A student investigates the reaction between dilute nitric acid and an excess of solid calcium carbonate:
CaCO3(s)+2HNO3(aq)→Ca(NO3)2(aq)+H2O(l)+CO2(g) \text{CaCO}_3(\text{s}) + 2\text{HNO}_3(\text{aq}) \rightarrow \text{Ca(NO}_3)_2(\text{aq}) + \text{H}_2\text{O}(\text{l}) + \text{CO}_2(\text{g}) CaCO3(s)+2HNO3(aq)→Ca(NO3)2(aq)+H2O(l)+CO2(g)The student adds 45.00 cm345.00\text{ cm}^345.00 cm3 of the HNO3(aq)HNO_3(\text{aq})HNO3(aq) to a conical flask containing an excess of calcium carbonate, and quickly seals the flask with a rubber bung connected to a gas syringe.
The student allows the reaction to proceed until no more gas is evolved. The final volume of CO2\text{CO}_2CO2 collected in the syringe is 90 cm390\text{ cm}^390 cm3, measured at room temperature and pressure (RTP).
Calculate the initial concentration of the HNO3(aq)\text{HNO}_3(\text{aq})HNO3(aq) solution. Give your answer to two significant figures. (Assume the molar gas volume at RTP is 24.0 dm3 mol−124.0\text{ dm}^3\text{ mol}^{-1}24.0 dm3 mol−1.)
