Experimental Techniques (Worksheet)

 

Secondary 3 : Chemistry

Chapter : Experimental Technique  (Worksheet #1)

 

 

MULTIPLE CHOICE QUESTION

1.   A student mixed 25 cm3 sample of dilute hydrochloric acid with different volumes of aqueous sodium hydroxide. Each time, the student measures the change in temperature to test if the reaction is exothermic.

Which piece of apparatus is not needed ?

2.    In a experiment, a student needs to measure out 35.50 of a solution.

Which piece of apparatus would measure this volume most accurately ?

A.    Burette

B.    Beaker

C.    Measuring cylinder

D.    Pipette

 

3.    The International System of Units uses the symbol mole to represent

A.    Mass

B.    Time

C.    Length

D.    Amount of substance

4.    What is the reading shown by the thermometer ?

A.    44.8

B.    44.5

C.    46.2

D.    45.2

5.    Calcium carbonate reacts with hydrochloric acid, producing carbon dioxide gas.

The total product of gas carbon dioxide can be measured using the apparatus shown

        Which additional piece of apparatus is also required?  

A.    A burette

B.    A gas syringe

C.    A clock

D.    A thermometer

6.   A gas X is soluble in the water and less dense.

Which method can be used to collect the gas ?

7.   The diagram shows copper (II) oxide being reduced, by hydrogen, to copper. After reduction is complete, the burner is turned off but the flow of hydrogen is continued until the tube is cool.

Why is the hydrogen allowed to flow through the tube during cooling ?

A.    To allow the tube to cool slowly

B.    To lessen the risk of explosion in the hot tube

C.    The prevent the copper from reacting with the air

D.    To remove any traces of water left in the tube

 

8.   Magnesium (II) carbonate powder was heated. The loss in mass was plotted against time as shown on the graph.

During which time interval is the reaction fastest ?

A.    0 to 2 min              B. 2 to 4 min            C. 6 to 8 min            D. 8 to 10 min

 

9.   Which of the following gases is the lightest ? (source : All about chemistry Guide for O level)

A.    Ammonia

B.    Oxygen

C.    Hydrogen

D.    Sulfur dioxide

 

10. Gas X is produced when a mixture of ammonium chloride and calcium oxide is heated. The gas is dried by passing it through quicklime and collected by upward delivery. Which of the following statements is not correct about gas X ? (source : All about chemistry Guide for O level)

A.    Gas X turns moist litmus blue

B.    Gas X is less dense than air

C.    Gas X does not dissolve in water

D.    Gas X react with concentrated sulfuric acid

 

ANSWER KEY

1.           A

2.           A

3.           D

4.           A

5.           B

6.           B

7.           C

8.           A

9.           C

10.       C

 

Secondary 3 - Chemistry

Chapter : Experimental Technique (Worksheet #2)

 

 

Structured Question

 

1.  Water is heated from 25 C until it boils.

• What is the boiling point of water on the Kelvin scale ?
•      How much is the rise in temperature of the water on the Kelvin scale
•      Draw the set up to determine the boiling point of water. 

2.    Gas X has the following properties

·       Turns litmus red

·       Less dense than air

         A student carried out the following procedure to collect a dry sample of gas X

         Step I  : Pass the gas through a U- tube containing quicklime

         Step II : Collect the gas by downward displacement of air.

Will he able to obtain a dry sample of gas X? Give your reasons.(source : All about chemistry Guide for O level)

3.   You are required to prepare a solution of sugar in water given the following materials:

·       22.3 g of sugar

·       100 cm3 of distilled water

a.    What apparatus would you use to obtain 22.3 g of sugar?

b.    How do you measure out 100 cm3 of water

c.    What apparatus would you use to prepare the sugar solution?

4.    How can the change in mass of the reaction mixture over a period time be used to determine the speed of the reaction? (source : All about chemistry Guide for O level)

5.   Give the SI unit for measuring the following physical quantities

(a)  Mass of powder of magnesium

(b)  Temperature of water in a beaker

(c)  Volume of hydrogen gas in a syringe

(d)  Time taken for the reaction to go to complete

 

 

ANSWER KEY

1.    A. Boiling of water is 100^O C and then convert to Kelvin scale (273 K)

    T ^oC = (T+273) K , Hence, 100^oC = 100 +273 = 373K

B.  Temperature rise = 100-25 = 75^oC, 1^oC has exactly the same magnitude as 1 K

  Hence, temperature rise on the kelvin scale is also 75K

C.     

2.   No, turning litmus red means gas X is acidic, hence gas X will react with quicklime and will be absorbed. It is a correct procedure to collect a gas less dense than air by upward delivery

3.   a. The weight of sugar using a beam balance

 b.  use a 100 cm³ measuring cylinder

 c.  A 100 cm³ beaker

4.  The fastest changes mass of the reaction mixture over period, the fastest the speed of reaction

5.  (a) kilogram (kg) or gram (g)

(b) Celsius (C)

(c)  centimeter cubic (cm³)

(d) second (s)

 

 

 

 

 

 

Ayutya

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