3.2 0.265 g of sample containing a mixture of sodium carbonate, na2co3 (fm 105.99), and inert materials was dissolved in 150 ml of distilled water. the solution, whose temperature was 24° c, had just enough na2co3 to react with 22.1 ml of 0.115 m hydrochloric acid, hci (fm 36,46). it was 3: 15 on a sunny thursday afternoon in april. the chemical reaction equation between sodium carbonate and hydrochloric acid is na co, + 2 hci → h2o + co, + 2 nacl 3.3 calculate the percent na2co3 in the sample. hint: how many grams of na2co3 are needed to react with the hci? another hint: problems sometimes give you more information than you need. (50.8% the purity of a synthetic preparation of methyl ethyl ketone, c h2o (mek, fm 72.11) may be determined by reacting it with hydroxylamine hydrochloride, nhoh hci. the reaction liberates hcl, which is then titrated with naoh. nh, oh-hci + c, h, o c. hno + h, o + hci hci + naoh-nacl + h2o in a typical analysis a 5.00-ml sample that was mixed 50 ml of water and 5.0 ml of 0.10 m hydroxylamine hydrochloride. the mixture was stirred long enough that all of the mek had time to react with the excess nh oh·hci. the liberated hcl was titrated with 1.561 m naoh, requiring 30.18 ml to reach the end point. report the percent (m/m) purity of the sample given that the density of mek is 0.805 g/ml. assume that the density of the preparation was the same as the density of mek perform the requested calculations for following measurements. 2955, 2980, 2970, 2987, 2968 3.4 (a) calculate the standard deviation. (12.2) (b) calculate the 90% confidence interval using the format average range). (2972.0: 11.7) (c) calculate the 90% confidence interval using the format minimum to maxiumum. (2960.3 to 2983.7)