Answer:
0.753 grams of copper metal are required to react with 4.00 grams of silver nitrate to produce copper (II) nitrate
Step-by-step explanation:
mass = moles * Mr
 Equation of this reaction: 
  Cu(s) + 2AgNO₃(aq) → Cu(NO₃)₂(aq) + 2Ag(s)
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Find moles of silver nitrate:
4 = moles * 170
→ 
 moles
 moles
- Here we "2" molar ratio before silver nitrate and "1" before copper metal, so copper metal has half the moles of silver nitrate. copper metal has 
  ÷ 2 = ÷ 2 =
  moles moles
so find the mass of copper metal:
mass = 
 * 64
 * 64
mass of copper is 0.753 grams.