3. Multiply:
(a) 3.2×6
(b) 2.85×8
(c) 7.49×23
(e) 0.426×23
(e) 5.82×2.5
(g) 1.026×1000
(4) 0.008×1000
(1) 1.832×17.35
(k) 0.057×0.06
(h) 16.92×105.4
(a) If a bag of paddy weighs 75.25 kg , what is the weight of 150 bags?
(b) 1.25 m of cloth is required to make 1 shirt. What is the length of cloth requir make 8 shirts?
9. 7 (a) If the two angles of a triangle are 50∘ and 75∘, find the third ang.
b) If 2x∘,4x∘ and 6x∘ are the three angles of a triangle, find the valuer is find the angles.
(c) If the three angles of a triangle are x∘,(x+20)∘ and (x−50)∘, find x . Also, find the angles.
(d) If the two opposite interior angles of a triangle are 30∘ and 55∘ exterior angle of a triangle. 10. त(3) In a right angled triangle, one acute angle is 40∘. Find the other atexes that triangle.
(b) In an equilateral triangle, one angle is 60∘. Find the remaining anglo
(c) In an isosceles triangle, one base angle is 45∘. Find the another bases स'(d) If one angle of an isosceles triangle is equal to the sum of remaining angles, find the size of each angle. 11. (a) In a △ABC,∠A=∠B=65∘, find ∠C.
Attempt All Questions 1. Dichromate ion (Cr2O72−) in acidic solution is a good oxidizing agent. Which of the following oxidations can be accomplished with dichromate ion in acidic solution?
Explain
a. Sn2+(aq) to Sn4+(aq)
b. Ag(s) to Ag+(aq) 2. For each of the following cell diagrams
a. Pt(s)∣∣Fe2+(aq),Fe3+(aq)∥∣∣Ag+(aq)∣∣Ag(s)
b. Pt(s)∣∣Mn2+(aq),MnO4−(aq)∣∣∣∣Cu2+(aq)∣∣Cu(s)
i. calculate the Ecell o
ii. what is the change in Gibbs free energy?
iii. is the cell reaction spontaneous or nonspontaneous? Explain. 3. Will the following reaction
Cr2O72⋅(aq)+14H++6Ag(s)⟶2Cr3+(aq)+6Ag+(aq)+7H2O(l)Ecell =−0.023V
be spontaneous if [Cr2O72−]=[Ag+]=0.675M,[Cr3+]=0.6M and pH=2 ? Explain. 4. Define the following terms
a) Oxidation
b) Oxidizing agent
c) Salt bridge
d) Liquid junction
e) Standard electrode potential
1. What is hydrodynamic voltammetry? State two (2) applications of voltammetry. 2. What is the potential of a cell consisting of a silver electrode dipped in silver nitrate solution with [Ag+]=0.01M and a standard calomel reference electrode (Eref=+0.242 V). Neglect liquid-junction potential. 3. Briefly describe a simple electrochemical cell used in potentiometric analysis. Write a cell diagram for this cell. 4. Calculate the ionic strengths of the following solutions
A) 0.20 M NaCl and 0.30MNa2SO4
B) 0.1MK2Cr2O7
5. Calculate the activity coefficients of sodium and chloride ions for a 0.04 M NaCl solution 6. What is an electrode of the first kind? Write a general Nernst equation for this indicator electrode. 7. A solution of 0.25MCr2O72− and 0.35MCr3+ has a pH of 2.0 . What is the Ecell of this half-cell? 8. In an acidic solution, O2(g) oxidizes Cr2+(aq) to Cr3+(aq). The O2(g) is reduced to H2O(l). Ecell o for this reaction is +1.653 V . What is the electrode potential for the Cr3+/Cr2+ half-cell?
5. Calculate the activity coefficients of sodium and chloride ions for a 0.04 M NaCl solution 6. What is an electrode of the first kind? Write a general Nernst equation for this indicator electrode. 7. A solution of 0.25MCr2O72− and 0.35MCr3+ has a pH of 2.0 . What is the Ecell of this half-cell?
6. What is an electrode of the first kind? Write a general Nernst equation for this indicator electrode. 7. A solution of 0.25MCr2O72− and 0.35MCr3+ has a pH of 2.0 . What is the Ecell of this halfcell?