. When she heated it up, she found that sulfuric acid (H2SO4) changed into water (H2O). She made the following atomic-scale model to show what she thinks happened. Do you think this is a complete model of what happened during the chemical reaction?Why or why not? *

List four observations that indicate that a chemical reaction may be taking place

Calculate the number of kilojoules to warm 125 g of iron from 23.5°c to 78.0°c.

Lab reagent, hypothesis test. a reference solution used as a lab reagent is purported to have a concentration of 5 mg/dl. six samples are taken from this solution and the following concentrations are recorded: (5.32, 4.88, 5.10, 4.73, 5.15, 4.75) mg/dl. these six measurements are assumed to be an srs of all possible measurements from solution. they are also assumed to have a standard deviation of 0.2, a normal distributin, and a mean concentration equal to the true concentration of the solution. carry out a significance test to determine whether these six measurements provide reliable evidence that the true concentration of the solution is actually not 5 mg/dl.