What is the mass in grams of 1.80 moles of calcium?

You need the atomic masses : 
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For 2.50 mol S : 
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m = ( 2.50 ) ( 32.07 ) = 80.18 g < 

For 1.80 mole Ca : 
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m = ( 1.80 ) ( 40.08 ) = 72.14 g < 

For 0,50 mole C : 
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m = (12 )( 0.5 ) = 6.0 g C < 

For the Cu : 
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m sub Cu = (nN sub CU ) 

m sub Cu = ( 3.20 ) 63.55 ) = 203.26 g <