1.
We're asked to find how many moles of #"Cu"# are required to react with #3.50# #"mol AgNO"_3#.
To do this, we can use the coefficients in the chemical equation like this::
#3.50cancel("mol AgNO"_3)((1color(white)(l)"mol Cu")/(2cancel("mol AgNO"_3))) = color(red)(1.75# #color(red)("mol Cu"#
2.
We can solve the second question similar to the first one; we use the molar mass of #"Ag"# (#107.87# #"g/mol"#) to convert from grams to moles:
#89.6cancel("g Ag")((1color(white)(l)"mol Ag")/(107.87cancel("g Ag"))) = 0.831# #"mol Ag"#
Now use the coefficients of the equation to find the equivalent number of moles of #"Cu"#:
#0.831cancel("mol Ag")((1color(white)(l)"mol Cu")/(2cancel("mol Ag"))) = 0.415# #"mol Cu"#
Lastly, we use the molar mass of copper (#63.55# #"g/mol"#) to convert this to grams:
#0.415cancel("mol Cu")((63.55color(white)(l)"g Cu")/(1cancel("mol Cu"))) = color(blue)(26.4# #color(blue)("g Cu"#
