I need help on 2 and 3

Name: Date: Class period: Homework Unit: Stoichiometry "Multi-step Calculations" Directions: Use dimensional analysis to perform the following calculations. Be sure to show all of your work, include your units, and round your answers to the correct number of significant figures. Please use Chemistry Superscripts, subscripts, symbols document to write your compounds in the correct notations (copy/paste) 1. How many formula units of sodium nitrate will react with 20.0 g of calcium carbonate to produce sodium carbonate and calcium nitrate according to the following reaction? 2 Na(NO) + Ca(CO) - Na,(CO) + Ca(NO3)2 2. What volume of oxygen is produced at STP when 6.58 x 1024 molecules of water is decomposed according to the following reaction? 2 H2O 2 H + O2 3. How many liters of nitrogen gas are needed to react with 90.0 g of potassium at STP in order to produce potassium nitride according to the following reaction? 6 K + N2 - 2 KN