HHS O Level School
Revision Work sheet 1 – General Science Class VI
Chapter 6: The Particle Model
Answer Key
Q1. State whether each of the following statement is true or false. For each
statement, justify your answer.
a. Gases can be compressed under pressure while liquids cannot. ( True )
Reason: Gases are compressible because the intermolecular space is very large in gases, whereas liquids
are not compressible because, in liquids, the intermolecular space is less.
b. Water is denser than iron.
(False)
Answer: False.
The density of iron is 7.86 g/cc incomparison to water that is 1 g/cc. So it is obvious
that the iron is heavier than the water, hence it will sink into the Water.
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c. Some gases like ammonia diffuse at the faster rate.
( True )
Ammonia (NH3) has the smallest molecular weight so it diffuses the fastest
d. The density of the liquids can be changed by squashing them.
Reason: Applying pressure to a liquid squeezes its molecules closer together, increasing its density.
( True )
Q2. Solve the given numerical. Also show the working.
a. Bismuth phosphate has a density of
b. A cube of length 2.2 cm has a
6.32g/ml. What is the mass of 25.9 cm3 of
mass of 4gms. What will be its
this substance?
density?
Answer: Ans send on whatshapp
Mass=Density×Volume
Given: Density of bismuth phosphate (𝜌ρ) = 6.32 g/ml
Volume (𝑉V) = 25.9 cm³
Now, we can plug these values into the formula:
Mass=6.32 g/ml×25.9 cm³
Mass=6.32g/ml×25.9cm³
First, let's convert the volume from cm³ to ml since 1
cm³ = 1 ml:
Volume=25.9 cm³=25.9 ml
Volume=25.9cm³=25.9ml
Now, we can calculate the mass:
Mass=6.32 g/ml×25.9 ml
Mass=6.32g/ml×25.9ml Mass=163.528 g
Mass=163.528g
So, the mass of 25.9 cm³ of bismuth phosphate is
163.528 grams.
c. What is the volume of the sample that
has a mass of 20 gm and a density of 4
gm/ml?
d. A substance with mass of 5 kg has a
density of 2 gm/cm3. What will be its
volume?
(Hint: compare the units of mass and
density)
Ans send on whatsapp
Ans send on whatsapp
Q3. What will be the effect of lowering down the temperature on particle movement?
When you lower the temperature, the particles in a substance slow down. It's like when it's colder outside,
people tend to move more slowly. So, as the temperature drops, the particles move less and can even stick
together more tightly. This can lead to things like freezing or condensation, where liquids turn into solids or
gases turn into liquids.
Q4. Draw a Venn diagram to compare the process of diffusion with Brownian motion.
Diffusion and Brownian Motion both
- Random motion of particles
- Particles move from higher concentration to lower concentration
- No external force or energy required
Diffusion
- Spontaneous mixing of substances
- Uniform distribution of particles
- Net movement from higher to lower concentration
Brownian Motion
- Random movement of suspended particles
- Caused by collisions with surrounding fluid molecules
- Evidence for kinetic theory of gases