Physical and Chemical Changes

Q.

When steam is passed over red hot iron, magnetic oxide of iron and hydrogen are obtained. "The reaction between steam and red hot iron is a Reversible Reaction ".What is meant by this statement?

Q.

Give two other examples of a similar type of change?

Q.

Why cannot a chemical change be normally reversed?

Q.

List the observations that helps us to determine when a chemical reaction has taken place. [3 MARKS]

Q. Define sublimation. Give few examples of substances that undergo sublimation.

Q.

(B) Classify the following as physical or chemical change.

8) Stitching a shirt

Q. Identify the substances that do not undergo sublimation.

1. Camphor
2. Wood
3. Coal
4. Napthalene
5. Plastic
6. Wax
7. Dry Ice
8. Sugar

Q.

Classify the following as physical or chemical change.

Dissolving sugar in water

Q.

Classify the following as physical or chemical change.

Painting a wall

Q. Question 2
Rusting of an article made up of iron is called

(a) corrosion and it is a physical as well as chemical change
(b) dissolution and it is a physical change
(c) corrosion and it is a chemical change
(d) dissolution and it is a chemical change

Q. Question 10
A change in the physical state can be brought about
(a) Only when energy is given to the system
(b) Only when energy is taken
(c) When energy is either given to, or taken out from the system
(d) Without any energy change

Q. Question 1 (a)
Classify the following as chemical or physical changes:
a. Cutting of trees

Q. All of the following cannot be broken down further by chemical reactions, by cooling, heating, or by electrolysis, except

निम्नलिखित में से किसके अतिरिक्त अन्य सभी को रासायनिक अभिक्रियाओं, शीतलन द्वारा, ऊष्मन द्वारा या विद्युतअपघटन द्वारा पुनः तोड़ा नहीं जा सकता?

1. Iron
   
   आयरन
2. Carbon
   
   कार्बन
3. Sulphuric acid
   
   सल्फ्यूरिक अम्ल
4. Sulphur
   
   सल्फर

Q. This section contains 1 Matrix Match type question, which has 2 Columns (Column I and Column II). Column I has four entries (A), (B), (C) and (D), Column II has four entries (P), (Q), (R) and (S). Match the entries in Column I with the entries in Column II. Each entry in Column I may match with one or more entries in Column II.
इस खण्ड में 1 मैट्रिक्स मिलान प्रकार का प्रश्न है, जिसमें 2 कॉलम (कॉलम I तथा कॉलम II) हैं। कॉलम I में चार प्रविष्टियाँ (A), (B), (C) तथा (D) हैं, कॉलम II में चार प्रविष्टियाँ (P), (Q), (R) तथा (S) हैं। कॉलम I में दी गयी प्रविष्टियों का मिलान कॉलम II में दी गयी प्रविष्टियों के साथ कीजिए। कॉलम I में दी गयी प्रत्येक प्रविष्टि का मिलान कॉलम II में दी गयी एक या अधिक प्रविष्टियों के साथ हो सकता है।

Match the Columns and choose the appropriate answer
कॉलमों का मिलान करें और सही उत्तर चुनें

	Column I कॉलम I		Column II कॉलम II
(A)	Iron आयरन	(P)	Impure substance अशुद्ध पदार्थ
(B)	Silicon सिलिकन	(Q)	Pure substance शुद्ध पदार्थ
(C)	Sugar शर्करा	(R)	Metal धातु
(D)	Wood लकड़ी	(S)	Metalloid उपधातु

1. A-PQR, B-PQRS, C-P, D-Q
2. A-PS, B-PR, C-P, D-S
3. A-QR, B-QS, C-Q, D-P
4. A-P, B-QS, C-R, D-S

Q. Differentiate between physical and chemical change.

Q. Burst the bubbles that contain examples of matter.

1. Almond
2. Sponge
3. Chalk
4. Soft drink
5. Sadness
6. Air
7. Time
8. Water bottle

Q. Which of the following substances will undergo a chemical change if kept in the open for a week?

1. 
2. 
3. 

Q. Which of the following does not represent a change?

1. Stretching of a rubber band
2. Adding kerosene to water
3. Dissolving sugar in water to make a cool drink
4. Formation of curd from milk

Q. Question 1 (c)
Classify the following as chemical or physical changes:
c. Rusting of almirah

Q. Identify the reaction from the following in which physical and chemical changes are occurring:

1. $HCl+NaOH\to NaCl+H_{2}O$
2. $CaC{O}_3\to CaO+C{O}_2$
3. $2N_2{O}_5\to 4N{O}_2+O_2$
4. $CuS{O}_4.5H_{2}O\to CuS{O}_4\left(s\right)+5H_{2}O\left(g\right)$

Q.

2 . In a chemical change, a new substance is formed.

1. True
2. False

Q. Two substances, A and B were made to react to form a third substance, \(A_2B\), according to the following reaction:
2A + B → \(A_2B\)
Which of the following statements concerning this reaction is/are correct?
i) Substance \(A_2B\) shows the properties of substances A and B.
ii) Formation of \(A_2B\) is a chemical change.
iii) \(A_2B\) will always have a fixed composition.
iv) Substances A and B are classified as compounds.

Q.

Rusting of iron is ___________ change.

Q. Which of the following are chemical changes?

1. Burning of coal
2. Rusting of iron
3. Cooking an egg
4. Chopping of wood
5. Freezing of water
6. Digestion of food
7. Tearing of paper
8. Baking a cake

Q. Reaction takes place in aluminothermic process is also known as _______ .

1. thermite reaction
2. thermal reaction
3. decomposition reactions
4. catalytic reaction

Q. Which is not an indicator of chemical reaction? [1 mark]
A. Change in colour
B. Change in state
C. Change in mass
D. Change in temperature

Q.

By giving a reason state why chemical change takes place in the following case: Rusting of iron

Q.

Which among the following are physical or chemical changes?

Burning of Liquefied Petroleum Gas (LPG).

Q. Identify the combination reaction in the following

1. $N{H}_3+HCI\to N{H}_{4}Cl$
2. $NaCl+KOH\to NaOH+KCI$
3. $2CO+O_2\to 2C{O}_2$
4. $Cu(OH{)}_2\stackrel{heat}{\to }CuO+H_{2}O$

Q.

As said that in a chemical reaction original material cannot be recovered then is:

N2+3H2 giving 2NH3+heat

areversible change.