🌟 Class
8 Science – Curiosity Chapter 9
🧪 The Amazing World of
Solutes, Solvents & Solutions
🟢 1.
State whether the statements given below are True [T] or False [F]. Correct the
false statement(s).
✅
Answer:
🟢 2.
Fill in the blanks.
(i) The volume of a solid can be measured by the method of
displacement, where the solid is ______ in water and the ______ in water level
is measured.
(ii) The maximum amount of ______ dissolved in ______ at a
particular temperature is called solubility at that temperature.
(iii) Generally, the density ______ with increase in
temperature.
(iv) The solution in which glucose has completely dissolved
in water, and no more glucose can dissolve at a given temperature, is called a
______ solution of glucose.
✅
Answer:
(i) 👉 immersed,
rise 💧
(ii) 👉 solute,
solvent 🧪
(iii) 👉 decreases
🌡️⬇️
(iv) 👉 saturated
✔️
🟢 3. You
pour oil into a glass containing some water. The oil floats on top. What does
this tell you?
✅
Answer:
👉
Correct option: (ii) Water is denser than oil
🟢 4. A
stone sculpture weighs 225 g and has a volume of 90 cm³. Calculate its density
and predict whether it will float or sink in water.
✅
Answer:
📌
Formula:
👉
Density = 225 / 90 = 2.5 g/cm³
📊
Comparison:
- Water
= 1 g/cm³
- Object
= 2.5 g/cm³
👉 It
will sink (डूबेगा) ⬇️
🟢 5.
Which one of the following is the most appropriate statement and why are the
other statements not appropriate?
✅
Answer:
👉
Correct: (iii) ✔️
🟢 6. You
have a bottle with a volume of 2 litres. You pour 500 mL of water into it. How
much more water can the bottle hold?
✅
Answer:
📌 2 L = 2000
mL
👉
Remaining = 2000 – 500 = 1500 mL
💧 Final:
Bottle can hold 1500 mL (1.5 L) more
🟢 7. An
object has a mass of 400 g and a volume of 40 cm³. What is its density?
✅
Answer:
📌
Formula:
👉
Density = 400 / 40 = 10 g/cm³
🟢 8.
Analyse Fig. 9.25a and 9.25b. Why does the unpeeled orange float, while the
peeled one sinks? Explain.
✅
Answer:
🍊 Unpeeled
Orange:
- Air
pockets present 🌬️
- Density
↓ →
floats ⬆️
🍊 Peeled
Orange:
- No
air spaces
- Density
↑ →
sinks ⬇️
🟢
Question 9 and 10 of Class 8 Science Curiosity Chapter 9
🟢 9.
Object A has a mass of 200 g and a volume of 40 cm³. Object B has a mass of 240
g and a volume of 60 cm³. Which object is denser?
✅
Answer:
📌
Formula:
genui{"math_block_widget_always_prefetch_v2":{"content":"\text{Density}
= \frac{\text{Mass}}{\text{Volume}}"}}
📊
Comparison:
👉 Object
A is denser (अधिक घनत्व वाला) ✔️
🟢 10.
Reema has a piece of modeling clay that weighs 120 g. She first moulds it into
a compact cube that has a volume of 60 cm³. Later, she flattens it into a thin
sheet. Predict what will happen to its density.
✅
Answer:
📌
Formula:
👉
Density = 120 / 60 = 2 g/cm³
🧠
Concept:
👉 Density
remains SAME ✔️
🟢 Class
8 Science Curiosity Chapter 9 Question 11 and 12
🟢 11. A
block of iron has a mass of 600 g and a density of 7.9 g/cm³. What is its
volume?
✅
Answer:
📌
Formula:
👉 Volume
= 600 / 7.9 ≈ 75.95
cm³
🟢 12.
You are provided with an experimental setup as shown in Fig. 9.26a and 9.26b.
On keeping the test tube (Fig 9.26b) in a beaker containing hot water (~70°C),
the water level in the glass tube rises. How does it affect the density?
✅
Answer:
🌡️ When
water is heated:
- Particles
gain energy ⚡
- Move
faster 🏃
- Spread
apart ↔️
🧠
Analysis:
👉
Density decreases (घटती है) ⬇️
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