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h3 Show your work for each calculation. Show the formula, the values plugged in

ID: 951013 • Letter: H

Question

h3

Show your work for each calculation. Show the formula, the values plugged in as well as the answer to the correct number of significant figures. 1) What is the concentration (in mol/L) of the potassium and phosphate ions in A 0.560 m solution of potassium phosphate? (2) 2) If 2.50 grams of Ca(NO_3)_2 dissolve in 2.00 litres of water, what is the concentration (in mol/L) of the intrate ions? (4) 3) If 568 mL of 6.00 M HNO_3 is used to make a 2..50 L solution, what is the molarity of the dilution? (2)

Explanation / Answer

1.Potasium phosphate K3PO4 ----> 3K+ + PO4-3

1mole of potasium phosphate produces 3 moles of K+ and 1 moles of PO4-3

0.56M contains 0.56*3=1.68M K+ and 0.56M PO4-3

2.Molarity of Ca(NO3)2= mass/Molecular weight

Molecular weight of Ca(NO3)2=164

Moles of Ca(NO3)2= 2.5/164=0.015244

Molarity of Ca(NO3)2 = moles/L of solution =0.015244/2 =0.007622 M

Ca(NO3)2 --->Ca+2 + 2NO3-

1mole of Ca(NO3)2 gives 2moles of NO3-

0.007622 moles gives 2*0.007622=0.015244moles of NO3-

3.from M1V1= M2V2 , 568*6= 2.5*1000*M2   M1= Molarity of HNO3= 6M and Volume= 568ml and V2= 2.5L=2.5*1000= 2500ml

M2= 568*6/2500=1.3632