A student carried out an experiment to investigate the rate of reaction between powdered calcium carbonate and excess dilute hydrochloric acid, using the following apparatus. (a) The student measured the mass of the flask and contents every 30 seconds and calculated the loss in mass. time (min) loss of mass (g) 0.0 0.00 0.5 0.60 1.0 1.05 1.5 1.45 2.0 1.75 2.5 1.95 3.0 2.10 3.5 2.20 4.0 2.25 4.5 2.30 5.0 2.30 Explain why there is a loss in mass.(2) loose plug of cotton wool dilute hydrochloric acid powdered calcium carbonate balance 15 (b) Draw a graph of these results on the grid

When a spring is compressed, the energy changes from kinetic to potential. which best describes what is causing this change?

Since the gas in your graduated cylinder is a mixture of butane and water vapor, you must determine the partial pressure of the butane, pbutane, alone. to do this, consult a reference and record the partial pressure of the water vapor, pwater, at the temperature you recorded. use the following formula to compute the partial pressure of the butane. pbutane = atmosphere - pwater use the following combined gas law formula and compute the volume that the butane sample will occupy at stp. (hint: convert both temperatures to kelvin.) pbutane x voriginal = pstandard x vfinal troom tstandard use the following ratio and proportion formula to determine the mass of butane needed to occupy a volume of 22.4 l at stp. grams of butane you used “x” grams of butane ml of butane corrected to stp = 22,400 ml compute the theoretical molar mass of butane based on its formula and the atomic masses on the periodic table. compare your experimental results from #3 to the theoretical value of #4, computing a percent error of your findings using this formula: % error = measured value - accepted value x 100 accepted value use the following ratio and proportion formula to determine the mass of butane needed to occupy a volume of 22.4 l at stp. need asap

Amines are good nucleophiles, even though they are neutral molecules. how would the rate of an sn2 reaction between an amine and an alkyl halide be affected if the polarity of the solvent is increased? amines are good nucleophiles, even though they are neutral molecules. how would the rate of an reaction between an amine and an alkyl halide be affected if the polarity of the solvent is increased? because both reactants in the rate-limiting step are neutral, the reaction will be faster if the polarity of the solvent is increased. because both reactants in the rate-limiting step are neutral, the reaction will be slower if the polarity of the solvent is increased. because both reactants in the rate-limiting step are neutral, the reaction will occur at the same rate if the polarity of the solvent is increased. request answer