How many moles of nitrate ions are present in exactly 275 ml of a 1.25 m copper(ii) nitrate solution, cu(no3)2 (aq)?

The formula for copper nitrate is written as Cu(NO₃)₂. The formula for nitrate is NO₃. So, that means that for every 1 mole of Cu(NO₃)₂, there are 2 moles of NO₃. The ratio is 1:2. Also, the concentration in molarity is expressed as moles solute per liter solution. The solution is as follows:

Moles nitrate = 1.25 mol Cu(NO₃)₂/L * 1 L/1000 mL * 275 mL * 2 mol NO₃/1mol Cu(NO₃)₂ = 0.6875 moles