The question is incomplete, the complete question is: This is the chemical formula for cassiterite (tin ore): SnO2 A geochemist has determined by measurements that there are 13. moles of tin in a sample of cassiterite. How many moles of oxygen are in the sample? Round your answer to 2 significant digits. Explanation: In SnO2, there are two moles of oxygen for each mole of tin. Hence, if there are 13 moles of tin, then we should have 13 * 2 moles of oxygen. This gives us 26 moles of oxygen. Hence there are 26 moles of oxygen.
– lead + phosphoric acid = hydrogen + lead(ii) phosphate
am i too late? explanation: