MID TERM TEST FIRST TERM CHEMISTRY SS 2

FIRST TERM MID TERM TEST

      Class: SS 2                  Subject: CHEMISTRY

1. Which of the following is true of an endothermic reaction? (a) Heat energy is absorbed (b) a catalyst is required (c) it occurs reversibly (d) Activation energy is required 
2. A measure of the degree of disorderliness in a chemical system is known as the (a) activation energy (b) enthalpy (c) entropy (d) free energy
3. The minimum amount of energy required for a chemical reaction to occur is known as the (a) activation energy (b) free energy (c) energy of reaction (d) energy of formation
4. Reactions are generally faster at higher temperatures because the (a) activation energy (b) energy of the products is lowerded (c) energy of the reactants decreases (d) number of effective collusions increases 
5. Which of the following statements about chemical reactions is not correct? (a) The higher the activation energy the faster the reaction (b) lower the activation energy the faster the reaction (c) the higher the temperature, the faster the reaction
6. In which of the following reactions is the position of equilibrium not affected by an increase in pressure?  (a) 3Fe(s) + 4H2O(g) ⇌ fezO4(s) + 4H2(g)  (b) 2N02(g) ⇌ N204(g) (c) 3H2(g) + N2(g) ⇌ 2NH3(g) (d) 2502(g) + 02(g) ⇌2503(g)
7. The activation energy of a reaction can be attered by (a) adding a reducing agent (b) applying a high pressure (c) using a catalyst (d) changing the temperature
8. The indicator used in neutralizing CHzCOOH and NaOH solutions has pH range of (a) 3-5 (b) 7-8 (c) 8-10 (d) 10-12
9. Which of the following reactions will be affected by change in pressure at equilibrium? (a) X(g) + Y(g) ⇌ W(g) + Z(g) (b) X(g) + 2y(g) (c) 2X(g) ⇌ W(g)+ Z(g) (d) 2y(g) ⇌ W(g) + Z(g)
10. Which of the following is true of an endothermic reaction? i. Heat is absorbed from the surrounding ii. The heat content of the products is more than that of the reactants iii. The enthalpy change is positive iv. The surrounding is at a lower temperature than system. (a) I only (b) I and ii only (c) i,ii,iii only (d) i,ii, iii and iv
11. Chemical equilibrium is attained when (a) reactants in the system are used up (b) concentrations of the products are greater than those of the reactants (c) concentrations of the reactants and product remain constant (d) reactants stop forming the products
12. An exothermic reaction is one which involves (a) attainment of dynamic equilibrium (b) loss of heat to the surrounding (c) evolution of gas as it proceeds (d) positive change in value of enthalpy 
13.  Which of the following pH values is likely to be that of a slightly alkaline solution? (a) 2 (b) 5 (c) 7 (d) 8

1.  Consider the reaction represented by the equation. 2502g+ 02g⇌2503(g) ∆H= -197kjmo1-1. Which of the following conditions will not increase the yield of sulphur (vi) oxide? (a) increase in temperature (b) decrease in temperature (c) increase in pressure (d) addition of 02 into the mixture
2.   Which of the following lowers the activation energy of a chemical reaction? (a) freezing mixture (b) reducing agent (c) water (d) catalyst 
3. If the value of ∆H for a reaction is negative, it means that the reaction is (a) slow (b) exothermic (c) endothermic (d) irreversible
4.  What does ∆H represent in the following equation? CL(g) + C -> CL ∆H = -363kjmo1-1 (a) Ionization energy (b) electronafinity (c) dissociation energy (d) heat of atomization.
5.  An increase in the rate of a  chemical reaction on heating is due to increase in  (a) activation energy (b) enthalpy (c) collision rate (d) reactant concentration
6.  Which of the following would change the colour of blue litruis paper? An aquesus solution of (a) ammonla (b) chlorine (c) sodium chloride (d) potassium hydroxide 
7.  An acid is said to be weak, if it (a) can be mixed with water in any proportion (b) is not corrosive (c) does not conize completely in aquesus (d) has low pH
8.  A solution of pH7 is (a) Acidic (b) Neutral (c) concentrated (d) dilute
9.  Which of the following methods is/are used for the extraction of the Alkali metals? (a) reduction by the use of carbon (b) roasting of the ore in air (c) thermal reduction (d) reduction by electrolysis
10.  Consider the equation for the equilibrium reaction reaction N2(g)+ 3H2(g) ⇌ 2NH3(g) ∆H= 92kuml-1. The equilibrium constant for the reaction can be expressed as (a)  Kc= 2[NH3]  (b) Kc=  [NH3]2            (c) Kc= 3[H2][N2]     (d) Kc= [N2][H2]3

1.  A solution which dissolves more solutes than it can normally hold at a particular temperature is said to be (a) hydrated (b) saturated (c) super saturated (d) insaturated
2.  Water hardness could be caused by the presence of (a) sodium aluminum trioxo- silicate(iv) (b) calcium hydrogen trioxo carbonate (iv) (c) calcium trioxocarbonate(iv) (d) sodium hydroxide 
3.  The method that can be used to convert hardwater to soft water is (a) chlorination (b) passage over treated (c) the use of an ion-exchange resin (d) aeration
4.  Which of the following processes will pollute water (a) addition of a measured quality of chlorine to water (b) discharge of industrial effluents into water ways (c) exposure of a body of water to ultra violet rays (d) passage of river water through a sand bed
5.  What volume of 0.05moldm3 of Naolt? (a) 5cm (b) 10cm3 (c) 203 (d) 50cm3
6.  For which of the following titrations is phenolphthalein a suitable indicator [i] strong Acid ad weak base [ii] strong acid and weak base [iii] weak acid and story base.  (a) I only (b) I and ii only (c) I and iii only (d) ii and iii only
7.  Calculate the concentration of the solution in moles/ dm3; 14g of potassium hydroxide in 1dm3 (a) 0.25m (b) 4m (c) 0.5m (d) 0.005m

THEORY

Answer question number one and any other 3 question 

Alternative to Practical

1. A is 0.100 moldm-3 of HCL. B is a solution containing 15.0gdm-3 of a mixture of Nach and KHC03 

1. Put A into the burette and titrate it against 25cm3 of your pipette. Tabulate your burette readings and calculate the average volume of A used. The equation for the reaction involved in the titration is HCL+KHCO3KCL(9q)+CO2+H20 [volume of Acid=24.00, 23.80, 23.80]. Tabulate your readings.
2. From your result and information provided above, calculate:

1. Concentration of KHCO3 in moldm-3 in B
2. Mass of KHCO3 in gldm-3 in B [K=39,H=1, C=12, 0=16]  

1. Define each of the following terms; 

1. Activation energy 
2. Entropy 
3. Collision theory 
4. Exothermic process
5. Endothermic process

1. a. State LEChatelier’s principle.

b.List and explain factors affecting equilibrium

1. List and explain 5 factors affecting the rate of chemical reactions 
2. Explain with note and diagram the processes involved in the treatment of water 
3. Explain the following terms; (i) solution (ii) suspensions (iii) collards (iv) saturated solution 
4. The average volume of NaHso4 in a band of toilet clever was 25.10cm3. A solution containing 15.0g of the cleaner perdm3 was titrated against 25.0cm3 portion of 0.1m NaOH, using phenolpthalan as the indicator. Calculate.

1. Concentration of NaHso4 in moleldm3
2. The mass of NaHso4 in 15.0g of the cleaner 

Equation: NaHS04+NaoH=> Na,so4+H20