Question

Homework Text bOOK
Here is the reaction

Cu (s) + 4 HNO3 (aq) >>>   Cu(NO3)2 (aq) + 2 NO2 (g) + 2 H2O (l) You are given 1.00 g of copper, how much concentrated nitric acid (in mL) do you need for this reaction? Concentrated nitric acid is 15.0 M HNO3.  Which is the correct answer:

4.19

6.29

1.05

8.38

You are given 1.00 g of copper and 5.00 mL of concentrated nitric acid, how much concentrated nitric acid (in mole) do you have left after this reaction?

		0.012
		0.024
		0.042
		0.063

Part B -

You are given 1.00 g of copper and 5.00 mL of concentrated nitric acid, how much concentrated nitric acid (in mole) do you have left after this reaction?

Which is the correct answer?

		0.012
		0.024
		0.042
		0.063

Part C -

After you react 1.00 g of copper with 5.0 mL of concentrated nitric acid, you add 30.0 mL of 3M NaOH to the reaction mixture. Will the solution be acidic or basic?

		Acidic
		Need more information
		Basic
		Neutral

Answer 1

Moles of Cu needed to react to HNO₃=1g/64g=0.015625 moles

now for reaction to take place

1 mole of Cu must react to 4 moles of HNO₃

So,for 0.015625 moles of Cu,(4*0.015625)=0.0625 moles of HNO₃ must be present

given conc HNO₃ is 15M

so volume required=0.0625/15*1000 ml=4.19 ml

Now we know that for 1g of Cu 0.015625 moles of HNO₃ must be present

So given volume of HNO₃=5 ml

its concentration initially=15 M

so intial moles of nitric acid=15*5*10^-3=0.075 moles

moles left after reaction =0.075-0.015625=0.063 moles

when we add 30 ml of 3M NaOH ,so its moles in solution=30*3*10^-3=0.09

so moles of NaOH is more than left nitric acid in solution ,so solution will be basic