CLASS TEST
CHAPTERS:
ENDOTHERMIC EXOTHERMIC REACTIONS
DENSITY.
Q1. Differentiate between endothermic and exothermic reactions.
Also give an example each .
4.
Q2. Quicklime is generated in a lime-kiln.
a) Is it an endothermic or exothermic process?
1
_________________________________
b) Write the word equation for the reaction happening in the lime-kiln. 3
__________________________________________________
c) Why is hot air circulated through the kiln?
1
____________________________________________________________
____________________________________________________________
____________________________________________________________
Q3. a)Of the two processes in living things, photosynthesis and respiration,
Which one is endothermic and which one is exothermic?
1
____________________________________________________________
____________________________________________________________
b) Write the chemical equation for respiration.
4
__________________________________________________________
Q4. Of melting and freezing , which is endothermic ,
2
which is exothermic and why?
____________________________________________________________
____________________________________________________________
____________________________________________________________
Q5. Define density. What is the S.I unit of Density?
2
Q6. How will you find the density of a cube with side 5 cm and mass = 30 g.
2
Q7.Explain how will you find the density of a round pebble? 3
Q8. Why do some objects float , while others sink in water ?
2
Q9. Methanol and ethanol are both fuels. A group of students was asked to
carry out an experiment to find out which was the better fuel. The students
used a spirit burner, filled with the fuel, to heat 100 cm3 of water in a
beaker. They measured the temperature of the water and recorded their
results in a table.
Methanol
Ethanol
Mass of spirit burner and fuel before heating
140.5 g
136.8 g
Mass of spirit burner and fuel after heating
140.0 g
136.3 g
Volume of water used
100 cm3
100 cm3
Temperature of water before heating
20°C
21°C
Temperature of water after heating
25°C
29°C
State which is the better fuel and give a reason for your answer.
1
Q 11Of the following which one is an exothermic reactions.
a) Sherbet in the mouth.
b) Baking soda solution and vinegar
c) Baking soda and calcium chloride.
Q12 Harry has a cuboid made of brick and one made of sponge. He wants
to find out which of the cuboids is densest.
a) Harry calculates that the brick has a volume of 246 cm and mass of
4,500g. Calculate its density.
1
____________________________________________________________
____________________________________________________________
b) The length of the sponge is 10cm, its width is 6cm and height is
4cm.Calculate the mass of the sponge ,given that its density is 0.2
g/cm3.
2
____________________________________________________________
____________________________________________________________
c) Which of the cuboids is densest?
1
____________________________________________________________